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Debugging API Traffic

Inspectr helps you inspect, trace, and debug API requests and responses in real time. Whether you’re working on a backend service or testing an integration, Inspectr gives you the visibility you need.

Step 1: Start Your Backend Service

Section titled “Step 1: Start Your Backend Service”

Ensure your API service is running locally. For example, a backend on port 3000:

Terminal window
npm run dev
# or
python app.py

Step 2: Start Inspectr as a Proxy

Section titled “Step 2: Start Inspectr as a Proxy”

Use the --backend flag to forward requests from Inspectr to your backend:

Terminal window
inspectr --listen=:8080 --backend=http://localhost:3000

  • Inspectr listens on port 8080.

  • Incoming requests will be forwarded to localhost:3000.

  • All requests/responses will be captured and shown in:

  • Console log (color-coded summary)

  • UI App (http://localhost:4004)

Step 3: Send Requests

Section titled “Step 3: Send Requests”

Send requests to your backend through Inspectr:

Terminal window
curl http://localhost:8080/api/users

Or update your frontend/API client to target http://localhost:8080 instead of the original backend.

Step 4: Explore in the UI

Section titled “Step 4: Explore in the UI”

Visit http://localhost:4004 to:

  • Inspect the request method, path, headers, body
  • View the forwarded backend response
  • Filter by status code, method, endpoint
  • Replay past requests for regression testing

Debugging Tips

Section titled “Debugging Tips”

Use Inspectr to debug:

  • 4xx/5xx responses with full request visibility
  • Misconfigured headers or missing tokens
  • Wrong HTTP methods or paths
  • Combine with browser dev tools or API clients (Postman, Insomnia)