Endpoint Discovery
Automatically discover API endpoints from an OpenAPI spec, Swagger file, or by crawling a base URL. Returns a structured list of routes, methods, and parameters.
MCP Server · npm package
AI-Powered API Testing & Documentation
An MCP server that gives AI agents 9 tools to test, validate, and document your APIs. Endpoint discovery, request generation, response validation, contract testing, and OpenAPI generation — all callable programmatically.
$25/mo. No usage limits. Cancel anytime.
The Problem
APIs break silently in production
Most teams test APIs manually with Postman collections that go stale, or they skip testing altogether and rely on users to find regressions. API documentation is even worse — written once at launch, outdated within weeks, never trusted again.
40%
Of production outages are caused by undetected API contract breakages during deploys
8 hrs
Average time to write a comprehensive Postman test suite for a 20-endpoint API
3×
Developer productivity lift when working from accurate, up-to-date API documentation
The Solution
9 MCP tools for AI-driven API testing
TRUSS API Testing MCP lets AI agents test any REST API programmatically. From endpoint discovery to contract validation and OpenAPI generation — agents handle the entire testing lifecycle.
Request Generation
Generate valid and edge-case HTTP request payloads for any endpoint based on schema definitions. Includes boundary values, null fields, and type mismatches.
Response Validation
Check HTTP responses against expected schemas, status codes, and headers. Flag missing fields, type mismatches, and unexpected response shapes.
Contract Testing
Verify that your API conforms to its OpenAPI contract. Detects breaking changes: removed fields, changed types, new required parameters, altered status codes.
Authentication Testing
Test API authentication flows: Bearer tokens, API keys, OAuth2, and cookie-based auth. Verify that protected endpoints reject unauthorized requests correctly.
Load Testing
Send concurrent requests to measure throughput, latency percentiles (p50/p95/p99), and error rates under load. Identify bottlenecks before they hit production.
OpenAPI Generation
Observe your API endpoints and auto-generate a complete OpenAPI 3.0 specification. Ready for Swagger UI, Postman import, or any API documentation portal.
API Version Diffing
Compare two versions of an API or OpenAPI spec and produce a structured diff of breaking vs non-breaking changes. Use in CI to block breaking deploys.
API Mocking
Generate a mock server from an OpenAPI spec that returns valid example responses. Lets frontend teams build against APIs before the backend is ready.
How It Works
From install to tested API in 60 seconds
TRUSS API Testing MCP is a standard MCP server. Install via npm, add to your agent config, and start testing any REST API immediately.
-
01
Install and configure
Install via npx. Add your target API's base URL and optional OpenAPI spec location to the MCP environment config.
-
02
Add to your MCP client
Add to Claude Code, Cursor, or any MCP-compatible client. The 9 API testing tools are available immediately in your agent's tool list.
-
03
Let your agent test the API
Ask your agent to "discover and test all API endpoints" or "check for breaking changes in this deploy." The agent calls the MCP tools, builds a test suite, and reports issues with exact request/response details.
# Claude Code / Cursor MCP config
{
"mcpServers": {
"api-testing": {
"command": "npx",
"args": ["truss-api-mcp"],
"env": {
"API_BASE_URL": "https://api.yourservice.com",
"OPENAPI_SPEC_URL": "https://api.yourservice.com/openapi.json",
"TRUSS_API_KEY": "your-api-key"
}
}
}
}
Pricing
Simple, flat pricing
One plan. Unlimited API testing. $25/mo flat.
Pro
$25/mo
Unlimited API testing for one developer or CI environment.
- All 9 MCP tools
- Any REST API
- OpenAPI 3.0 support
- Contract testing
- API version diffing
- Load testing
- API mock generation
- Works with Claude Code & Cursor
Tool Reference
All 9 API testing tools
- 01 discover_endpoints — Auto-discover API routes from OpenAPI spec or base URL crawl
- 02 generate_requests — Generate valid and edge-case request payloads for any endpoint
- 03 validate_response — Check responses against expected schema, status codes, and headers
- 04 run_contract_tests — Verify API conforms to its OpenAPI contract, detect breaking changes
- 05 test_auth — Test authentication flows and verify access control is enforced
- 06 run_load_test — Measure throughput, latency percentiles, and error rates under load
- 07 generate_openapi — Auto-generate OpenAPI 3.0 spec from observed API behavior
- 08 diff_api_versions — Diff two API specs and classify breaking vs non-breaking changes
- 09 mock_api — Spin up a mock server returning valid example responses from spec
FAQ
Frequently asked questions
What APIs can the API Testing MCP server test?
Any REST API — public or private, local dev server or production. Provide a base URL and optional OpenAPI spec. The agent uses discover_endpoints to map all available routes before testing.
How does AI API testing differ from Postman or manual testing?
Postman requires you to manually build and maintain test collections. With MCP, your AI agent actively reasons about what to test, generates edge cases you'd miss manually, and can update its test suite based on API changes automatically.
Can it generate OpenAPI documentation automatically?
Yes. The generate_openapi tool observes your API, infers request/response schemas, and produces a standards-compliant OpenAPI 3.0 specification ready for Swagger UI, Postman, or any API portal.
Does it work with Claude Code and Cursor?
Yes. TRUSS API Testing MCP is a standard MCP server. Add it to your mcpServers config in Claude Code, Cursor, or any MCP-compatible client and the 9 tools appear immediately.
Stop writing Postman collections by hand
Give your AI agents the tools to discover, test, and document any API automatically. Install in 60 seconds.
Get API Testing MCP — $25/moFlat $25/mo. No usage limits. Cancel anytime.