Networking & HTTP·Networking from DNS to production

Debugging requests

Use curl, DevTools and logs to locate the failing layer.

Beginner 14 min read Lesson 7 of 300 Challenge included

What you will be able to do

Use curl -v for headers and connection details.
Use the Network panel for timing and payloads.
Reproduce with the smallest possible request.
Compare working and failing requests.

In plain English

Debugging a request means separating DNS, connection, TLS, request, response and application. curl shows the transport; DevTools shows the browser view; server logs show the application. Find the first layer that is wrong.

terminalTerminal

curl -sS -D - -o /dev/null https://example.com/api/courses
curl -sS -X POST -H 'Content-Type: application/json' -d '{"name":"Ada"}' https://example.com/api/users

Your turn

Send JSON

Easy

Write a curl POST with a JSON body and the correct Content-Type.

BASH · starter

curl -X POST

Check your understanding before moving on.

Knowledge checkQuestion 1

Which curl flag prints response headers?

Select an answer to continue

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Next: REST and status codes

Lesson 7 of 300 · 0% of course