APIsage

Overview

APIsage is an intelligent MCP server designed to help developers analyze, debug, and optimize API endpoints faster.

Instead of manually inspecting responses, APIsage performs end-to-end analysis—covering health checks, failure diagnosis, framework detection, security auditing, performance insights, and test generation.

The flagship analyze-endpoint tool acts as a smart orchestrator. It automatically adapts its workflow: running diagnosis on failures and deeper audits on successful endpoints.

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🔗 Testing Local APIs (Using Cloudflare Tunnel / ngrok)

To test local backend APIs, you need to expose your local server to the internet so APIsage can reach it. You can use any tunneling tool that suits your workflow.

🚀 Recommended: Cloudflare Tunnel

Cloudflare Tunnel is a great primary choice because it provides free, stable HTTPS tunnels without strict session limits.

1. Install cloudflared:

   • Windows: Download from Cloudflare Releases or winget install Cloudflare.cloudflared
   • macOS: brew install cloudflared
   • Linux: sudo apt install cloudflared

2. Start the tunnel:

   cloudflared tunnel --url http://127.0.0.1:8000/
   

   Replace 8000 with your local port.

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⚡ Alternative: ngrok

ngrok is a very popular alternative, though the free tier has some limitations (like mandatory signup and occasional interstitial pages).

1. Start ngrok:

   ngrok http 8000
   

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🛠️ Other Tools

You can use any tool that provides a public HTTPS bridge to your local environment, such as:

• LocalTunnel: npx localtunnel --port 8000
• Tailscale Funnel: For users already in the Tailscale ecosystem.
• Bore / Playit.gg: Great for specific networking needs.

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🔗 Use the URL in APIsage

Once your tunnel is running, copy the Public URL (e.g., https://random-name.trycloudflare.com) and use it in place of localhost:

Before (Local)	After (Public Tunnel)
http://localhost:8000/api/health	https://random-name.trycloudflare.com/api/health
http://127.0.0.1:3000/api/users	https://abc123.ngrok-free.app/api/users

Key Capabilities

• Endpoint Intelligence
  Use check-endpoint to inspect status codes, latency, headers, and response previews instantly.

• Smart Failure Diagnosis
  diagnose-failure identifies root causes (authentication errors, validation issues, server faults) with confidence scores and suggested fixes.

• Framework Detection
  detect-framework infers backend technologies like Express.js, Django, or FastAPI from response patterns.

• Security Audit
  security-audit detects vulnerabilities such as insecure CORS, missing HTTPS, token exposure, and weak authentication.

• Performance Analysis
  performance-analysis evaluates latency and response size, providing optimization insights and performance scoring.

• Auto Documentation
  infer-docs generates API schemas, field descriptions, and example payloads directly from responses.

• Test Case Generation
  generate-test-cases creates ready-to-use curl, Postman, Jest, and Pytest tests with optional live validation.

• Endpoint Comparison
  compare-endpoints highlights schema differences and performance changes between API versions.

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Use Cases

1. Pre-deployment Validation
   Run analyze-endpoint to verify endpoint health, performance, and security before release.

2. Debugging API Failures
   Use diagnose-failure to quickly identify and fix issues in failing endpoints.

3. Automated Testing
   Generate and validate test cases instantly without manual setup.

4. Version Comparison
   Compare endpoints across versions to detect breaking changes and regressions.

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Who This Is For

• Backend developers building and debugging APIs
• Full-stack developers integrating APIs
• Teams needing fast validation, testing, and documentation workflows