The Network panel shows what the browser sends and receives. Use it to investigate missing data, failed actions, slow pages and caching problems.

On this guide
CaptureInspectReplayConnection testsHAR files

Capture requests

  1. Open DevTools before reproducing the issue.
  2. Open Network and clear the list.
  3. Enable Preserve log if the page will navigate.
  4. Enable Disable cache when you need fresh resources.
  5. Reproduce one clear flow.
  6. Filter by Fetch/XHR, JS, CSS, Img, WS or part of the URL.

Inspect a request

AreaCheck
HeadersURL, method, status, query, request and response headers.
PayloadForm data, JSON body and uploaded values.
Preview / ResponseReturned data and safe error details.
TimingQueueing, connection, server wait and download time.
InitiatorScript, document or action that triggered the call.
CookiesCookies sent, received or blocked.
Waterfall tip: long waiting time can point to the server. Long queueing or many blocking resources may point to browser-side loading.

Replay and edit

  • Right-click and choose Replay XHR to resend a request.
  • Use Edit and Resend where available to change URL, headers or body.
  • Choose Copy as cURL to reproduce the request outside the browser.
  • Compare successful and failing calls.

Before replaying a write request, check that it will not create duplicate orders, emails or payments.

Connection tests

Throttling

Select a slow network profile and verify loading, progress and timeout behaviour.

Offline

Switch to Offline, perform an action, then reconnect and check recovery.

Block requests

Block an image, script, API or third-party service and verify graceful failure.

Cache

Compare first load, cached load and disabled-cache behaviour.

HAR files

A HAR file contains a captured request timeline. Right-click the request table to export it, and import it later for analysis.

  • Reproduce only the relevant flow before export.
  • Check the file for tokens, cookies, personal data and request bodies.
  • Sanitise sensitive values before sharing.
  • Add time, environment and reproduction steps to the ticket.

Useful links