Paste the contents of a browser network export (.har) to see the slowest requests, any failures, and a content-type breakdown. Nothing is ever uploaded.
Slowest requests
URL
Status
Time (ms)
Failed requests (4xx/5xx)
URL
Status
No failed requests — everything returned under 400.
Content type breakdown
Type
Requests
Total size
How it works
The pasted HAR's log.entries array is scanned locally: each entry's transferred size (falling back from content.size to bodySize when needed) is grouped by MIME type for the breakdown, entries are sorted by their time field for the slowest-10 list, and any entry with a response status of 400 or above is listed as failed.
FAQ
Why does it fall back to bodySize instead of content.size for some requests?
Because some HAR exports report content.size as -1 or 0 when the response body's real decoded size wasn't captured, such as for cached or compressed responses — bodySize is the size actually transferred, so it's used whenever content.size isn't a usable positive number.
Does the 4xx/5xx count include requests blocked by an ad blocker or CORS?
Only if the browser's network panel actually recorded an HTTP response with that status — a request blocked before any response, or one that failed due to CORS with no status, won't show up as a numeric status at all and is skipped by this check.
Free, unlimited, no account. If this saved you a paid tool, a small thanks is appreciated.