Glossary

What Is a HAR File? How to Create, Read and Share HTTP Archives Safely

Definition: HAR File

A HAR (HTTP Archive) file is a JSON document that records every network request a browser made during a session: URLs, methods, headers, cookies, request and response bodies, status codes and timings. Developers and support teams exchange HAR files to reproduce bugs and diagnose slow pages.

Also called: HTTP Archive, .har, network log export

What is inside a HAR file

A HAR file has one log object containing creator, pages and an entries array. Each entry is one request with its request, response, timings (blocked, dns, connect, ssl, send, wait, receive) and startedDateTime.

Trimmed HAR entry

JSON

1{
2  "startedDateTime": "2026-09-29T10:15:03.120Z",
3  "time": 184.2,
4  "request": { "method": "GET", "url": "https://api.example.com/v1/orders", "headers": [ ... ] },
5  "response": { "status": 200, "content": { "mimeType": "application/json", "text": "{...}" } },
6  "timings": { "dns": 2.1, "connect": 12.4, "ssl": 9.8, "send": 0.3, "wait": 141.0, "receive": 18.6 }
7}

How to export a HAR file

Open Chrome DevTools (F12) and go to the Network panel.
Tick Preserve log, then reproduce the problem.
Use the download icon ("Export HAR") in the Network toolbar.

The ProxyCeptor DevTools panel has its own Network tab with a one-click HAR export, and its Proxy tab keeps a traffic log of which rule acted on each request. See exporting and importing HAR network logs.

HAR files contain secrets: sanitize before sharing

HAR files can include session cookies, Authorization headers, API keys and personal data in bodies. Treat them like credentials. Several real-world breaches started with a HAR file uploaded to a support ticket.

Remove Cookie, Set-Cookie and Authorization headers.
Search for token, key, password and secret in the text.
Prefer the sanitized export option where your browser offers one.
Share the smallest time window that shows the bug.

Frequently asked questions

How do I open a HAR file?

Drag it onto the Chrome DevTools Network panel, or open it in a HAR viewer. It is plain JSON, so any text editor works too.

Can a HAR file be replayed?

Tools can turn HAR entries into mocks. With ProxyCeptor you can turn a captured response into a mock rule and replay it without the real backend.

Why does support ask for a HAR file?

It shows exactly what the browser sent and received, including timing, which is far more precise than a screenshot or a description.

Keep learning

Intercept your first request in under a minute

Create a free ProxyCeptor account to mock, delay, block and rewrite API traffic, then share the same rules with your team.

Create free account Try the live demo ↗