api-testing-mcp — Claude Code MCP server: what it does, how to install
MCP server for API testing through conversation. HTTP requests with assertions, multi-step flows, OpenAPI import, load testing, and response comparison.
claude mcp add api-testing-mcp -- npx -y @cocaxcode/api-testing-mcpWhat api-testing-mcp does
The server provides tools for HTTP requests (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS) with headers, query params, body, Bearer/API Key/Basic auth, and variable interpolation. You can set assertions on status and body, chain requests with data extraction, import an OpenAPI spec and generate schema-aware requests, run load tests with percentile metrics, compare responses between environments, build test collections, and run them as a suite. Environments, groups, and collections are stored as local JSON.
Response compression (since version 0.13) cuts context size by 70–95 %: the verbosity parameter with values minimal, normal, and full controls detail level, only_fields returns only specified body paths, max_body_bytes truncates the body. For loops or health checks, minimal saves 95 % of tokens. Full responses can be retrieved later by call_id. Requires Node.js 20 or later.
What it helps with
- send an HTTP request with status and body assertions
- run a multi-step flow extracting tokens between calls
- import an OpenAPI spec and generate requests from the schema
- run a load test and get response time percentiles
- compare the same endpoint between two environments
Example prompts for the agent
- Create a dev environment with BASE_URL
http://localhost:3000 - Import my API spec from
/api-docs-json - GET
/usersand verify status is 200
How to install api-testing-mcp
Platform CLI
claude mcp add api-testing-mcp -- npx -y @cocaxcode/api-testing-mcpPlatform CLI
codex mcp add api-testing-mcp -- npx -y @cocaxcode/api-testing-mcpConfig file
{
"mcpServers": {
"api-testing-mcp": {
"command": "npx",
"args": [
"-y",
"@cocaxcode/api-testing-mcp"
]
}
}
}Config file
{
"servers": {
"api-testing-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@cocaxcode/api-testing-mcp"
]
}
}
}Platform CLI
gemini mcp add api-testing-mcp npx -y @cocaxcode/api-testing-mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about api-testing-mcp
How to install api-testing-mcp in Claude Code?
Run claude mcp add api-testing-mcp -- npx -y @cocaxcode/api-testing-mcp. For Cursor or Windsurf, add an entry to .cursor/mcp.json or .windsurf/mcp.json with command npx and args ["-y", "@cocaxcode/api-testing-mcp"].
What does api-testing-mcp do?
It provides tools for HTTP requests with assertions, multi-step flows with variables, OpenAPI spec import, load testing, response comparison between environments, and running test collections. All through conversation, no file generation.
What does response compression do in api-testing-mcp?
The verbosity parameter with values minimal, normal, and full reduces response size in the agent context by 70–95 %. Minimal mode keeps only status, timing, and first 200 body characters, useful for health checks and loops. Full responses can be retrieved later by call_id.
