Stresix

Stresix MCP server

Load test your app from Claude Code, Cursor or any MCP client before you launch.

Tell your agent "load test this app before I launch". Stresix builds your GitHub repo or Docker image on a fresh cloud server, ramps simulated users at it from a second server in the same datacenter, and hands the report back to the agent: what ran out first, p95 latency, error rate and what server size to run it on. No k6 script to write.

The server is hosted at https://stresix.com/mcp (MCP over Streamable HTTP). Nothing to install.

Setup

1. Sign in at stresix.com with GitHub, Google or email.
2. Open Settings, then Keys for agents, and create a key. It is shown once.
3. Add the server to your client.

Claude Code

claude mcp add --transport http stresix https://stresix.com/mcp \
  --header "Authorization: Bearer YOUR_STRESIX_KEY"

Cursor (~/.cursor/mcp.json, or .cursor/mcp.json in a project)

{
  "mcpServers": {
    "stresix": {
      "url": "https://stresix.com/mcp",
      "headers": { "Authorization": "Bearer YOUR_STRESIX_KEY" }
    }
  }
}

Windsurf (~/.codeium/windsurf/mcp_config.json)

{
  "mcpServers": {
    "stresix": {
      "serverUrl": "https://stresix.com/mcp",
      "headers": { "Authorization": "Bearer YOUR_STRESIX_KEY" }
    }
  }
}

VS Code (.vscode/mcp.json)

{
  "servers": {
    "stresix": {
      "type": "http",
      "url": "https://stresix.com/mcp",
      "headers": { "Authorization": "Bearer YOUR_STRESIX_KEY" }
    }
  }
}

Tools

Tool	What it does
start_load_test	Builds and load tests a GitHub repo URL or Docker image. Takes the port, up to 10 GET paths, a branch, env vars the app needs to boot and the run size.
get_test_status	Building, starting servers, or running with live users, requests per second, p95 and error rate.
get_test_report	The verdict when the run is done: users held, p95, error rate, what ran out first, what to change and the server size to pick.

Pricing

Run	Load	Target server	Cost
Lite	500 users, 4 minutes	2 vCPU / 4 GB	Free once per person
Standard	2,500 users, 10 minutes	4 vCPU / 8 GB	1 credit
Massive	10,000 users, 15 minutes	8 vCPU / 16 GB	3 credits

Credits come in packs: $10 for 5, $40 for 25.

Safety

• A paid run never starts on its own. The tool answers with the price and your balance first, and the agent has to ask you before calling it again with confirm_spend: true.
• With no credits left, the tool says to top up at stresix.com and starts nothing.
• Each key can start 4 runs an hour, on top of the account's daily limit, so an agent stuck in a loop cannot spend a balance.
• Load only ever goes to the app Stresix builds, on its own server in a private network. It cannot be pointed at a live site.
• A key can start runs and read their status and reports. It cannot buy credits or change the account. Revoke it in Settings and it stops working at once. Only a hash of each key is stored.

Example

You: load test this app before I launch, I'm on a 2 vCPU box

Agent: reads the code, finds the app listens on 3000 and that /, /api/products and /search hit the database, then calls start_load_test with the repo URL

Stresix: Started a Lite run (500 users for 4 minutes against 2 vCPU / 4 GB). This is the free run, nothing was charged.

Agent: polls get_test_status, then calls get_test_report and summarizes what ran out first and what to change.

More at stresix.com/mcp.