FAQs

What is Loadster Fuel and how does it work?

Loadster Fuel is the usage currency for load testing and site monitoring. You buy fuel in packs, and bots burn it while they run.

It is not a seat license. Editing scripts, designing scenarios, and reading reports don’t burn any. You only pay for the bots that actually generate traffic.

Every new account starts with 50 free units. No credit card required.

How Loadster Fuel usage is calculated

Usage is roughly:

fuel ≈ duration × launched bots × bot type

Duration is how long the bots run. Launched bots is how many bots you start. Bot type is a multiplier:

A Protocol Bot running for one hour burns 1 unit of fuel. 100 Protocol Bots running for 30 minutes burn 50 units of fuel, and the same test with Browser Bots burns 200 units of fuel.

You can mix bot types in one test. Each bot group burns fuel at its own multiplier.

If you request larger clusters for a bot group on a CPU-heavy site, that group burns 1.25× as much fuel at 2X cluster scaling, or 1.75× at 4X.

The fuel calculator on the Loadster Fuel page does this math as you change duration, bot count, and bot type. For monitoring, it uses the same formula with one bot per cycle and whatever schedule you pick.

How Loadster Fuel compares to VU-hours

VU-hours (virtual user hours) are the unit a lot of load testing tools use: one virtual user running for one hour.

In Loadster, one unit of fuel is one Protocol Bot running for one hour. So for Protocol Bots, 1 unit of fuel ≈ 1 VU-hour.

Browser Bots and Playwright scripts are still one bot (one virtual user) each, but they burn 4 units of fuel per bot-hour. If you are converting a VU-hour quote from another tool, count Protocol Bots 1:1 and multiply real browser bots by 4.

Loadster doesn’t sell a separate VU-hour product. Your fuel balance is those bot-hours after the bot-type multiplier.

Why Browser Bots and Playwright scripts burn more fuel

Browser Bots and Playwright scripts each drive a real Chrome browser. That takes more cloud compute than Protocol Bots, which send HTTP requests without a browser.

The 4× multiplier is there because real browsers cost more to run, not because we think they are four times more valuable. Protocol Bots are the economical choice for APIs and high-volume HTTP traffic. Browser Bots and Playwright scripts are the better fit when you need real browser load testing: JavaScript, page resources, and front-end timing.

You can mix them. A typical pattern is Browser Bots or Playwright scripts on the important user flows, with Protocol Bots adding background traffic.

How free Loadster Fuel works

Signing up gives you 50 units of fuel. That is enough for a handful of short tests, such as four 30-minute tests with 25 Protocol Bots each. No credit card, no commitment.

Load tests on free fuel can run up to 25 bots in up to 3 bot groups, from North America. Once you add fuel or a plan, you can run larger tests from any cloud region.

When the 50 units run out, you can buy pay-as-you-go fuel or switch to the Team plan. Until then, you can still edit scripts, save scenarios, and look at reports. Running out of fuel pauses new load tests and fuel-based monitor cycles; it does not delete your data.

The 50 free units are a starter amount, not a monthly allowance. They do not refill on their own.

Loadster Fuel versus the Team plan

Pay-as-you-go fuel starts at $97 for 1,000 units. There is no subscription, fuel you buy never expires, and bigger packs cost less per unit.

The Team plan is one flat price instead, with no fuel to keep track of. It covers load tests of up to 1,000 Browser Bots and 10,000 Protocol Bots for 240 test hours a year (20 a month on monthly billing), plus monitoring and team features. Tests bigger than the plan allows, or tests after the hours run out, can still run with fuel, which costs 30% less on the Team plan.

Estimated versus actual Loadster Fuel usage

The dashboard estimates fuel from the bots, bot types, and durations in your scenario. Actual usage is based on how long the bots really ran, which can be a bit more or less than the estimate.

If a test overruns because bots finish a long iteration after time is up, it can burn extra fuel. If you stop a test early, it burns less. See estimated and actual fuel usage for the usual reasons.