A HAR file is a record of everything your browser downloaded to load a webpage

HAR stands for HTTP Archive. When you visit a website, your browser makes dozens of requests — for the HTML page itself, images, stylesheets, scripts, fonts, and other files. A HAR file captures all of those requests and responses in a single text file that you can open and read.

Think of it like a receipt that shows every item your browser fetched, how long each one took to arrive, and whether it succeeded or failed. Web developers and support staff use HAR files to troubleshoot slow pages, broken images, or features that won't load. The file contains technical details but no passwords or personal data you typed into forms.

You do not create HAR files by default — your browser does not save them automatically. You have to export one manually from your browser's developer tools when you need to diagnose a problem or share loading details with someone helping you.

Key Takeaways

  • A HAR file records every file your browser downloaded when loading a webpage, including images, scripts, and stylesheets, along with timing and success or failure information.
  • HAR files are plain text and can be opened in any text editor, though the content is technical and meant for developers or support staff to read.
  • You export a HAR file from your browser's developer tools — the process takes under a minute and works the same way in Chrome, Firefox, Safari, and Edge.
  • A HAR file does not contain passwords, credit card numbers, or text you typed into forms, but it does show which websites you visited during the recording.
  • Support staff sometimes ask you to send a HAR file when a website is slow or broken, because it shows exactly where the delay or failure happened.

How to export a HAR file from your browser

The steps are nearly identical across Chrome, Firefox, Safari, and Edge. Open the webpage that is having a problem, then open your browser's developer tools by pressing F12 (or Ctrl+Shift+I on Windows, Cmd+Option+I on Mac). Click the Network tab at the top of the developer tools panel.

Reload the webpage by pressing F5 or Ctrl+R. Watch the Network tab fill with requests as the page loads. Once the page has fully loaded and you see no new requests appearing, right-click anywhere in the Network tab and select Save all as HAR with content (the exact wording varies slightly by browser, but the option will include the word "HAR"). Choose where to save the file on your computer — your Downloads folder is fine. The file will have a name like archive.har.

If you are troubleshooting a problem that happens after the page loads — like a button that does not work or content that loads slowly later — keep the Network tab open and perform the action that is broken. Then save the HAR file. This captures the requests that happened during the problem, which is what the person helping you needs to see.

What information is inside a HAR file

A HAR file is formatted as JSON, which is a structured text format. If you open it in Notepad or any text editor, you will see entries for each request your browser made. Each entry includes the URL that was requested, the HTTP method (usually GET), the response status (200 means success, 404 means not found), how many bytes were downloaded, and how long it took.

The file also records response headers — technical information the server sent back — and request headers, which include things like your browser type and the website you came from. This is why support staff can see which page you were on when the problem occurred.

HAR files do not contain passwords, credit card numbers, or any text you typed into login forms or search boxes. They also do not contain the actual content of images or videos, only the requests for them. However, the file does show which websites you visited during the time the Network tab was recording, so do not share a HAR file if you are concerned about privacy during that window.

When to send a HAR file to support staff

If a website is running slowly, a support person might ask you to send a HAR file so they can see where the delay is happening. Maybe images are taking too long to download, or a script from a third-party service is blocking the page. The HAR file shows the exact timing for each request, which narrows down the problem in seconds instead of hours of guessing.

Similarly, if a feature is broken — a button does not respond, a form will not submit, or content will not load — a HAR file can show whether the browser even tried to fetch that content, whether the server rejected the request, or whether something else went wrong. This is especially useful when the problem only happens for you and not for everyone, because the HAR file proves what your browser actually did.

Before you send a HAR file to anyone, open it in a text editor and scan it quickly. Look for any URLs or data that concern you. If you see something sensitive, you can delete those lines before sending, though most support staff will ask you not to edit the file because incomplete data makes it harder to diagnose the problem.

HAR files and bookmarking or saving content

A HAR file is not a way to save or bookmark a webpage for later reading. It is a technical log, not a copy of the page itself. If you want to save a webpage to read offline or to bookmark it, use your browser's built-in bookmark feature or a dedicated bookmarking tool — those are designed for that purpose and will actually preserve the content you want to see.

HAR files are created for troubleshooting only. Once you have solved the problem or sent the file to support staff, you can delete it. There is no reason to keep HAR files around unless you are a developer who needs to compare loading performance over time.

Opening and reading a HAR file yourself

You can open a HAR file in any text editor — Notepad, Word, or any other program that reads plain text. The content will be readable but dense and technical. Each request is listed with dozens of properties, and unless you are familiar with HTTP and web performance, most of it will not mean much to you.

If you want to view a HAR file in a more readable format, several free online HAR viewers exist. You can search for "HAR file viewer" and upload your file to one of these tools. They display the same information in a cleaner layout with charts and summaries. Do not upload a HAR file to a viewer if you are concerned about privacy — use an offline viewer or a viewer that clearly states it does not store uploaded files.

Frequently Asked Questions

Does a HAR file contain my passwords or credit card information?

No. HAR files do not capture text you typed into forms, including passwords, credit card numbers, or search queries. They record only the requests your browser made and the server's responses. However, the file does show which websites you visited, so consider privacy before sharing one.

Can I use a HAR file to save a webpage offline?

No. A HAR file is a technical log of requests and responses, not a copy of the webpage itself. To save a webpage for offline reading, use your browser's "Save page as" feature or a bookmarking tool designed for that purpose.

Why does the support person want a HAR file instead of just a screenshot?

A screenshot shows what you see, but a HAR file shows what your browser actually did behind the scenes. It reveals whether files downloaded successfully, how long each one took, and whether the server rejected any requests. This information is invisible in a screenshot but essential for diagnosing the real problem.

What if I accidentally delete the HAR file after I save it?

You can create a new one anytime by repeating the steps: open developer tools, go to the Network tab, reload the page, and save as HAR. There is no limit to how many HAR files you can export, so do not worry about losing one.

Is it safe to share a HAR file with someone I do not know?

A HAR file does not contain passwords or payment information, but it does show which websites you visited during recording. Only share a HAR file with official support staff from the website having the problem, or with someone you trust. If you are unsure, ask what specific information they need before sending the file.