Guide
How to Read a HAR File for API Debugging
Use HAR timing, status, host, and content metadata to narrow browser API failures.
Reviewed against the listed primary reference and synthetic local workflow; this is not a runtime or security certification.
Related tools
The debugging problem
A network archive is a timeline, not a verdict. Identify the failing request and its predecessor before assuming the slowest entry caused the incident.
A practical sequence
- Capture a narrow synthetic session.
- Filter failures by status and host.
- Sort by duration and inspect request dependencies.
- Compare Content-Type, cookies, CORS, and response status in context.
Synthetic example
GET /api/orders → 401, 52 ms
OPTIONS /api/orders → 204, 18 ms
GET /assets/app.js → 200, 410 msA failure to watch for
The slow asset is unrelated to the API authorization failure. Timing alone is insufficient without request purpose and response evidence.
Limits and interpretation
HAR may omit details, include cache artifacts, and expose secrets. Redact before sharing; DevPouch never replays URLs.
References
FAQ
What should I verify first when using this how to read a har file for api debugging workflow?
Capture a narrow synthetic session.
What can this workflow not prove?
HAR may omit details, include cache artifacts, and expose secrets. Redact before sharing; DevPouch never replays URLs.