HAR Viewer & Analyzer
Find slow, failed and large web requests in an HTTP Archive without uploading the file.
Analyze a HAR file
What a HAR file records
An HTTP Archive stores browser request and response metadata, including URLs, status codes, headers, sizes and timing phases. It helps identify slow origins, failed resources, redirect overhead and unexpectedly large assets.
Understanding HAR timings
Blocked is queueing time; DNS resolves the hostname; connect and SSL establish transport; send writes the request; wait is commonly treated as TTFB; receive transfers the response. Missing phases may be recorded as -1.
Review before sharing
Local processing protects the file from upload, but exported reports can still contain secrets. Remove cookies, authorization headers and sensitive query strings before sharing a HAR with anyone.
Frequently asked questions
Is my HAR file uploaded?
No. The file is read and analyzed entirely in your browser.
Can HAR files contain secrets?
Yes. They may contain cookies, authorization headers, query parameters and form data. Review a HAR carefully before sharing it.
Why can HAR size differ from transfer size?
The HAR JSON includes metadata and may contain embedded response content. Transfer size represents network bytes recorded for requests.
What does wait or TTFB mean?
It is the time between sending the request and receiving the first response byte, including server processing and network latency.