# Loadster > Loadster is a cloud-based load testing and stress testing platform for websites, web applications, and APIs. It simulates virtual users, called bots, to measure performance and scalability under heavy traffic and to find where a system breaks. A key differentiator is real browser load testing at massive scale: Browser Bots and Playwright Test scripts drive real Chrome browsers, and Loadster customers have run load tests with more than 170,000 concurrent browsers. Lightweight Protocol Bots run HTTP-level tests that scale to millions of concurrent bots. Another differentiator is that the same load testing scripts can also power 24/7 synthetic monitoring, so a script written for a load test can watch the site around the clock and alert on downtime or broken user flows. ## Key Capabilities - **Load Testing**: Run thousands of concurrent virtual users against your site to find performance bottlenecks before real users do. - **Real Browser Scale**: Browser Bots and Playwright Test scripts drive real Chrome browsers on managed cloud infrastructure, with no fixed platform cap; practical scale depends on regions and cloud capacity. How it scales, and what limits it, is documented at https://loadster.com/faqs/maximum-concurrent-bots-or-virtual-users/index.md - **Site & API Monitoring**: Continuously monitor websites, web applications, and APIs around the clock for downtime and broken user flows, using the same scripts that drive load tests. - **Three Scripting Options**: Protocol Bots (HTTP-level), Browser Bots (real Chrome browsers), and Playwright Test scripts (code-first JavaScript). Browser and Playwright scripts are written as user actions, navigating, clicking and typing, rather than as chains of individual HTTP requests that have to be strung together by hand. For modern websites and web applications that is usually both quicker to script and more realistic, because each bot exercises the same client-side code path as a real user. Protocol Bots cost far less per bot and remain the better fit for APIs and simple sites, so many teams mix the two: real browsers for critical flows, protocol for broad throughput. - **32 Cloud Regions**: Run tests from AWS and GCP regions worldwide, or self-host engines on your own infrastructure. - **CI/CD Integration**: Automate load testing in your continuous integration pipeline. ## Getting Started Sign up for a free Loadster account (every account starts with 50 free fuel units). Record or write a test script using Protocol Bots (HTTP-level), Browser Bots (headless Chrome), or Playwright Test (JavaScript). Play the script in the editor with a single bot to verify it works. Then create a load test scenario to configure how many bots run from which cloud regions, launch the test, and observe real-time results on the dashboard. After the test, analyze the report to find performance bottlenecks. You can also set up 24/7 site monitoring with the same scripts. - [Getting Started Guide](https://loadster.com/manual/) - [Pricing](https://loadster.com/pricing/) ## Links - [Loadster Website](https://loadster.com/) - [Pricing](https://loadster.com/pricing/) - [Support](https://loadster.com/support/) - [Contact](mailto:help@loadster.com) ## Pricing > Loadster plans and pricing. Subscribe to a monthly fuel plan for predictable pricing, or simply add pay-as-you-go fuel as you need it. Loadster is powered by Fuel, a unified currency for load testing and monitoring. Bots burn fuel when they run. Every account starts with 50 free units. Monthly Fuel Plans (1K–20K units, $77–$797/month) offer a discount and unused fuel rolls over. Pay-as-you-go fuel ($97–$997 per 1K–20K units) never expires. Monitoring Plans start at $29/month. Protocol Bots burn 1x fuel; Browser Bots and Playwright scripts burn 4x. Custom, annual, and bring-your-own-cloud plans are also available. - URL: https://loadster.com/pricing/ ## Documentation > The Loadster manual and documentation. Loadster is a cloud-hybrid load testing platform for building scalable websites, web applications, and APIs. - URL: https://loadster.com/manual/ - Markdown: https://loadster.com/manual/index.md - Manifest: https://loadster.com/manual/index.json ### Connecting AI Agents to Loadster - URL: https://loadster.com/manual/ai-agents/ - Markdown: https://loadster.com/manual/ai-agents/index.md - Description: Connect AI agents like Claude, ChatGPT, Cursor, and Codex to Loadster so they can write and play scripts, build load tests, and analyze results. - Keywords: AI Agents, AI Load Testing, Claude, ChatGPT, Cursor, Codex, MCP, Model Context Protocol, Load Testing ### Loadster Cloud Regions in AWS and GCP - URL: https://loadster.com/manual/cloud-regions/ - Markdown: https://loadster.com/manual/cloud-regions/index.md - Description: Loadster can launch clusters on demand for your load tests, from a wide range of geographic regions and across multiple cloud providers. - Keywords: Release Notes ### Protocol Scripts in Loadster - URL: https://loadster.com/manual/protocol-scripts/ - Markdown: https://loadster.com/manual/protocol-scripts/index.md - Description: Loadster's protocol scripts run automated HTTP/HTTPS requests for testing websites and APIs. Chain together requests, add validation, and capture variables. - Keywords: Load Test Scripts, Protocol Scripts ### Site & API Monitoring - URL: https://loadster.com/manual/monitoring/ - Markdown: https://loadster.com/manual/monitoring/index.md - Description: Monitor your site 24/7/365 with Loadster scripts. Bots run on a schedule and alert you if your site goes down or breaks, so you can take action. - Keywords: Site Monitoring, API Monitoring, Uptime, Downtime, Alerting, Notifications ### Browser Bot Scripting - URL: https://loadster.com/manual/browser-scripts/ - Markdown: https://loadster.com/manual/browser-scripts/index.md - Description: Loadster's browser scripts control real headless Chrome browsers. They're the most realistic way to test complex web applications. - Keywords: Browser Scripts, Browser Bots, Headless Browser Scripting ### Incidents & Notifications - URL: https://loadster.com/manual/incidents-and-notifications/ - Markdown: https://loadster.com/manual/incidents-and-notifications/index.md - Description: Loadster monitors open and close incidents whenever problems are detected, and notify you according to your notification policies. - Keywords: Site Monitoring, API Monitoring, Uptime, Downtime, Alerting, Notifications, Notification Policies, Incident, Escalation, Maintenance Windows ### Integrating Loadster with Opsgenie - URL: https://loadster.com/manual/integration-with-opsgenie/ - Markdown: https://loadster.com/manual/integration-with-opsgenie/index.md - Description: Are you using Opsgenie for incident alerting? Here's how to integrate Loadster with Opsgenie for speedy incident response and escalation. - Keywords: Loadster, Opsgenie, Integration, API Monitoring ### Load Testing On-Premises with Loadster Engine - URL: https://loadster.com/manual/testing-with-loadster-engine/ - Markdown: https://loadster.com/manual/testing-with-loadster-engine/index.md - Description: If you need to load test on-premises or in a private cloud environment, you can run your own Loadster Engines and control them from Loadster. - Keywords: Distributed Load Test, Load Testing Private Network, Windows Performance Tuning, Linux Performance Tuning, Windows Ephemeral Ports, Ephemeral Port Range, File Descriptors ### Hosted Status Pages - URL: https://loadster.com/manual/status-pages/ - Markdown: https://loadster.com/manual/status-pages/index.md - Description: When Loadster is monitoring your site, a status page displays current monitoring data and uptime to your team or the general public. - Keywords: Status Page, Site Monitoring, API Monitoring, Uptime, Downtime, Incidents ### Integrating Loadster with PagerDuty - URL: https://loadster.com/manual/integration-with-pagerduty/ - Markdown: https://loadster.com/manual/integration-with-pagerduty/index.md - Description: Integrate Loadster with PagerDuty to create incidents when a monitor fails, and automatically resolve them when it recovers. - Keywords: Loadster, PagerDuty, Integration, API Monitoring ### Playwright Scripting - URL: https://loadster.com/manual/playwright-scripts/ - Markdown: https://loadster.com/manual/playwright-scripts/index.md - Description: Loadster supports the Playwright Test framework for load testing and monitoring, ideal for developers who prefer writing tests in JavaScript or TypeScript. - Keywords: Playwright Scripts, Playwright Test, Code-Based Scripting, JavaScript Testing ### Terms & Definitions - URL: https://loadster.com/manual/terms-and-definitions/ - Markdown: https://loadster.com/manual/terms-and-definitions/index.md - Description: Key terms and definitions related to load testing web applications, web services, and static websites with Loadster. - Keywords: Load Testing Web Applications, Web Applications, Load Testing, Loadster Manual, Loadster Documentation ### Using the Loadster CLI - URL: https://loadster.com/manual/loadster-cli/ - Markdown: https://loadster.com/manual/loadster-cli/index.md - Description: The Loadster CLI lets you launch load tests and check results from the command line, enabling CI/CD integration with Jenkins, GitHub Actions, and more. - Keywords: Load Testing, Continuous Integration, Continuous Delivery, CI, Loadster CLI ### Code Blocks for Advanced Scripting - URL: https://loadster.com/manual/code-blocks/ - Markdown: https://loadster.com/manual/code-blocks/index.md - Description: JavaScript code blocks in Loadster. Use code blocks in Protocol Scripts and Browser Scripts for function reuse, looping, and conditional logic. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block ### Integrating Loadster with Slack - URL: https://loadster.com/manual/integration-with-slack/ - Markdown: https://loadster.com/manual/integration-with-slack/index.md - Description: Here's how to integrate Loadster with Slack, so you can find out quickly when monitors fail and recover or your team runs tests. - Keywords: Loadster, Slack, Integration, API Monitoring ### Load Testing with Continuous Integration - URL: https://loadster.com/manual/load-testing-with-continuous-integration/ - Markdown: https://loadster.com/manual/load-testing-with-continuous-integration/index.md - Description: How to integrate Loadster load testing into your CI/CD pipeline, so you can automatically track performance changes with every build or release. - Keywords: Load Testing, Continuous Integration, Continuous Delivery, CI, Loadster CLI ### Integrating Loadster with VictorOps (Splunk On-Call) - URL: https://loadster.com/manual/integration-with-victorops/ - Markdown: https://loadster.com/manual/integration-with-victorops/index.md - Description: How to integrate Loadster with VictorOps (now Splunk On-Call) for fast incident routing and resolution. - Keywords: Loadster, VictorOps, Splunk On-Call, Integration, API Monitoring ### Script Variables & Expressions - URL: https://loadster.com/manual/variables-and-expressions/ - Markdown: https://loadster.com/manual/variables-and-expressions/index.md - Description: Use variables and expressions in Loadster to add dynamic data to your test scripts. Prepopulate variables from a dataset or set them at runtime. - Keywords: Script Variables ### Dynamic Datasets and Script Variables - URL: https://loadster.com/manual/dynamic-datasets/ - Markdown: https://loadster.com/manual/dynamic-datasets/index.md - Description: Loadster's dynamic datasets are a way to prepopulate your script variables with canned data, such as user accounts or search phrases. Here's how. - Keywords: Datasets, Variables ### Integrating Loadster with Webhooks - URL: https://loadster.com/manual/integration-with-webhooks/ - Markdown: https://loadster.com/manual/integration-with-webhooks/index.md - Description: How to integrate Loadster with your own systems or a system of your choosing with flexible webhooks. - Keywords: Loadster, Webhook, Integration, API Monitoring ### Load Test Scenarios and Configuration - URL: https://loadster.com/manual/load-test-scenarios/ - Markdown: https://loadster.com/manual/load-test-scenarios/index.md - Description: How to configure a Loadster load test scenario: choose how many bots run your scripts, from which cloud regions, and with what ramp-up schedule. - Keywords: Concurrent Users, Virtual Users, Loadster Scenario ### Running Load Tests - URL: https://loadster.com/manual/running-load-tests/ - Markdown: https://loadster.com/manual/running-load-tests/index.md - Description: Here's how to launch and run load tests with Loadster, observing results with the real-time dashboard and charts. What do all the graphs mean? - Keywords: Response Time, Network Throughput, Transaction Throughput, Errors, Virtual Users, Load Engines, CPU Utilization, Memory Utilization, Latency ### Analyzing & Interpreting Load Test Results - URL: https://loadster.com/manual/analyzing-test-results/ - Markdown: https://loadster.com/manual/analyzing-test-results/index.md - Description: How to read and interpret Loadster load test reports, including response times, throughput, error rates, and resource utilization metrics. - Keywords: Load Test Report, Response Time, Network Throughput, Transaction Throughput, Errors, Virtual Users, Load Engines, CPU Utilization, Memory Utilization, Latency ### Loadster Single Sign-On Guide - URL: https://loadster.com/manual/sso/ - Markdown: https://loadster.com/manual/sso/index.md - Description: Loadster offers SSO with SAMLv2 with certain annual and custom plans. Setting up Single Sign-On is generally fairly straightforward. - Keywords: SAML, SSO, Okta, Google Workspace, Microsoft Entra ## Protocol Scripts in Loadster > Loadster's protocol scripts run automated HTTP/HTTPS requests for testing websites and APIs. Chain together requests, add validation, and capture variables. ### Validation Rules in Protocol Scripts - URL: https://loadster.com/manual/protocol-scripts/validation-rules/ - Markdown: https://loadster.com/manual/protocol-scripts/validation-rules/index.md - Description: Using validation rules in Loadster. Validating response time, response size, and content. Advanced JavaScript validators. - Keywords: Validation, Content Validation, Response Time Validation, Response Size Validation, JavaScript Validation, Assertions ### Capturing Rules for Protocol Scripts - URL: https://loadster.com/manual/protocol-scripts/capturing-rules/ - Markdown: https://loadster.com/manual/protocol-scripts/capturing-rules/index.md - Description: Using capturing rules in a Loadster protocol script, to capture or extract values from an HTTP response, and use them later in your script. - Keywords: Extractor, Capturer, Regular Expression, JavaScript ### OpenAPI/Swagger Import - URL: https://loadster.com/manual/protocol-scripts/openapi-swagger/ - Markdown: https://loadster.com/manual/protocol-scripts/openapi-swagger/index.md - Description: Loadster integrates with OpenAPI and Swagger, so you can easily create steps in your script from an API specification. - Keywords: REST API, OpenAPI, Swagger ## Browser Bot Scripting > Loadster's browser scripts control real headless Chrome browsers. They're the most realistic way to test complex web applications. ### Evaluate Blocks for Browser Scripts - URL: https://loadster.com/manual/browser-scripts/evaluate-blocks/ - Markdown: https://loadster.com/manual/browser-scripts/evaluate-blocks/index.md - Description: When normal browser automation isn't cutting it, use Evaluate Blocks to run or evaluate custom JavaScript inside the browser with Loadster. - Keywords: Script Editing, JavaScript, Eval, Evaluate ## Playwright Scripting > Loadster supports the Playwright Test framework for load testing and monitoring, ideal for developers who prefer writing tests in JavaScript or TypeScript. ### Playwright Bot Reference - URL: https://loadster.com/manual/playwright-scripts/bot/ - Markdown: https://loadster.com/manual/playwright-scripts/bot/index.md - Description: The @loadster/bot module for Playwright scripts — access dataset variables, bot metadata, and timing functions in your Playwright tests. - Keywords: Playwright Scripts, Playwright Test, Dataset Variables, Bot Module, @loadster/bot ### Organizing Playwright Scripts (POM) - URL: https://loadster.com/manual/playwright-scripts/organizing-scripts/ - Markdown: https://loadster.com/manual/playwright-scripts/organizing-scripts/index.md - Description: How to organize Playwright scripts in Loadster—start simple, then add helper functions, page objects (POM), and fixtures as your scripts grow. - Keywords: Playwright Scripts, Page Object Model, POM, Test Organization, Reusable Scripts, @loadster/bot ## Code Blocks for Advanced Scripting > JavaScript code blocks in Loadster. Use code blocks in Protocol Scripts and Browser Scripts for function reuse, looping, and conditional logic. ### Bot Object Reference - URL: https://loadster.com/manual/code-blocks/bot/ - Markdown: https://loadster.com/manual/code-blocks/bot/index.md - Description: The bot object in Loadster code blocks - methods for timing control, variable management, iteration handling, bot identification, and test flow control. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block, Bot Object ### HTTP Object Reference - URL: https://loadster.com/manual/code-blocks/http/ - Markdown: https://loadster.com/manual/code-blocks/http/index.md - Description: The http object in Loadster code blocks - methods for making HTTP requests, managing headers, and handling authentication programmatically. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block, HTTP Object, HTTP Requests ### Browser Object Reference - URL: https://loadster.com/manual/code-blocks/browser/ - Markdown: https://loadster.com/manual/code-blocks/browser/index.md - Description: The browser object in Loadster code blocks - methods for page interaction, window management, authentication, and browser configuration control. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block, Browser Object, Browser Scripts ### Formats Object Reference - URL: https://loadster.com/manual/code-blocks/formats/ - Markdown: https://loadster.com/manual/code-blocks/formats/index.md - Description: The formats object in Loadster code blocks - methods for encoding, decoding, timestamp generation, UUIDs, and random data creation for testing. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block, Formats Object, Encoding, Decoding ### XML Object Reference - URL: https://loadster.com/manual/code-blocks/xml/ - Markdown: https://loadster.com/manual/code-blocks/xml/index.md - Description: The XML object in Loadster code blocks - methods for parsing XML data, navigating elements, and extracting values using the xmldoc library. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block, XML Object, XML Parsing ### JSON Object Reference - URL: https://loadster.com/manual/code-blocks/json/ - Markdown: https://loadster.com/manual/code-blocks/json/index.md - Description: The JSON object in Loadster code blocks - methods for parsing JSON data, creating payloads, and validation using standard JavaScript JSON methods. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block, JSON Object, JSON Parsing ### Crypto Object Reference - URL: https://loadster.com/manual/code-blocks/crypto/ - Markdown: https://loadster.com/manual/code-blocks/crypto/index.md - Description: The crypto object in Loadster code blocks - methods for hashing, HMAC generation, authentication signatures, and cryptographic functions. - Keywords: Automated Testing, Script Editing, JavaScript, Code Block, Crypto Object, Hashing, HMAC ## Guides > Performance engineering is a broad topic that extends beyond load testing. These guides cover performance, scalability, stability, and optimization. ### Software Performance Engineering: A Practical Guide - URL: https://loadster.com/guides/performance-engineering/ - Markdown: https://loadster.com/guides/performance-engineering/index.md - Description: Software performance engineering builds speed and scalability into systems from design through production. Learn the practice, tools, and where testing fits. - Summary: Performance engineering is the practice of building speed, scalability, and stability into software throughout its lifecycle. This guide covers the performance engineering process, the responsibilities involved, the tools teams commonly use, and the role of performance testing. - Keywords: Performance Engineering, Software Performance Engineering, What is Performance Engineering, Performance Engineering vs Performance Testing, Performance Engineering Tools, Performance Engineering Services, Performance Engineer ### Load Testing Guide: Types, Tools, and Best Practices - URL: https://loadster.com/guides/load-testing/ - Markdown: https://loadster.com/guides/load-testing/index.md - Description: Load testing simulates heavy traffic to measure your site's performance and scalability. Learn the types of load tests, what tools are used, and how to run one. - Summary: Load testing (including stress testing, spike testing, and stability testing) is the technique of simulating real users interacting with your site, to see how it performs under heavy load. Proper load testing helps to reduce the risk of site failure in the event of a traffic surge. - Keywords: Load Testing, Load Testing Tool, Load Testing Tools, Load Testing Software, Load Testing Platform, Load Testing Guide, What is Load Testing, How to Load Test, Stress Testing ### How to Load Test a Website: A Step-by-Step Guide - URL: https://loadster.com/guides/website-load-testing/ - Markdown: https://loadster.com/guides/website-load-testing/index.md - Description: How to load test a website, step by step: plan your traffic, build realistic test scripts, run the load test, and read the results with confidence. - Summary: We've all seen websites crash under a flood of traffic. When it happens to your site, it's costly and stressful! Preparing your site so it doesn't crash under heavy traffic is often a worthwhile investment, but how can you predict the breaking point at which your site will crash or become slow under heavy load? - Keywords: How to Load Test a Website, How to Do Load Testing, How to Perform Load Testing, Website Load Testing, Load Test Website, Load Testing Website, Website Performance Testing, Prevent Site Crashes ### Performance Testing Guide: Types, Metrics, and Process - URL: https://loadster.com/guides/performance-testing/ - Markdown: https://loadster.com/guides/performance-testing/index.md - Description: Performance testing measures how a system responds under realistic and heavy usage. Learn the types of performance tests, key metrics, and how to run them. - Summary: Performance testing measures how a website, application, or API behaves under realistic and heavy usage. This guide covers load, stress, soak, and spike testing, the metrics each test produces, and a practical process for planning, running, and analyzing performance tests. - Keywords: Performance Testing, What is Performance Testing, Software Performance Testing, Types of Performance Testing, Performance Testing Metrics, Performance Testing Tools, Performance Testing Process ### API Load Testing and Performance Testing Guide - URL: https://loadster.com/guides/api-performance-testing/ - Markdown: https://loadster.com/guides/api-performance-testing/index.md - Description: How to load test an API: tools, methods, metrics, and pitfalls. A practical guide to API performance testing for REST, GraphQL, and gRPC. - Summary: Your customers want to build on an API that's fast and reliable. Performance problems present a serious risk to your API's stability, but a little performance testing in the right places can greatly reduce your risk of API failure. Because they're meant to be consumed programmatically, APIs are usually great candidates for automated, including load and performance testing. - Keywords: API Performance Testing, API Load Testing, Load Test API, API Stress Testing, REST API Performance Testing, REST API Load Testing, API Load Testing Tool, Performance Testing Web Services ### Load Testing vs Stress Testing vs DDoS: The Differences - URL: https://loadster.com/guides/load-testing-stress-testing-and-ddos/ - Markdown: https://loadster.com/guides/load-testing-stress-testing-and-ddos/index.md - Description: Load testing, stress testing, and DDoS attacks all generate heavy traffic. Here's what each means and how to tell them apart. - Summary: Load testing, stress testing, and DDoS attacks all generate heavy traffic against a web server, so the terms get conflated. This guide explains what each one actually means, who does them and why, and how to tell whether a particular test is legitimate QA or something else. - Keywords: Load Testing vs DDoS, Stress Testing vs DDoS, Difference between Load Testing and DDoS, Is Stress Testing Legal, Load Testing, Stress Testing ### Synthetic Monitoring: Tools and Techniques - URL: https://loadster.com/guides/synthetic-monitoring/ - Markdown: https://loadster.com/guides/synthetic-monitoring/index.md - Description: Synthetic monitoring tests your site or API from outside on a schedule, catching downtime and slowdowns before users do. Learn how it works and the tools. - Summary: Synthetic monitoring runs scripted checks against your site or API on a schedule from outside your infrastructure. This guide explains how synthetic monitoring works, how it differs from real user monitoring and load testing, and what to consider when choosing and configuring a monitoring tool. - Keywords: Synthetic Monitoring, What is Synthetic Monitoring, Synthetic Monitoring Tools, Synthetic Testing, Synthetic Load Testing, Synthetic Monitoring vs RUM, Site Monitoring, API Monitoring ### Load Testing vs Stress Testing: Key Differences Explained - URL: https://loadster.com/guides/load-testing-vs-stress-testing/ - Markdown: https://loadster.com/guides/load-testing-vs-stress-testing/index.md - Description: Load testing and stress testing are often confused. Here's the real difference, when to use each, and how they fit in a performance engineering program. - Summary: Load testing and stress testing both simulate heavy traffic on a website, API, or application, but the motivations, methods, and expected outcomes are different. This guide explains the difference, when each is appropriate, and how most teams end up doing both. - Keywords: Load Testing vs Stress Testing, Stress Testing vs Load Testing, Difference between Load Testing and Stress Testing, Load Testing or Stress Testing, Load Testing, Stress Testing ### Quick and Dirty Performance Tuning: A Pragmatic Approach - URL: https://loadster.com/guides/quick-and-dirty-performance-tuning/ - Markdown: https://loadster.com/guides/quick-and-dirty-performance-tuning/index.md - Description: A guide to quick performance tuning. Use a reproducible load test to measure the impact of each optimization change. - Summary: Performance tuning web applications isn't easy, but it helps to have a methodical and scientific approach. Tuning gets a lot easier when you have a way to generate consistently reproducible traffic and measure the impact of each and every change. Easier said than done? Here's a quick and dirty approach that gets you most of the way there. - Keywords: Performance Tuning, Load Testing ### Web Application Stress Testing: Practical Tips and Examples - URL: https://loadster.com/guides/web-application-stress-testing/ - Markdown: https://loadster.com/guides/web-application-stress-testing/index.md - Description: Stress testing a web application means pushing it past capacity. Stateful flows, databases, and client-side rendering create failure modes that need attention. - Summary: Web applications have more moving parts than static sites — authentication, stateful flows, databases, real-time updates, and client-side rendering all interact under load. Stress testing a web application means pushing it past capacity while watching these components for degradation, failure, and recovery. - Keywords: Web Application Stress Testing, Web App Stress Testing, Stress Testing Web Applications, How to Stress Test a Web Application, Web Application Performance Testing, Stress Test Web App ### Load Testing Costs and Benefits: When Is It Worth It? - URL: https://loadster.com/guides/weighing-the-costs-of-load-testing/ - Markdown: https://loadster.com/guides/weighing-the-costs-of-load-testing/index.md - Description: A guide to the costs and benefits of load testing. When is it worth the investment, and when might you reasonably skip it? - Summary: We make a load testing tool, so it would be tempting to say that you should load test your site early and often, extensively, all the time, no matter what! But the real answer is: it depends. Sometimes it isn't worth it. There are hard and soft costs to load testing that you should weigh against the likelihood and severity of the risk you're trying to mitigate. - Keywords: Load Testing, Costs & Benefits ### Capacity Planning for Servers, Cloud, and Web Apps - URL: https://loadster.com/guides/capacity-planning-for-web-apps/ - Markdown: https://loadster.com/guides/capacity-planning-for-web-apps/index.md - Description: A practical guide to capacity planning for servers, cloud infrastructure, and web applications, so you can handle expected demand and traffic spikes. - Summary: Capacity planning means making sure your servers, cloud infrastructure, and web applications have the capacity to service the expected demand, allowing for fluctuations and traffic spikes. But how can you get the most bang for your buck when capacity planning, without it turning into a dull and cumbersome process? Here is a short, opinionated crash course. - Keywords: Capacity Planning, Server Capacity Planning, Cloud Capacity Planning, IT Capacity Planning, Infrastructure Capacity Planning, Web Application Capacity Planning, Load Testing ### How Many Concurrent Users Can Your Website Handle? - URL: https://loadster.com/guides/how-many-concurrent-users/ - Markdown: https://loadster.com/guides/how-many-concurrent-users/index.md - Description: How many concurrent users your website can handle depends on your stack, not just server specs. Rough estimates, plus how to measure your real limit. - Summary: Every website has a concurrency limit, but server specifications alone can't tell you what it is. This guide gives rough ranges for common hosting setups, explains where bottlenecks typically appear, and shows how to measure your actual limit with a stress test. - Keywords: How Many Concurrent Users Can My Website Handle, Website Concurrent User Capacity, Server Concurrent Users, Website Capacity, Concurrent User Limit, Website Breaking Point ### IT Capacity Management for Cloud and Web Applications - URL: https://loadster.com/guides/capacity-management/ - Markdown: https://loadster.com/guides/capacity-management/index.md - Description: Capacity management is the ongoing practice of matching IT capacity to demand. Learn the process, how it differs from planning, and where testing fits. - Summary: Capacity management is the ongoing practice of making sure your systems have enough capacity to meet demand at a cost within your budget. This guide covers the capacity management cycle, how it differs from capacity planning, and the role of load testing and monitoring. - Keywords: Capacity Management, IT Capacity Management, Cloud Capacity Management, What is Capacity Management, Capacity Management Process, Capacity Management Best Practices, Infrastructure Capacity Management, Capacity and Performance Management, ITIL Capacity Management ### Concurrent Users: Definition and Formulas - URL: https://loadster.com/guides/concurrent-users/ - Markdown: https://loadster.com/guides/concurrent-users/index.md - Description: Concurrent users are the visitors on your site at the same moment. Learn how they differ from visits and RPS, and how to calculate them from analytics. - Summary: Concurrent users are the number of visitors actively using your site at the same time. This guide explains how concurrency differs from visits, sessions, and requests per second, and how to estimate concurrent users from your analytics data for capacity planning and load testing. - Keywords: Concurrent Users, Concurrent Users Meaning, What Are Concurrent Users, Concurrent Users in Performance Testing, Concurrent Users vs Requests Per Second, Calculate Concurrent Users, Little's Law, Little's Law Calculator, Virtual Users ### Soak Testing: Finding Memory Leaks and Slow Burns - URL: https://loadster.com/guides/endurance-testing/ - Markdown: https://loadster.com/guides/endurance-testing/index.md - Description: Soak testing (also called endurance testing) runs sustained load for hours or days to surface memory leaks and other issues that take time to appear. - Summary: Soak testing (also called endurance testing or stability testing) applies steady, moderate load to an application over a long stretch of time (hours or days) to surface problems that don't appear in short tests. This guide covers what soak testing is, what it typically finds, how to run one, and how it fits alongside load and stress testing. - Keywords: Endurance Testing, Endurance Test, Soak Testing, Soak Test, Stability Testing, Software Endurance Testing, Endurance Testing in Software Testing, Testing for Memory Leaks, Memory Leak Testing ### Front-End vs. Back-End Performance: Where to Focus First - URL: https://loadster.com/guides/front-end-vs-back-end-performance/ - Markdown: https://loadster.com/guides/front-end-vs-back-end-performance/index.md - Description: Under peak traffic, the usual 80/20 front-end/back-end ratio can flip. Here's how to tell the difference and where to focus your optimization. - Summary: Is the adage true, that 80% of the time that end users spend waiting on a web page is due to front-end factors? Maybe under normal conditions. But under peak traffic, that ratio can flip. Here's a bit of perspective on where to focus your efforts to ensure your site stays fast and delivers a consistent experience to all your users, all the time. - Keywords: Front End vs Back End Performance, Front End vs Back End, Front End Back End Performance Difference, Front End Performance, Back End Performance, Back End Optimization, Website Performance Front End Back End, Performance Optimization, Avoiding Site Outages ### Concurrency Testing: Deadlocks & Race Conditions - URL: https://loadster.com/guides/concurrency-testing/ - Markdown: https://loadster.com/guides/concurrency-testing/index.md - Description: Concurrency testing checks that a system stays correct when many users act at the same instant, catching race conditions, deadlocks, and data corruption. - Summary: Concurrency testing verifies that a system behaves correctly when many users perform actions at the same time. This guide covers common concurrency bugs, how to create simultaneous traffic with load testing bots, and how to verify the resulting application data. - Keywords: Concurrency Testing, What is Concurrency Testing, Race Conditions, Deadlocks, Simultaneous Users, Data Integrity Under Load, Concurrency Bugs ### Capacity Testing: Finding Your True Maximum Load - URL: https://loadster.com/guides/capacity-testing/ - Markdown: https://loadster.com/guides/capacity-testing/index.md - Description: Capacity testing finds the maximum load a system can handle while still meeting performance targets, so you know your headroom before traffic peaks. - Summary: Capacity testing measures the maximum load a system can handle while still meeting its response time and error-rate targets. This guide explains how capacity testing differs from stress testing, how to run a capacity test, and how to use the results for infrastructure and traffic planning. - Keywords: Capacity Testing, What is Capacity Testing, Capacity Testing in Software Testing, Maximum Concurrent Users, Capacity Headroom, Performance Acceptance Criteria, Website Capacity ### Scalability Testing: Scale Up, Find Bottlenecks - URL: https://loadster.com/guides/scalability-testing/ - Markdown: https://loadster.com/guides/scalability-testing/index.md - Description: Scalability testing measures how performance changes as load and resources grow, so you can verify that adding servers actually adds capacity. - Summary: Scalability testing measures how a system's performance changes as load and infrastructure grow. This guide covers scaling up versus scaling out, how to compare configurations with stepped load tests, and how to use the results for capacity and infrastructure planning. - Keywords: Scalability Testing, What is Scalability Testing, Scalability Testing in Software Testing, How to Measure Scalability, Horizontal Scaling, Vertical Scaling, Scalability Bottlenecks ### Spike Testing: Preparing for Sudden Traffic Surges - URL: https://loadster.com/guides/spike-testing/ - Markdown: https://loadster.com/guides/spike-testing/index.md - Description: Spike testing simulates a sudden burst of traffic to see whether your site absorbs the surge and recovers gracefully. Here's how to plan and run one. - Summary: Spike testing simulates a short, intense burst of traffic to measure how your web application performs during the surge and whether it safely recovers afterwards. This guide explains how spike testing differs from a standard load test, how to build a realistic spike scenario, and how to interpret results. - Keywords: Spike Testing, What is Spike Testing, Website Spike Testing, Web Application Spike Testing, Load Testing vs. Spike Testing, Testing for Traffic Spikes, Traffic Surge Testing ### Load Testing Best Practices: Tips, Pitfalls, and Checklist - URL: https://loadster.com/guides/load-testing-best-practices/ - Markdown: https://loadster.com/guides/load-testing-best-practices/index.md - Description: A guide to load testing best practices, common pitfalls, and a checklist for accurate results. Covers user simulation, requirements, and test reporting. - Summary: Load testing isn't always easy, but doing it right can greatly reduce your risk of site crashes. We've worked with thousands of testers and performance engineers, and assembled a list of load testing best practices and pitfalls to help you be successful in less time. - Keywords: Load Testing Best Practices, Load Testing Tips, Load Testing Checklist, How to Load Test a Website, Load Testing Pitfalls, Load Testing, Performance Testing Best Practices ## Tool Comparisons > Side-by-side load testing tool comparisons and alternatives — Loadster, JMeter, k6, Gatling, Locust, LoadRunner, BlazeMeter — with fact-based advice. ### Best Load Testing Tools and Platforms (2026) - URL: https://loadster.com/compare/load-testing-tools/ - Markdown: https://loadster.com/compare/load-testing-tools/index.md - Description: Compare the best load testing tools for 2026 — Loadster, JMeter, k6, Gatling, BlazeMeter, LoadRunner. Open source vs cloud. Pricing, features, fit. - Summary: When comparing load testing tools, take into account what you are testing, how your team operates, and how much infrastructure you're comfortable owning. This decision guide ranks the leading cloud load testing platforms and open source tools for 2026, then shows when each one is the right fit for typical load testing requirements. - Keywords: Load Testing Tools, Load Testing Tool, Best Load Testing Tools, Top Load Testing Tools, Load Testing Software, Load Testing Platform, Load Testing Tools Comparison, Load Testing Decision Guide, Open Source Load Testing Tools, Cloud Load Testing Tools, Website Load Testing Tools ### Best JMeter Alternatives for Load Testing (2026) - URL: https://loadster.com/compare/jmeter-alternatives/ - Markdown: https://loadster.com/compare/jmeter-alternatives/index.md - Description: The best JMeter alternatives for load testing in 2026 — Loadster, k6, Gatling, Locust, and hosted JMeter — with fact-based reasons to switch or stay. - Summary: JMeter is still a capable load testing tool, but its desktop GUI, XML test plans, and do-it-yourself infrastructure send plenty of teams looking for a JMeter alternative. This guide ranks the leading options, from cloud platforms that import your JMX test plans to modern code-first open source tools, with fact-based reasons to switch or to stay put. - Keywords: JMeter Alternatives, JMeter Alternative, Apache JMeter, Load Testing Tools, Import JMX, JMeter Replacement ### Best k6 Alternatives for Load Testing (2026) - URL: https://loadster.com/compare/k6-alternatives/ - Markdown: https://loadster.com/compare/k6-alternatives/index.md - Description: The best k6 alternatives in 2026 — Loadster, Grafana Cloud k6, Gatling, Locust, and Artillery — with fact-based reasons to switch tools or stay put. - Summary: k6 is an excellent code-first load testing tool, but self-managed infrastructure, a 1,000 browser VU cloud cap, and JavaScript-only scripting send some teams looking for a k6 alternative. This guide ranks the leading options, from cloud platforms that import your k6 scripts to other open source tools, with fact-based reasons to switch or stay. - Keywords: k6 Alternatives, k6 Alternative, Grafana k6, Load Testing Tools, Import k6 Scripts, k6 Replacement ### Best LoadRunner Alternatives for Load Testing (2026) - URL: https://loadster.com/compare/loadrunner-alternatives/ - Markdown: https://loadster.com/compare/loadrunner-alternatives/index.md - Description: The best LoadRunner alternatives in 2026 — Loadster, Tricentis NeoLoad, and BlazeMeter — with fact-based advice on migrating off enterprise licensing. - Summary: LoadRunner (now OpenText Performance Engineering) still owns enterprise performance testing, but its licensing costs and VuGen skill requirements send many teams looking for a LoadRunner alternative. This guide ranks the leading commercial platforms — the realistic landing spots for LoadRunner migrations — with fact-based reasons to migrate or stay. - Keywords: LoadRunner Alternatives, LoadRunner Alternative, OpenText Performance Engineering, Load Testing Tools, VuGen, LoadRunner Replacement ### Gatling vs k6: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/gatling-vs-k6/ - Markdown: https://loadster.com/compare/gatling-vs-k6/index.md - Description: Gatling vs k6 compared: scripting languages, reports, efficiency, and paid cloud options, with fact-based advice on which load testing tool fits your team. - Summary: Gatling and k6 are the two leading code-first open source load testing tools for developer-led teams. Gatling is JVM-based with polished HTML reports and SDKs in five languages; k6 is a Go-powered CLI tool scripted in JavaScript. This guide compares them fact by fact, and covers a third option if neither tradeoff feels right. - Keywords: Gatling vs k6, k6 vs Gatling, Open Source Load Testing Tools, Load Testing Tools Comparison, Gatling Enterprise, Grafana k6 ### JMeter vs LoadRunner: Load Testing Compared (2026) - URL: https://loadster.com/compare/jmeter-vs-loadrunner/ - Markdown: https://loadster.com/compare/jmeter-vs-loadrunner/index.md - Description: JMeter vs LoadRunner compared: cost, scripting, protocol coverage, and enterprise fit, with fact-based advice for choosing between free and enterprise. - Summary: JMeter and LoadRunner are the two longest-standing names in load testing: one free and open source, the other an enterprise suite now sold as OpenText Performance Engineering. This guide compares them fact by fact — cost, scripting, protocols, scale, and support — and covers a third option if neither extreme fits. - Keywords: JMeter vs LoadRunner, LoadRunner vs JMeter, OpenText Performance Engineering, Load Testing Tools Comparison, Apache JMeter, VuGen ### JMeter vs Locust: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/jmeter-vs-locust/ - Markdown: https://loadster.com/compare/jmeter-vs-locust/index.md - Description: JMeter vs Locust compared: scripting, protocols, distributed scale, and learning curve, with fact-based advice on which load testing tool fits your team. - Summary: JMeter and Locust are both free, open source load testing tools with opposite philosophies. JMeter is Java-based and GUI-driven with broad protocol support; Locust is a lightweight Python framework where tests are plain code. This guide compares them fact by fact, and covers a third option if neither tradeoff feels right. - Keywords: JMeter vs Locust, Locust vs JMeter, Open Source Load Testing Tools, Load Testing Tools Comparison, Python Load Testing, Apache JMeter ### k6 vs JMeter: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/k6-vs-jmeter/ - Markdown: https://loadster.com/compare/k6-vs-jmeter/index.md - Description: k6 vs JMeter compared: scripting, protocol coverage, scale, CI/CD, and learning curve, with fact-based advice on which load testing tool fits your team. - Summary: k6 and JMeter are the two most popular open source load testing tools, from two different eras. JMeter is the Java-based veteran with a desktop GUI and unmatched protocol breadth. k6 is the modern, code-first CLI tool built for developers and CI pipelines. This guide compares them fact by fact, and covers a third option if neither tradeoff feels right. - Keywords: k6 vs JMeter, JMeter vs k6, Open Source Load Testing Tools, Load Testing Tools Comparison, Grafana k6, Apache JMeter ### Locust vs k6: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/locust-vs-k6/ - Markdown: https://loadster.com/compare/locust-vs-k6/index.md - Description: Locust vs k6 compared: Python vs JavaScript scripting, per-machine efficiency, distributed scale, and CI/CD, with fact-based advice on which tool fits. - Summary: Locust and k6 are the two most popular code-first open source load testing tools. Locust is a Python framework where tests are plain classes; k6 is a Go-powered CLI tool scripted in JavaScript. This guide compares them fact by fact, and covers a third option if neither tradeoff feels right. - Keywords: Locust vs k6, k6 vs Locust, Python Load Testing, Open Source Load Testing Tools, Load Testing Tools Comparison ### Loadster vs BlazeMeter: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/loadster-vs-blazemeter/ - Markdown: https://loadster.com/compare/loadster-vs-blazemeter/index.md - Description: Loadster vs BlazeMeter compared: native platform vs hosted JMeter, real browser load testing, pricing, and which cloud load testing tool fits your team. - Summary: BlazeMeter and Loadster are both commercial cloud load testing platforms, but they're built on opposite ideas. BlazeMeter runs open source engines like JMeter, Gatling, and k6 on managed infrastructure; Loadster is a native platform with its own visual editor, Protocol Bots, real Chrome Browser Bots, and Playwright support. This guide offers a fact-based comparison so you can pick the right fit. - Keywords: Loadster vs BlazeMeter, BlazeMeter vs Loadster, BlazeMeter Alternative, BlazeMeter Alternatives, JMeter in the Cloud, Cloud Load Testing, Load Testing Tools Comparison ### Loadster vs JMeter: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/loadster-vs-jmeter/ - Markdown: https://loadster.com/compare/loadster-vs-jmeter/index.md - Description: Loadster vs Apache JMeter compared: scripting, real browser load testing, cloud scale, pricing — plus how to import your JMX test plans into Loadster. - Summary: Apache JMeter and Loadster are both capable load testing tools from very different eras. JMeter is the free, Java-based veteran with a desktop GUI and a huge plugin ecosystem. Loadster is a cloud platform with a visual script editor, real Chrome browsers, and managed load generation in 32 regions. This guide offers a fact-based comparison — and if you already have JMeter test plans, Loadster can import your JMX files directly. - Keywords: Loadster vs JMeter, JMeter vs Loadster, JMeter Alternative, JMeter Alternatives, Import JMX, JMeter Cloud, Load Testing Tools Comparison, Apache JMeter ### Loadster vs LoadRunner: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/loadster-vs-loadrunner/ - Markdown: https://loadster.com/compare/loadster-vs-loadrunner/index.md - Description: Loadster vs LoadRunner (OpenText Performance Engineering) compared: scripting, browser testing, licensing costs, and when a lighter platform fits. - Summary: LoadRunner (now sold as OpenText Performance Engineering) is the classic enterprise load testing suite, with deep protocol support, VuGen scripting, and licensing to match. Loadster is a modern cloud platform with a visual editor, real Chrome browsers, and transparent usage-based pricing. This guide offers a fact-based comparison so you can tell whether you need the enterprise suite or something faster and lighter. - Keywords: Loadster vs LoadRunner, LoadRunner vs Loadster, LoadRunner Alternative, LoadRunner Alternatives, OpenText Performance Engineering, LoadRunner Pricing, VuGen, Load Testing Tools Comparison ### Loadster vs Locust: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/loadster-vs-locust/ - Markdown: https://loadster.com/compare/loadster-vs-locust/index.md - Description: Loadster vs Locust compared: Python scripting, real browser load testing, distributed scale, pricing — plus how to import your locustfile into Loadster. - Summary: Locust and Loadster are both approachable load testing tools with very different foundations. Locust is a free, open source Python framework where tests are plain code. Loadster is a cloud platform with a visual script editor, real Chrome browsers, and managed load generation in 32 regions. This guide offers a fact-based comparison — and if you already have a locustfile, Loadster can import it directly. - Keywords: Loadster vs Locust, Locust vs Loadster, Locust Alternative, Locust Alternatives, Python Load Testing, Import Locustfile, Load Testing Tools Comparison ### Loadster vs k6: Load Testing Tools Compared (2026) - URL: https://loadster.com/compare/loadster-vs-k6/ - Markdown: https://loadster.com/compare/loadster-vs-k6/index.md - Description: Loadster vs k6 compared: scripting, real browser load testing, cloud scale, pricing, and CI/CD — with fact-based advice on which tool fits your team. - Summary: Loadster and k6 are both modern load testing tools, but they take different approaches. k6 is an open source, code-first CLI tool that developers run themselves. Loadster is a cloud platform with a visual script editor, real Chrome browsers, and managed infrastructure in 32 regions. This guide offers a fact-based comparison so you can pick the one that fits your team, your application, and your budget. - Keywords: Loadster vs k6, k6 vs Loadster, k6 Alternative, k6 Alternatives, Load Testing Tools Comparison, Grafana k6, Cloud Load Testing, Real Browser Load Testing ## FAQs > Here are some answers to Frequently Asked Questions about Loadster scripting, Protocol Bots, Browser Bots, and general load testing topics. ### Are dataset values unique across bot groups? - URL: https://loadster.com/faqs/dataset-values-unique-across-bot-groups/ - Markdown: https://loadster.com/faqs/dataset-values-unique-across-bot-groups/index.md - Description: When the same dataset is used by more than one bot group, each group gets its own copy, so unique-per-bot values are not unique across groups. - Summary: Not across groups. Dataset values are unique per bot within a single bot group, but each group works through its own copy of the dataset, so two groups using the same dataset can hand out the same value at the same time. Run a single group, or bind a different dataset to each group, if you need values to be unique everywhere. ### Authenticating with HTTP Basic or NTLM authentication - URL: https://loadster.com/faqs/set-http-basic-or-ntlm-authentication-for-browser-bots/ - Markdown: https://loadster.com/faqs/set-http-basic-or-ntlm-authentication-for-browser-bots/index.md - Description: How to supply HTTP Basic or NTLM authentication credentials to Loadster Browser Bots when load testing a site that requires them. ### Can AI Run Load Tests and Set Up Monitors? - URL: https://loadster.com/faqs/ai-assistant-run-load-tests/ - Markdown: https://loadster.com/faqs/ai-assistant-run-load-tests/index.md - Description: An AI assistant can write and play scripts, build load test scenarios, and set up monitors in Loadster, but launching a full load test stays your call. - Summary: An assistant can write and play scripts, build scenarios, and set up monitors, but it can't launch a full-scale load test. Playing a single bot is fine; starting a scenario at scale is a human decision. ### Connecting an AI Agent to the Loadster MCP Server - URL: https://loadster.com/faqs/connect-to-loadster-mcp-server/ - Markdown: https://loadster.com/faqs/connect-to-loadster-mcp-server/index.md - Description: Point your AI agent at the Loadster MCP server at api.loadster.com/mcp and connect with OAuth or a token. Setup steps for Claude, ChatGPT, and more. - Summary: Loadster's MCP server lives at https://api.loadster.com/mcp. Connect with OAuth when your client supports it, or use a Loadster MCP token. The AI agents manual has current steps for ChatGPT web, Codex desktop, and other clients. ### Cookies and variables between load test iterations - URL: https://loadster.com/faqs/cookies-and-variables-between-iterations/ - Markdown: https://loadster.com/faqs/cookies-and-variables-between-iterations/index.md - Description: Loadster has a setting for what to do with cache, cookies, and variables between iterations of the same bot. - Summary: There’s a setting for that. By default, the bot gets a fresh state for each iteration, so all cookies and variables from the previous iteration disappear. But you can change this behavior. ### Estimated and actual Loadster Fuel usage - URL: https://loadster.com/faqs/estimated-and-actual-fuel-usage/ - Markdown: https://loadster.com/faqs/estimated-and-actual-fuel-usage/index.md - Description: Sometimes a load test burns more (or less) Loadster Fuel than anticipated. Here are some reasons why. ### Evaluating a value or promise with Browser Bots - URL: https://loadster.com/faqs/evaluating-a-value-or-promise-inside-the-browser/ - Markdown: https://loadster.com/faqs/evaluating-a-value-or-promise-inside-the-browser/index.md - Description: Loadster's Evaluate Blocks can run custom JavaScript inside the bot's browser. Here's how to evaluate a simple value or promise. ### Excluding Browser Bot traffic from Google Analytics - URL: https://loadster.com/faqs/bot-traffic-is-showing-up-in-google-analytics/ - Markdown: https://loadster.com/faqs/bot-traffic-is-showing-up-in-google-analytics/index.md - Description: How to configure Loadster and Google Analytics so that your bot traffic doesn't show up in the analytics. ### Generating a JWT to use in a load test - URL: https://loadster.com/faqs/generating-a-jwt/ - Markdown: https://loadster.com/faqs/generating-a-jwt/index.md - Description: Many back-end APIs expect a JSON Web Token (JWT) as a way of authenticating requests or passing claims between systems. Here's how to make one in Loadster. ### Generating random strings, numbers, and UUID/GUID - URL: https://loadster.com/faqs/generating-random-string-or-uuid/ - Markdown: https://loadster.com/faqs/generating-random-string-or-uuid/index.md - Description: Loadster has easy ways to generate random strings, numbers, or UUID/GUID for your load test scripts. - Summary: Sometimes it’s necessary to generate a random string, number, or UUID/GUID in your load test script. You can do this with a function call from an expression. ### How many bots are required for a load test - URL: https://loadster.com/faqs/calculating-v-users-needed-for-a-load-test/ - Markdown: https://loadster.com/faqs/calculating-v-users-needed-for-a-load-test/index.md - Description: How many bots does your load test require? Here's a quick formula to calculate the number of bots required for a load test by working backwards. - Summary: Let’s say you know how much total traffic or transactions you need to simulate in a time period. How do you work backwards to estimate how many concurrent bots it will take to get the job done? ### How Many Bots or Virtual Users Can Loadster Run? - URL: https://loadster.com/faqs/maximum-concurrent-bots-or-virtual-users/ - Markdown: https://loadster.com/faqs/maximum-concurrent-bots-or-virtual-users/index.md - Description: Loadster customers have run 170,000+ concurrent real Chrome browsers, and Protocol Bot capacity goes well into the millions. Here's how it scales. - Summary: Loadster customers have run load tests with over 170,000 concurrent real Chrome browsers, and Protocol Bot capacity goes well into the millions. There's no fixed platform cap; practical scale depends on regions and cloud capacity. ### Ignoring untrusted TLS/SSL/HTTPS certificate errors - URL: https://loadster.com/faqs/ignore-untrusted-ssl-tls-certificate-errors/ - Markdown: https://loadster.com/faqs/ignore-untrusted-ssl-tls-certificate-errors/index.md - Description: How to configure Loadster to ignore self-signed or untrusted TLS/SSL certificates when load testing a site on a staging or development environment. - Summary: Loadster normally refuses to talk to sites with untrusted or self-signed certificates, like a normal browser would. If it’s your own site and you want to trust it, you can override this behavior. ### Including one Loadster script in another - URL: https://loadster.com/faqs/including-scripts-for-reuse/ - Markdown: https://loadster.com/faqs/including-scripts-for-reuse/index.md - Description: Code reuse is a good thing, and that includes test scripts. Here's how you can include one test script in another with Loadster. ### Including or excluding errors in response times - URL: https://loadster.com/faqs/exclude-errors-from-response-times/ - Markdown: https://loadster.com/faqs/exclude-errors-from-response-times/index.md - Description: You might want to include or exclude errors from response time calculations. Here's how to do that in Loadster. - Summary: Sure! There’s a global setting to do exactly this. ### Latency vs Response Time: What's the Difference? - URL: https://loadster.com/faqs/latency-vs-response-time/ - Markdown: https://loadster.com/faqs/latency-vs-response-time/index.md - Description: Latency is the network delay before data starts arriving; response time is the full wait for a complete response. Here's how the two differ in load testing. - Summary: Latency and response time are often used interchangeably, but they measure different things. The distinction matters when you're deciding what to optimize. ### Limiting the number of bot iterations in a load test - URL: https://loadster.com/faqs/limiting-total-iterations-in-a-load-test/ - Markdown: https://loadster.com/faqs/limiting-total-iterations-in-a-load-test/index.md - Description: In Loadster, bots normally repeat your script until time runs out. Here's how to set an iteration limit so bots stop after a specific number of runs. - Summary: Normally, bots will continue to run your script over and over as long as there is time remaining in the test. However, you can set an iteration limit to make them stop after a set number of iterations. ### Load test reporting artificially high response times - URL: https://loadster.com/faqs/load-test-reporting-high-response-times/ - Markdown: https://loadster.com/faqs/load-test-reporting-high-response-times/index.md - Description: If you're running a load test and Loadster reports high response times, but you access the site yourself and it's fast, there are a few things it might be. - Summary: Here are a few reasons Loadster might report higher response times in a load test than you're experiencing on the site. ### Load test reporting higher network throughput - URL: https://loadster.com/faqs/load-test-throughput-bytes-higher-than-expected/ - Markdown: https://loadster.com/faqs/load-test-throughput-bytes-higher-than-expected/index.md - Description: Why Loadster might report higher network throughput than your hosting provider. Common reasons for the discrepancy and how to interpret the numbers. - Summary: Common reasons why Loadster may report higher bandwidth usage than what your server or hosting provider measures. ### Load Testing with Claude, ChatGPT, and AI Assistants - URL: https://loadster.com/faqs/using-ai-for-load-testing/ - Markdown: https://loadster.com/faqs/using-ai-for-load-testing/index.md - Description: Yes. Connect Claude, ChatGPT, Cursor, or another AI assistant to Loadster over MCP, and it can write scripts, build load tests, and read your results. - Summary: Loadster runs an MCP server, so assistants like Claude, ChatGPT, and Cursor can connect to your account and write scripts, build load test scenarios, and read results, while you decide what runs. ### Make Browser Bot traffic show up in Google Analytics - URL: https://loadster.com/faqs/bot-traffic-is-not-showing-up-in-google-analytics/ - Markdown: https://loadster.com/faqs/bot-traffic-is-not-showing-up-in-google-analytics/index.md - Description: If your Browser Bot traffic isn't showing in Google Analytics, and you want it to, here's How to configure Loadster and Google Analytics. - Summary: How to configure Loadster and Google Analytics so that your bot traffic shows up in the analytics. ### Manually setting a cookie in your script - URL: https://loadster.com/faqs/manually-set-a-cookie/ - Markdown: https://loadster.com/faqs/manually-set-a-cookie/index.md - Description: Loadster handles most cookies automatically, but occasionally you might need to set one yourself. Here's how to set a cookie in your Loadster script. - Summary: Loadster handles most cookies automatically, but sometimes you need to manually set a cookie yourself. An example of when this might be necessary is if you’re trying to piggyback on existing sessions without actually logging in. ### Page Object Model (POM) in Playwright - URL: https://loadster.com/faqs/playwright-page-object-model/ - Markdown: https://loadster.com/faqs/playwright-page-object-model/index.md - Description: Loadster Playwright scripts are a single file, but you can still use the Page Object Model (POM) and other organization patterns. Here's how. - Summary: A Loadster Playwright script is one self-contained file, so it can't import page objects from other files. You can still use the Page Object Model (POM) by defining your page classes in the same file as your test. ### Parsing and validating a JSON response in a load test - URL: https://loadster.com/faqs/parse-a-json-response/ - Markdown: https://loadster.com/faqs/parse-a-json-response/index.md - Description: How to parse and validate JSON responses in a Loadster test script, to verify your API returns the expected data under heavy traffic. - Summary: When you’re testing a JSON API, don’t just trust the HTTP 2xx responses to mean that everything’s working as expected. Add validation to look at the response bodies coming back and make sure they’re valid JSON and contain the right data. ### Parsing and validating an XML response in a load test - URL: https://loadster.com/faqs/parse-an-xml-response/ - Markdown: https://loadster.com/faqs/parse-an-xml-response/index.md - Description: Validating an XML response in a load test is a way to validate the server response is what you expected. Here's how to do it in Loadster. - Summary: When load testing XML web services (like SOAP, XML-RPC, and some RESTful services for example), it’s a good idea to parse the responses to make sure they are well-structured and contain the expected data. ### Passing Loadster variables into the browser - URL: https://loadster.com/faqs/passing-loadster-variables-to-the-browser/ - Markdown: https://loadster.com/faqs/passing-loadster-variables-to-the-browser/index.md - Description: How to expose dataset variables and bot context to JavaScript running inside the page with Browser Bots. - Summary: Use browser.setVariable() in a code block to push a value onto the window object, so subsequent eval blocks and the page itself can read it without any string-building. ### Playing scripts against a site on a private network - URL: https://loadster.com/faqs/playing-a-script-on-a-private-network/ - Markdown: https://loadster.com/faqs/playing-a-script-on-a-private-network/index.md - Description: Normally, Loadster scripts play from the public cloud. Run your own engines as script players if you need to hit a site on a private network. - Summary: If your site is on a private network that’s unreachable from the rest of the internet, you’ll need to self-host a Loadster Engine on your own network. ### Range sliders, color pickers, and other HTML inputs - URL: https://loadster.com/faqs/manipulating-range-sliders-and-other-unusual-inputs/ - Markdown: https://loadster.com/faqs/manipulating-range-sliders-and-other-unusual-inputs/index.md - Description: How to control range sliders, color pickers, and other HTML inputs with Loadster Browser Bots using JavaScript Evaluate Blocks. ### Real Browsers vs Headless Browsers in Load Testing - URL: https://loadster.com/faqs/real-browsers-vs-headless/ - Markdown: https://loadster.com/faqs/real-browsers-vs-headless/index.md - Description: Loadster's Browser Bots run real Chrome in headless mode: a full browser engine with real rendering and JavaScript, just without a visible window. - Summary: Headless doesn't mean fake. Here's what headless browsers actually are, how they differ from protocol-level simulation, and what Loadster's Browser Bots run. ### Requests per Second vs TPS vs Concurrent Users - URL: https://loadster.com/faqs/rps-tps-concurrent-users/ - Markdown: https://loadster.com/faqs/rps-tps-concurrent-users/index.md - Description: Requests per second, transactions per second, and concurrent users measure different things. Here's how they relate and how to convert between them. - Summary: RPS counts HTTP requests, TPS counts completed transactions, and concurrent users counts simultaneous people. Load test targets only make sense when you know which one you're talking about. ### Resizing or switching windows/tabs with Browser Bots - URL: https://loadster.com/faqs/switch-or-resize-browser-windows/ - Markdown: https://loadster.com/faqs/switch-or-resize-browser-windows/index.md - Description: Loadster's browser bots start with a single window with a viewport size of 1280x720 pixels, but you can change that. ### Scripting for iframe elements with Browser Bots - URL: https://loadster.com/faqs/interacting-with-elements-in-an-iframe/ - Markdown: https://loadster.com/faqs/interacting-with-elements-in-an-iframe/index.md - Description: Loadster's Browser Bots support special CSS-style selectors for interacting with an input or other element within an iframe. ### Single Sign On (SSO) Support - URL: https://loadster.com/faqs/sso-saml-single-sign-on/ - Markdown: https://loadster.com/faqs/sso-saml-single-sign-on/index.md - Description: Loadster supports SAML2 for Single Sign-On (SSO). This is available with annual plans and custom plans upon request and we'd be happy to help you set it up. - Summary: Loadster supports SAML2 SSO with annual and custom plans. ### Stopping a load test script when an error occurs - URL: https://loadster.com/faqs/stop-on-error/ - Markdown: https://loadster.com/faqs/stop-on-error/index.md - Description: Loadster has an option to immediately stop playing a script if validation fails or some other error happens. Otherwise, the script can keep playing. - Summary: A Loadster bot typically keeps playing a script even if validation fails on a step or an error occurs, but you can change that. ### Tracking custom timings in a load test script - URL: https://loadster.com/faqs/setting-custom-timers-in-a-load-test/ - Markdown: https://loadster.com/faqs/setting-custom-timers-in-a-load-test/index.md - Description: Loadster automatically measures most response times, but you can also add custom timers to measure specific transactions. - Summary: You can set custom timers to measure key transactions. ### Using a custom hosts file for load testing - URL: https://loadster.com/faqs/custom-hosts-file-for-load-testing/ - Markdown: https://loadster.com/faqs/custom-hosts-file-for-load-testing/index.md - Description: How to override DNS hostnames in a Loadster load test, simulating a custom hosts file to point scripts at a staging or alternate environment. - Summary: If you’re load testing an alternate environment that’s not available with a normal DNS lookup, read on for how to simulate a custom hosts file. ### What Happened to Speedway? It Merged Into Loadster - URL: https://loadster.com/faqs/monitoring-with-speedway/ - Markdown: https://loadster.com/faqs/monitoring-with-speedway/index.md - Description: Speedway, our standalone site monitoring product, has been merged back into Loadster. Its monitoring capabilities now live in Site & API Monitoring. - Summary: Speedway was our standalone site monitoring product. Its capabilities have been merged back into Loadster, so all your monitoring now happens in one place. ### What Is a Good Apdex Score? - URL: https://loadster.com/faqs/good-apdex-score/ - Markdown: https://loadster.com/faqs/good-apdex-score/index.md - Description: An Apdex score above 0.85 is generally considered good. Here's how Apdex is calculated, what the thresholds mean, and how it relates to load test results. - Summary: Apdex condenses response times into a single satisfaction score between 0 and 1. Here's how it's calculated, what counts as a good score, and how to get similar insight from percentiles. ### What Is a Load Generator? Engines and Cloud Regions - URL: https://loadster.com/faqs/load-generator/ - Markdown: https://loadster.com/faqs/load-generator/index.md - Description: A load generator is the machine that runs simulated users during a load test. In Loadster, load generation comes from cloud regions or self-hosted engines. - Summary: A load generator is the infrastructure that runs your simulated users and fires traffic at the system under test. In Loadster, that's a cloud region or a self-hosted Loadster Engine. ### What Is a Performance Bottleneck in Load Testing? - URL: https://loadster.com/faqs/performance-bottleneck/ - Markdown: https://loadster.com/faqs/performance-bottleneck/index.md - Description: A performance bottleneck is the one resource that limits your whole system's capacity under load. Here's how bottlenecks show up in load test results. - Summary: A performance bottleneck is the component that saturates first and caps your whole system's capacity. Load testing exists largely to find them before your users do. ### What Is Think Time (Wait Time) in Load Testing? - URL: https://loadster.com/faqs/think-time-wait-time/ - Markdown: https://loadster.com/faqs/think-time-wait-time/index.md - Description: Think time, called wait time in Loadster, is the pause between a simulated user's actions. Realistic wait times are what make load test results trustworthy. - Summary: Think time (or wait time) is the pause between a simulated user's actions, standing in for reading, typing, and deciding. Getting it wrong skews everything a load test tells you. ### What Is Throughput in Load Testing? - URL: https://loadster.com/faqs/throughput-in-load-testing/ - Markdown: https://loadster.com/faqs/throughput-in-load-testing/index.md - Description: Throughput is the rate of work a system completes under load, measured in requests, pages, or bytes per second. Here's how to read it in load test results. - Summary: Throughput is how much work your system completes per unit of time under load. Watching how it responds as load increases tells you where your capacity ceiling is. ### What p50, p90, p95, and p99 Response Times Mean - URL: https://loadster.com/faqs/response-time-percentiles/ - Markdown: https://loadster.com/faqs/response-time-percentiles/index.md - Description: Percentile response times like p50, p80, p90, p95, and p99 tell you what most users actually experience in a load test, unlike averages which hide outliers. - Summary: Averages hide slow outliers. Percentile response times (p50, p80, p90, p95, p99) tell you what your fastest and slowest users actually experience under load. ### Where the script traffic originates when scripting - URL: https://loadster.com/faqs/where-does-script-traffic-originate/ - Markdown: https://loadster.com/faqs/where-does-script-traffic-originate/index.md - Description: Normally, Loadster plays scripts from the public cloud. Here's how to control where the script traffic originates from when you run scripts in the editor. - Summary: If you don't specify a region or engine, Loadster will play your scripts from a random engine. Here's how to control where the traffic originates if you need a specific origin. ### Whitelist IP addresses for a load test - URL: https://loadster.com/faqs/whitelist-load-test-ip-addresses/ - Markdown: https://loadster.com/faqs/whitelist-load-test-ip-addresses/index.md - Description: Is your firewall or load balancer blocking traffic based on IP address? Here's how to get Loadster's IP addresses so you can whitelist them. - Summary: Some load balancers and firewalls watch for an onslaught of traffic from the same IP, and block it. When running a load test in these environments, you may need to whitelist certain IP addresses. ### Why is Loadster saying cloud capacity was exceeded? - URL: https://loadster.com/faqs/load-test-cloud-capacity/ - Markdown: https://loadster.com/faqs/load-test-cloud-capacity/index.md - Description: When you run a load test, Loadster launches instances in your choice of cloud regions, but there may be times when capacity is exceeded in a region. - Summary: Occasionally, Loadster may refuse to launch a load test in your region(s) of choice, if those regions have previously been shown to lack capacity for the number of bots your test requires. ### Writing Playwright scripts in TypeScript - URL: https://loadster.com/faqs/playwright-typescript-support/ - Markdown: https://loadster.com/faqs/playwright-typescript-support/index.md - Description: Loadster Playwright scripts support both JavaScript and TypeScript. You can paste in a .ts or .js Playwright test and it just works. - Summary: Loadster Playwright scripts support both JavaScript and TypeScript. The Playwright Test runner compiles TypeScript automatically, so type annotations and interfaces work with no extra setup. ## Changelog > Recent product updates, new features, and bug fixes shipped each month. Full changelog history is available at https://loadster.com/changelog/. ### 2026.08 - URL: https://loadster.com/changelog/2026-08/ - Description: In August 2026, Loadster got an MCP server so AI agents can build and debug your scripts, an interactive homepage launcher, and faster script loading. ### 2026.07 - URL: https://loadster.com/changelog/2026-07/ - Description: In July 2026, Playwright scripts gained TypeScript support, load tests started capturing Playwright traces, and browser code blocks learned to use locators. ### 2026.06 - URL: https://loadster.com/changelog/2026-06/ - Description: In June 2026, Loadster added JMeter, k6, and Locust script importers, more performance stats per bot group, and a mobile-friendly dashboard. ### 2026.05 - URL: https://loadster.com/changelog/2026-05/ - Description: In May 2026, browser scripts got more powerful Playwright-style locators. We also added social login and registration, and Asia got a wildcard cloud region. ### 2026.04 - URL: https://loadster.com/changelog/2026-04/ - Description: In April 2026, Loadster added page performance scoring in load tests and monitoring, optional TOTP 2FA support, and better support for Evaluate Block variables. ### 2026.03 - URL: https://loadster.com/changelog/2026-03/ - Description: In March 2026, monitoring maintenance windows got the ability to pause monitors, and Playwright scripts got better timeout and tracing capabilities. ### 2026.02 - URL: https://loadster.com/changelog/2026-02/ - Description: February 2026: Monitors gained page timing metrics (TTFB, LCP, FCP, CLS), browser traces added headers, and the home dashboard got a major redesign. ### 2026.01 - URL: https://loadster.com/changelog/2026-01/ - Description: January 2026: Monaco-based code editor with autocomplete, Playwright scripts got dataset variable support, and monitoring summary emails got a major upgrade. ### 2025.12 - URL: https://loadster.com/changelog/2025-12/ - Description: In December 2025, Playwright Test scripting became generally available, and monitors gained performance threshold evaluation as a pass/fail criteria. ### 2025.11 - URL: https://loadster.com/changelog/2025-11/ - Description: In November 2025, we shipped a batch of improvements and bug fixes across the dashboard, script editor, test reports, and monitor summaries. ### 2025.10 - URL: https://loadster.com/changelog/2025-10/ - Description: In October 2025, load test scenarios gained flexible multi-stage ramp patterns, live load adjustment, and three new wildcard cloud regions. ### 2025.09 - URL: https://loadster.com/changelog/2025-09/ - Description: In September 2025, Playwright Test support entered beta, and we improved test report exports, date formatting, and multibyte character handling.