Free browser tool
HAR Analyzer
Analyze request counts, transfer size, timing, domains and HTTP errors from a HAR file.
Private: your HAR file is processed locally and is not uploaded.
When to use the HAR Analyzer
Use it to find what makes a page slow or broken: export a HAR file from the browser's network panel and see the heaviest, slowest and failing requests.
Examples
- Spot a 2 MB unoptimised image that dominates page weight.
- Find third-party scripts returning 4xx or 5xx errors.
Common mistakes
- Sharing a HAR file publicly; it can contain cookies and auth tokens.
- Recording with the cache enabled and missing first-visit costs.