What Is a HAR File?
A HAR file, short for HTTP Archive, is a JSON-based record of network activity captured while a website or web application is loading and communicating with servers. A HAR can contain request URLs, HTTP methods, response status codes, headers, timing information, cookies, query parameters and other diagnostic details depending on how the capture was created.
This HAR file viewer converts the raw archive into a simpler request list so you can quickly scan methods, status codes, URLs and request duration without manually reading the JSON structure.
How to Use This HAR File Viewer
Select a .har file or compatible JSON export using the file picker above. The viewer parses the archive locally in your browser, counts the detected requests, summarizes successful 2xx responses and HTTP errors, and calculates the sum of the recorded request durations.
Each request row shows the HTTP method, response status, URL and recorded request time. Click a row to inspect the serialized HAR entry for that request. The detailed entry can contain additional request and response information provided by the original archive.
Find failed network requests
HTTP 4xx and 5xx responses are common starting points when debugging a web application. A 404 can indicate a missing resource or incorrect path, while a 500-series response often points to a server-side failure. The summary above counts responses with status codes of 400 or higher so errors are easier to identify.
Investigate slow requests
HAR files are useful when a site or application feels slow but the source of the delay is unclear. Comparing request durations can help you spot API calls, scripts, images, fonts or third-party resources that took unusually long to complete. The displayed total time in this viewer adds individual request durations; because browser requests can overlap, that total is not the same thing as page-load wall-clock time.
Inspect API and third-party traffic
A HAR request list can make it easier to see which hosts and endpoints a page contacted. Developers and support teams can use that information to review API calls, redirects, third-party services, analytics requests or resources loaded from external domains.
How to Export a HAR File
Modern browsers provide HAR export from their developer tools. In Chrome and Microsoft Edge, open Developer Tools, choose the Network panel, reproduce the problem or reload the page, and use the HAR export option. Firefox also provides HAR export from its Network tools. Browser labels and menus can change over time, so use the network panel's export or save-HAR control available in your browser version.
When troubleshooting an intermittent issue, start the network capture before reproducing the problem so the relevant requests are included in the archive.
HAR File Privacy and Security
HAR files can contain sensitive diagnostic information. Depending on the capture, that may include cookies, Authorization headers, bearer tokens, API keys, query parameters, form values, request bodies, email addresses, internal hostnames, account identifiers or session tokens. Treat HAR exports like sensitive support files.
This viewer reads the selected file locally using browser JavaScript and does not upload the HAR to a Utiliverse server. The redaction helper masks common credential-like fields in the on-screen detail view and can create a sanitized HAR copy for review before sharing.
What the sanitizer checks
- Request and response headers commonly used for authentication or session state.
- HAR cookie arrays and
Cookie/Set-Cookieheader values. - Query-string and form parameter names that look like tokens, keys, passwords, secrets or session identifiers.
- JSON request bodies and readable JSON response bodies where sensitive-looking object keys can be identified.
- Matching sensitive query parameters embedded directly in request URLs.
The sanitizer deliberately does not delete entire requests or rewrite arbitrary free-form text because doing so could destroy useful debugging context. When a body cannot be parsed safely, the viewer leaves it intact and relies on the warning above so you can review it manually.
How This Viewer Interprets a HAR
The viewer expects a JSON object containing log.entries. It does not attempt to repair malformed captures or reconstruct data that was not exported. Each table row is based on one HAR entry's request method, response status, URL and recorded time value.
What redaction now covers
The sanitizer masks common sensitive request and response headers, cookie-array values, matching query/form parameters, sensitive query parameters embedded in request and redirect URLs, and recognizable sensitive keys in JSON request bodies. It also attempts the same key-based redaction for JSON response bodies when the response content is stored as readable JSON text.
What redaction still does not guarantee
Arbitrary free-form text, HTML, XML, binary data, base64 payloads, unexpected parameter names, email addresses, internal hostnames, account numbers, or secrets embedded inside opaque strings may remain unchanged. The helper also does not know which business-specific fields your organization considers confidential.
Large captures and browser memory
The viewer parses the entire HAR into browser memory, creates deep copies during redaction, and serializes a complete second copy when downloading a sanitized file. Very large captures can therefore be slow or exceed the memory available to a browser tab, especially on mobile devices.
Original file integrity
The original selected file is never rewritten by this page. Filtering, detail redaction and sanitization operate on in-memory copies. Download Sanitized HAR creates a separate file, preserving the original capture for private troubleshooting or comparison.
Worked examples
Status summary:
200 → counted as 2xx
302 → not counted as 2xx or error
404 → counted as error
0 → not counted as an HTTP error
Timing example:
Request A: 900 ms
Request B: 700 ms
Displayed total: 1,600 ms
If the two requests overlapped, actual elapsed time can be much less than 1,600 ms.
Common HAR Troubleshooting Uses
- Find 4xx and 5xx responses during a bug investigation.
- Identify unusually slow requests or API calls.
- Review request methods, URLs and external hosts.
- Investigate redirects and missing resources.
- Inspect an exported network capture from a user or QA report.
- Compare request behavior before and after a deployment or configuration change.
HAR viewer vs. browser DevTools
Browser DevTools remains the richer environment for live network debugging because it can provide filters, initiator information, waterfall timing, live captures and other diagnostics. A standalone HAR analyzer is useful when you already have an exported archive and want a quick browser-based view without recreating the original session.
Redaction workflow before sharing a HAR
A practical workflow is: reproduce the issue, export the HAR, open it locally here, keep the redaction option enabled while inspecting entries, download a sanitized copy, then manually review that sanitized file before sharing it. If the support recipient does not need request bodies or certain private endpoints, consider removing those requests entirely in a dedicated text editor or capture a narrower session.
Last reviewed: October 1, 2026 · Viewer behavior, privacy guidance and redaction logic reviewed against the current implementation.
HAR File Viewer FAQ
What does HAR stand for?
HAR stands for HTTP Archive. It is a JSON-based format used to record HTTP network requests and responses from a browser or other compatible debugging tool.
Can I open a .har file here?
Yes. Select a HAR file or compatible JSON export using the file picker above.
Does my HAR file leave my computer?
The parsing in this page runs locally in your browser and does not upload the selected HAR file to a Utiliverse server.
Can I inspect individual requests?
Yes. Click a request row to view the serialized details stored for that HAR entry.
Can HAR files contain cookies or authentication tokens?
Yes. HAR files may contain cookies, authorization headers, URLs, query parameters, request bodies and other sensitive data. Review and sanitize a HAR before sharing it.
What do 4xx and 5xx responses mean?
4xx responses generally indicate a client or request problem, while 5xx responses generally indicate that the server could not complete the request.
Does total request time equal page load time?
Not necessarily. This viewer adds recorded request durations. Multiple browser requests can overlap, so the sum can be longer than the actual elapsed page-load time.
Can this replace browser DevTools?
No. It is a lightweight viewer for exported HAR files, not a replacement for the full live Network panel in browser developer tools.
What does the HAR redaction helper remove?
It masks common sensitive headers, cookies, query parameters, form fields and JSON keys such as authorization values, API keys, tokens, passwords, secrets and session identifiers. It is heuristic and may not catch every sensitive value.
Is a sanitized HAR automatically safe to share?
No. Always review the sanitized file manually. Secrets can appear under unexpected field names, inside opaque request bodies or in URLs and data that no generic sanitizer can identify reliably.
Does the viewer change my original HAR file?
No. The original file stays unchanged. The Download Sanitized HAR button creates a separate copy in your browser.
Does the sanitizer inspect response bodies?
When a response body is stored as readable JSON text, the sanitizer attempts to mask values under sensitive-looking keys. Arbitrary text, HTML, XML, binary or opaque response content is not generically sanitized.
Why is status 0 not counted as an HTTP error?
Status 0 is not a server-issued HTTP status code. It can appear when a request is incomplete, blocked, cancelled, unavailable to the capture, or represented differently by the exporting tool.
Can a very large HAR file fail to open?
Yes. The viewer loads the full archive into browser memory and may create additional copies for redaction and sanitized download, so very large captures can exceed available memory.