Your site has a breaking point.
Let's find it before your users do.
Don't crash under peak traffic! Load test your web application with thousands of bots to optimize performance, control costs, and prevent downtime.
Start testing for freeAutomate real Chrome browsers
or multithreaded HTTP clients
Browser Bots control real headless Chrome browsers, for the most realistic load testing possible. Automating thousands of real browsers is the best way to stress test dynamic web apps and modern websites.
Protocol Bots execute scripted HTTP/S requests against your website or API. Testing at the protocol layer is the most cost-effective way to load test your APIs and static sites.
Simulate traffic spikes and floods
for websites, web apps, and APIs
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Website Load Testing
Record scripts with the free Loadster Recorder browser extension.
Play them back with thousands of bots from 24 cloud regions across the globe.
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Web App Load Testing
Loadster is a powerful way to test modern web applications.
Automatically navigate complex authentication flows, execute client-side JavaScript, and implement your own control flow with code blocks.
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API Load Testing
Load test any kind of HTTP API at the protocol layer -- including REST, GraphQL, JSON-RPC, & XML-RPC APIs.
Import your scripts from Postman or OpenAPI/Swagger.
Accelerate your load testing
with a faster feedback loop
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Rapidly create your test scripts
Record load test scripts right in your browser, with the Loadster Recorder extension for Chrome or Firefox. Just step through your site like a real user would while Loadster records every step into a script. After recording, play your script back in real time, and edit it to perfection with Loadster's interactive script editor.
It's simple to add custom validation and capture server responses to reuse later in the script. Not powerful enough for you? Try JavaScript Code Blocks for advanced control flow, looping, and conditionals.
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Launch distributed cloud tests in seconds
Configure your test scenario with groups of bots in regions of your choosing, running your scripts, ramping the load up and down, to simulate the geographically distributed traffic you see in the real world.
Loadster's got what you need to run globally distributed cloud tests with minimal setup. No need to deploy your own instances to run test infrastructure! In about 90 seconds, Loadster can launch tens of thousands of bots across hundreds of cloud instances in regions of your choosing.
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Analyze results with quick reporting
While a load test runs, Loadster gives you realtime metrics on response times (average and percentile), network and transaction throughput, errors, and more.
After it finishes, the same data is instantly available in a test report you can hold on to or share with your team.
The metrics and report data inform you how your site handled the traffic, what kind of performance your real users can expect when the site's under a similar amount of load, and where the hot spots and bottlenecks might be.
Load testing for web apps
built to move fast
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Speedy script recording
Record scripts right in your browser with the free Chrome or Firefox extension. Or add steps manually.
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Browser based editing
Add steps, edit them, and tweak your script to perfection. All in your web browser.
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Rapid script feedback
Play scripts from your web browser, and watch in real time as each step runs. Repeat as necessary!
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Detailed diagnostics
After your script runs, view the full HTTP request and response from every step, both headers and body.
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Fully managed cloud
No need install any infrastructure! Loadster spins up fully managed cloud instances in about 90sec.
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Live stream test results
As a test runs, watch 10+ charts in real time. Monitor response times, throughput, errors, and more.
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Automatic test reports
Loadster generates a full test report with charts and tables after every test. No more manual reporting!
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Team collaboration
Anyone on your team can create scripts, run tests, and share results. Make scalability a team effort!
Test from 24 global cloud regions
or your own self-hosted engines
Loadster can launch thousands of bots from your choice of cloud regions in 1-3 minutes. You can also self-host your engines to test privately hosted applications that aren't reachable from the cloud.

Flexible pricing
to fit the way you test
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Loadster Fuel
Pay as you go, from $119 per 1000 bot hours
Buy fuel and run load tests in any of 24 Loadster Cloud regions. No commitment. Simply purchase more fuel when you run out!
View Loadster Fuel Pricing -
Monthly Plans
Run tests anytime, from $399 a month
Run frequent tests at a predictable price. Load test anytime without burning fuel. The best option if you load test regularly!
View Monthly Plan Pricing
Move fast
don’t crash
Ready to reduce the risk of site crashes?
Load testing gives you the confidence your site can handle it.
The load testing tool of choice
for some pretty awesome people