HAR File Viewer Online
Open a .har file and inspect every request, header, timing, and response in your browser. The capture never leaves your device.
The HAR File Viewer parses your .har entirely in your browser. The requests, cookies, headers, tokens, and response bodies in the capture stay on your device and are never uploaded to ArrayKit.
Open the JSON Viewer
About HAR File Viewer
The HAR File Viewer opens an HTTP Archive (.har) capture and turns it into a readable request list you can inspect in seconds. Drop a file exported from Chrome, Firefox, Edge, or Safari DevTools and every entry shows its method, URL, status, resource type, transfer size, and total time. Expand a row to read request and response headers, query-string parameters, a per-phase timing breakdown (DNS, connect, SSL, wait, receive), and the response body when the capture embedded one. A summary tallies total requests, bytes transferred, wall-clock finish time, and a status-code breakdown so you can spot failures and slow calls at a glance. Because HAR files often contain cookies, auth headers, and tokens, nothing is uploaded — the file is parsed and rendered entirely on your device.
Features
- Drop or open a .har file and see every request as a scannable list
- Per-entry method, URL, status, resource type, transfer size, and total time
- Expand any request to view its request and response headers
- Per-phase timing breakdown: blocked, DNS, connect, SSL, wait, and receive
- Response body preview for entries that embedded the content
- Summary of total requests, bytes transferred, finish time, and status codes
- Filter to only 4xx and 5xx error responses to triage failures fast
- Handles captures from Chrome, Firefox, Edge, and Safari DevTools
How to use the HAR File Viewer
- In your browser DevTools, open the Network panel and export a .har file
- Drop the .har here or click Open .har (or paste the HAR JSON)
- Scan the request list and check the summary for errors and slow calls
- Click a row to inspect its headers, query params, timings, and response
- Use the Errors filter to jump straight to 4xx and 5xx responses
Example
Input
{ "log": { "entries": [ { "request": { "method": "GET", "url": "https://api.example.com/v1/users" }, "response": { "status": 200, "content": { "mimeType": "application/json", "size": 2048 } }, "time": 120 } ] } }
Output
GET 200 api.example.com/v1/users json 2.00 KB 120 ms
One HAR entry rendered as a request row with type, size, and time.
Common errors & troubleshooting
- The file loads but shows 'Not a HAR file'. — Make sure you exported a HAR (an HTTP Archive with a top-level log.entries array), not a plain JSON response or a screenshot. Re-export from the DevTools Network panel.
- Sizes read 0 B for several requests. — Some browsers record bodySize as -1 (unknown) for cached or streamed responses. The viewer falls back to content.size when it can, but a truly missing size stays 0.
- The Response tab says no body was captured. — Response bodies are optional in a HAR. Re-export with 'Include response bodies' or the browser's equivalent option so the content text is embedded.
- Timings look incomplete or every phase is empty. — Phases recorded as -1 are marked 'not applicable' and hidden. Cached, blocked, or preflight entries often omit DNS/connect/SSL, so only the phases that actually ran appear.
Frequently asked questions
- What is a HAR file?
- A HAR (HTTP Archive) file is a JSON log of the network activity a browser recorded for a page. It stores each request and response — method, URL, headers, cookies, timings, and optionally the body — inside a log.entries array, so tools can replay and analyze the session.
- How do I export a HAR from my browser?
- Open DevTools (F12), go to the Network panel, reproduce the activity, then right-click a request and choose 'Save all as HAR' (Chrome/Edge) or use the download/export icon in Firefox and Safari. Load that .har here to inspect it.
- Does the viewer show request and response bodies?
- It shows the response body when the HAR embedded it under content.text; many captures omit bodies to keep the file small. Request headers, query-string parameters, and response headers are always shown when present.
- What do the timing phases mean?
- Each entry breaks its total time into phases: blocked (queueing), DNS lookup, connect (TCP), SSL (TLS handshake), send (upload), wait (server think time / TTFB), and receive (download). Phases the browser did not record are marked not applicable and hidden.
- Can it handle a large HAR with hundreds of requests?
- Yes. The whole file is parsed in your browser and every request becomes a collapsible row, so a large capture stays scrollable. Use the Errors filter to jump straight to failing 4xx and 5xx responses.
- Are the cookies and auth headers in my HAR kept private?
- Yes. HAR files often contain cookies, Authorization headers, and tokens, so the viewer parses and renders the file entirely on your device. Nothing from the capture is uploaded to ArrayKit.
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