HAR Viewer Online — Open, Filter & Inspect HTTP Archive Files
Free HAR viewer online: open .har files, filter 2xx/4xx/5xx requests, search URLs, and inspect headers and bodies in your browser. Learn how to export HAR from Chrome, Firefox, and Safari.
Read a HAR file without DevTools.
Got a .har from a customer or a failing CI run? Spoold's HAR Viewer lists every request with method, status, URL, time, and size, with filters for 2xx, 3xx, 4xx, and 5xx — all parsed locally.
What is a HAR file?
HAR (HTTP Archive) is a JSON format, currently version 1.2, that records what a browser did on the network: a log.entries array where each entry has a request, response, timings, and optionally the response body.
How to export a HAR
What you can do in the viewer
Filter by status
One click on 4xx or 5xx shows the failing calls; counts on each chip show how many there are.
Search URLs
Type part of an API path to isolate one endpoint across hundreds of requests.
Inspect details
Request and response headers, query strings, cookies, and body previews (large bodies are truncated).
Timing breakdown
See blocked, DNS, connect, TLS, wait, and receive phases to tell network from backend delay.
How to use it on Spoold
- Open /tools/web/har-viewer.
- Drop a .har file, or choose Paste JSON and click Parse HAR.
- Use the status chips and URL search to narrow the list.
- Click a request to open headers, bodies, and timings.
HARs contain secrets
Captures often include cookies, bearer tokens, and personal data. The viewer never uploads the file, and history keeps only a compact request list. Still, sanitize a HAR before sending it to anyone else.
Debugging tips
- Look up unfamiliar codes in HTTP Status Codes.
- Replay a call with the HTTP Request tool.
- Missing bodies usually mean the export did not include content, or the browser did not retain it.
Related search terms
Frequently asked questions
Is the HAR viewer free?
Can I paste HAR JSON instead of uploading?
Why are response bodies missing?
How large a HAR can I open?
What does history store?
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