Read a HAR without handing it to a stranger.
A .har capture is a full transcript of a browsing session —
every URL, and often your cookies and Authorization headers.
Drop one here to find the slowest requests, the heaviest assets, the
third-party domains and the failures. It is parsed entirely in your
browser; nothing is uploaded.
Drop a .har file
exported from your browser's Network tab — or
.har · stays on your device
— or paste HAR JSON —
Slowest requests
Largest transfers
Third-party domains
Failed requests
FAQ
Is my data sent anywhere?+
No. Your HAR is read and analyzed entirely in your browser — it is never sent to a server. That matters here: a HAR records full request and response details, frequently including cookies, Authorization headers and other secrets, which is exactly why uploading one to a random SaaS is risky. We do count anonymous, aggregate usage on our own server (a page view, that a capture was analyzed) — never your capture, its URLs, or anything inside it.
What is a HAR file and how do I make one?+
A HAR (HTTP Archive) is a JSON log of a browsing session. In Chrome or Edge: open DevTools → Network, reproduce the slow or broken page, then right-click any request → Save all as HAR with content (Firefox and Safari have the same export). Drop that .har here. Because the schema varies a little between browsers, this tool reads only the well-known fields and tolerates the rest being missing.
What does it actually measure?+
It rolls up every entry into totals — request count, bytes over the wire, uncompressed content size and total time — then breaks them down by status code, MIME type and domain. The tables surface the slowest requests (by time), the largest transfers (by _transferSize/bodySize), the third-party domains the page reached for, and the failures (status 0 or 400+). No login, no payment — this one is free.