Your site has a breaking point. Load test to find it before your users do.
Create powerful test scripts with Playwright, Browser Bots, or Protocol Bots. Launch thousands of concurrent bots from 32 AWS and GCP cloud regions. Reuse the same scripts for load testing, stress testing, and synthetic monitoring.
Load testing + synthetic monitoring = high availability. Prepare for heavy traffic, react quickly to problems.
Loadster is a cloud-based performance engineering platform that uses the same scripts for load testing, stress testing, and synthetic monitoring, so you can proactively test and monitor your site's key pages and critical flows.
Load testing your site will determine ahead of time how it will handle heavy load in a real high-traffic event. Discovering your site's breaking point and then eliminating scalability bottlenecks will make your site more resilient and far less likely to crash when a surge of real traffic hits.
Monitoring your site's critical flows around-the-clock is just as important. Even high-performance sites can suffer unplanned downtime. Active site monitoring, with bots constantly testing your site's most important user journeys, will help you detect problems and react to them before your users are impacted.
Loadster's combination of proactive load testing and reactive monitoring is just what you need for high-availability websites, web apps, and APIs.
Load Testing
ProactiveLoad test your site with thousands of concurrent bots to prepare for heavy traffic. Find the breaking point, identify scalability bottlenecks, and optimize performance to prevent site crashes under peak load.
Find your site's breaking point before peak traffic catches you off guard.
Synthetic Monitoring
ReactiveMonitor your site 24×7×365 with bots to detect problems quickly and ensure your site stays fast, functional, and always available. Bots test your site at all hours from multiple locations around the world.
Detect downtime and other problems before real users are impacted.
Automate real headless Chrome browsers or lightweight HTTP clients. Your choice of Playwright, Browser Bots, or Protocol Bots.
Browser Bots
Record scripts in your browser with Loadster's free extension and edit them visually. Add JavaScript if necessary. Browser Bots automate real headless Chrome browsers for realistic web application testing with a minimal learning curve.
4X
Protocol Bots
Protocol Bots execute scripted HTTP/S requests against your API or static website. Testing at the protocol layer is cost-effective and easily scales to hundreds of thousands of concurrent bots, and is ideal for testing HTTP APIs at scale.
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Playwright
Run your Playwright Test scripts at scale through Loadster's cloud. Ideal for teams already using Playwright or who want programmatic control with an open source testing framework, combined with Loadster's cloud scaling and reporting.
4X
Load testing with your favorite AI assistant. Control Loadster with Claude, ChatGPT, Codex, Cursor, VS Code, and other MCP clients.
Describe the flow you want to test in plain language. Your agent writes the script, plays it with a single bot until every step passes, and builds a load test scenario that's ready to launch.
- Scripts that actually work. Playwright, Browser Bot, or Protocol Bot scripts, played and fixed until they work.
- Scenarios from a sentence. Bot counts, cloud regions, and ramp-up patterns, straight from your description.
- Reports and incidents, explained. Your agent reads the test report or a failed monitor cycle and helps work out what went wrong.
- You: write a loadster script for our checkout on staging.acmeoutfitters.com in a real browser. search for trail shoes, add one to the cart, check out as a guest. then set up a load test with 1000 bots from virginia and london
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get_documentationcreate_script"Guest Checkout" 7 steps from the homepage to the order confirmation -
play_scriptget_play_statusStep 5 failed because “Continue as guest” never became clickable -
get_screenshotThe screenshot shows a cookie banner covering the button -
update_scriptplay_scriptget_play_statusDismissed the banner first, and all 7 steps passed in 9.2 seconds -
list_enginescreate_scenario"Guest checkout, 1,000 browsers" Saved to your Staging project -
Ready to go. Launching is your call, since a test this size runs unattended and uses Loadster Fuel. When it finishes, I'll read the report and help you analyze the results.
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ScenarioGuest checkout, 1,000 browsers
- 500 Browser Bots
- N. America - Virginia
- 500 Browser Bots
- Europe - United Kingdom
- Ramp
- Up in 60s, hold 5 min
Launch Test
Connect to the Loadster MCP server
Install the Loadster plugin, which adds the MCP server and a few load testing skills:
/plugin marketplace add loadster/loadster-mcp
/plugin install loadster@loadsterThen run /mcp, choose loadster, and approve the Loadster OAuth connection in your browser. To add just the server instead, run claude mcp add --transport http loadster https://api.loadster.com/mcp.
In Claude, open Settings → Connectors, choose Add custom connector, and paste the Loadster MCP URL:
https://api.loadster.com/mcpChoose Connect and approve the Loadster connection in your browser. This works for claude.ai too.
Loadster is an official ChatGPT plugin. Open it, choose Install plugin, and approve the Loadster connection when prompted:
Then mention @Loadster in a conversation. On a Business or Enterprise workspace, an admin may need to make it available first.
Install the Loadster plugin from the Plugins tab in the Codex desktop app, or run /plugins in the Codex CLI. To add the MCP server directly instead:
codex mcp add loadster --url https://api.loadster.com/mcp
codex mcp login loadsterThe IDE extension doesn’t support plugins, so it uses this configuration, which the desktop app and CLI share.
Add Loadster to .cursor/mcp.json in your project, or use the one-click install link:
{
"mcpServers": {
"loadster": { "url": "https://api.loadster.com/mcp" }
}
}Approve the Loadster OAuth connection in your browser the first time Cursor connects.
Any other MCP client that supports remote servers over Streamable HTTP connects to the same URL, with OAuth or a personal access token.
https://api.loadster.com/mcpLoad test on demand from 32 AWS and GCP cloud regions. Monitor continuously from 8 locations across 5 continents.
Performance engineering results with less time and effort. Loadster makes your team faster with browser-based scripting, fully managed infrastructure, live metrics, and automatic reporting.
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Script Recording
Record scripts right in your browser with the free Chrome or Firefox extension. Or add steps manually, if you prefer.
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Quick Editing
Edit your scripts and replay them with a single bot until it works perfectly. Choose between the graphical and text editor.
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Instant Playback
As you play scripts from your web browser, watch the results in real time as each step runs. Edit and repeat as necessary!
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Diagnostic Traces
After your script runs, you can inspect requests, responses, screenshots, and errors from every step.
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Managed Cloud
No need install anything or set up test infrastructure! Loadster spins up fully managed cloud instances in about 2-3 minutes.
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Live Results
As each load test runs, keep an eye on the real-time graphs and tables. Observe your site's response times, throughput, and errors.
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Automatic Reports
Loadster automatically generates a full test report with charts and tables after each test. No more tedious manual reporting.
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Team Collaboration
Invite your colleagues, and anyone on your team can create scripts, run tests, and share results. Make scalability a team effort!
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AI Agents & MCP
Connect Claude, ChatGPT, or Cursor to Loadster. Your agent writes and plays scripts, wires datasets, and builds scenarios.
Loadster scales with your testing and your budget. Choose between flexible pay-as-you-go and predictable subscription pricing.
Monthly Fuel Plans
Starting at $77 a month
Subscribe to a monthly plan to automatically add fuel every month at a discount. Unused fuel rolls over as long as you keep the plan.
Check Plan PricingPay As You Go
Starting at $97 for 1000 units
Purchase as much Loadster Fuel as you need for your load testing and monitoring. No commitment, just buy it when you need it.
Check Fuel PricingLoadster has optimized the performance, scalability, and uptime of thousands of sites. We're proud to be a testing platform of choice to elite teams.
Move fast
Don’t crash
Ready to cut your risk of downtime? Load test to prevent crashes. Monitor to react quickly.
