Is my HAR file uploaded anywhere?

No. HAR files often contain cookies, auth headers and request bodies, so this viewer reads the file with the local FileReader API and parses it in your browser — nothing is sent over the network.

What does each column show?

For every request you see the HTTP method, response status, content type (MIME), response size, total time in milliseconds, and the full URL. Status codes 400 and above are highlighted as errors.

Why is a request size shown as a dash?

Some HAR exports record a content size of -1 when the body was not captured (for example cached or blocked responses). Those are shown as a dash and excluded from the total bytes count.

How do I create a HAR file?

Open DevTools (F12) in Chrome, Edge or Firefox, go to the Network tab, reproduce the activity, then right-click any request and choose Save all as HAR with content (or use the download/export icon).

Can I filter the requests?

Yes. Type into the Filter by URL box and the table shows only requests whose URL contains your text — for example api, .js, or a domain name. The request count and total size update to match the filter.

What is a HAR file used for?

HAR (HTTP Archive) files are commonly shared with support teams to diagnose slow pages, failed API calls, and oversized assets. This viewer lets you inspect one yourself before sharing, since they can leak session cookies and tokens.

HAR File Viewer — Gera Tools

View HAR captures privately

A HAR file (HTTP Archive) is a JSON record of the network requests your browser made, exported from the DevTools Network tab. This viewer opens it locally and lays every request out in a table — method, status, type, size and timing — so you can spot slow calls, failed responses and oversized assets without sharing the file with anyone.

How it works

When you select a .har file, the tool reads it with the browser’s FileReader API and parses the JSON. It walks log.entries and, for each request, pulls out the method and URL from request, the status, status text, MIME type and content size from response, and the total round-trip time. Sizes are formatted into B, KB or MB, and a content size of -1 (body not captured) is shown as a dash and left out of the total. You can filter the table by URL substring; the request count and summed byte total recalculate to match what is shown. Status codes of 400 or higher are flagged in red.

Example

Open a HAR captured from a slow page and you might see:

Method	Status	Type	Size	Time	URL
GET	200	text/html	14.2 KB	320 ms	/index.html
GET	200	application/javascript	512.0 KB	1100 ms	/app.bundle.js
GET	404	text/html	-	88 ms	/missing.png

The 512 KB JavaScript bundle taking 1100 ms is the obvious bottleneck, and the 404 highlights a broken asset reference.

Because HAR files frequently include cookies, authorization headers and full request bodies, privacy matters: this tool parses the file entirely in your browser and never uploads it.