How to create and view HAR files for website troubleshooting

Martin Brinkmann
Dec 29, 2020

Most modern web browsers include web development tools that developers and interested users may utilize for a variety of purposes. One of the useful applications that browser makers like Google, Mozilla and Microsoft added to the web development tools of their browsers is the ability to create so-called HAR files.

In this guide, we will explain what HAR files are, how they are created in popular web browsers, and how they can be used by developers to analyze website issues.

What are HAR files?

HAR, which stands for HTTP Archive format, is a log that details a web browser's interaction with a webpage. The log uses the JSON -- JavaScript Object Notation -- format

The HTTP Archive (HAR) format draft, published on August 14, 2012, provides the following definition:

This specification defines an archival format for HTTP transactions that can be used by a web browser to export detailed performance data about web pages it loads.

The document has since been abandoned, but HAR is supported by many modern browsers including Google Chrome, Mozilla Firefox, Internet Explorer and tools such as Fiddler.

The extension of HAR files is .har. The files can be opened in any web browser, specialized viewer applications designed for .har files, any JSON viewer application or extension, and also any text editor.

The purpose of HAR files is to create a record of activity when the browser connects to a site. The file includes information about the resources that are loaded, cookies, downloaded content, and lots of connection details.

What are HAR files used for?

Har files include webpage connection and loading information; one of the main applications is the analysis of site issues, e.g. when a site fails to load correctly in a browser or all browsers.

Web developers may view the output of the HAR file to find potential issues; the files are extremely useful when the developer cannot replicate issues.

Anyone can create a HAR file using web developer tools and send the file to the developer after its creation for analysis.

How to create HAR files

Generally speaking, it is necessary to open the Network Tools of the Developer Tools of the browser that is being used, load the site in question (or part of it depending on the issue), and use a save option to save the recorded data as a HAR file.

Create HAR files in Google Chrome

export har chrome

  1. Use the keyboard shortcut Ctrl-Shift-I to open the Developer Tools, or select Menu > More Tools > Developer Tools.
  2. Switch to the Network tab in the Developer Tools interface.
  3. Load the page or site in question, if it is already open, use the reload button in the interface.
  4. Activate the down arrow icon in the toolbar, it displays Export HAR when you mouse over, to save the HAR file to the local system.

The same method works in most Chromium-based web browsers including Brave, Opera, Vivaldi or Microsoft Edge.

Create HAR files in Mozilla Firefox

export har firefox

  1. Use Ctrl-Shift-E to open the Network tab in Firefox, or use Menu > Web Developer > Network to open it.
  2. Load the webpage or site that you want to create a HAR file for.
  3. Click on the settings icon in the Developer's Tools bar (that looks like a Sun), and select Save all as HAR to export the data.

How to view HAR files

HAR files can be loaded in most browsers that support creating them. You find import HAR file options under Network in those browsers, and may use the imported data to analyze potential site issues.

Other tools exist, such as the online HAR file viewer.

How to create and view HAR files for website troubleshooting
Article Name
How to create and view HAR files for website troubleshooting
The guide offers information on HAR files including what they are, how they are created, and how they can be used using free tools.
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  1. ilev said on August 4, 2012 at 7:53 pm

    Doesn’t Windows 8 know that www. or http:// are passe ?

    1. Martin Brinkmann said on August 4, 2012 at 7:57 pm

      Well it is a bit difficulty to distinguish between domains and files for instance.

    2. Leonidas Burton said on September 4, 2023 at 4:51 am

      I know a service made by google that is similar to Google bookmarks.

  2. VioletMoon said on August 16, 2023 at 5:26 pm

    @Ashwin–Thankful you delighted my comment; who knows how many “gamers” would have disagreed!

  3. Karl said on August 17, 2023 at 10:36 pm


    The comments section under this very article (3 comments) is identical to the comments section found under the following article:

    Not sure what the issue is, but have seen this issue under some other articles recently but did not report it back then.

  4. Anonymous said on August 25, 2023 at 11:44 am

    Omg a badge!!!
    Some tangible reward lmao.

    It sucks that redditors are going to love the fuck out of it too.

  5. Scroogled said on August 25, 2023 at 10:57 pm

    With the cloud, there is no such thing as unlimited storage or privacy. Stop relying on these tech scums. Purchase your own hardware and develop your own solutions.

    1. lollmaoeven said on August 27, 2023 at 6:24 am

      This is a certified reddit cringe moment. Hilarious how the article’s author tries to dress it up like it’s anything more than a png for doing the reddit corporation’s moderation work for free (or for bribes from companies and political groups)

  6. El Duderino said on August 25, 2023 at 11:14 pm

    Almost al unlmited services have a real limit.

    And this comment is written on the dropbox article from August 25, 2023.

  7. John G. said on August 26, 2023 at 1:29 am

    First comment > @ilev said on August 4, 2012 at 7:53 pm

    For the God’s sake, fix the comments soon please! :[

  8. Kalmly said on August 26, 2023 at 4:42 pm

    Yes. Please. Fix the comments.

  9. Kim Schmidt said on September 3, 2023 at 3:42 pm

    With Google Chrome, it’s only been 1,500 for some time now.

    Anyone who wants to force me in such a way into buying something that I can get elsewhere for free will certainly never see a single dime from my side. I don’t even know how stupid their marketing department is to impose these limits on users instead of offering a valuable product to the paying faction. But they don’t. Even if you pay, you get something that is also available for free elsewhere.

    The algorithm has also become less and less savvy in terms of e.g. English/German translations. It used to be that the bot could sort of sense what you were trying to say and put it into different colloquialisms, which was even fun because it was like, “I know what you’re trying to say here, how about…” Now it’s in parts too stupid to translate the simplest sentences correctly, and the suggestions it makes are at times as moronic as those made by Google Translations.

    If this is a deep-learning AI that learns from users’ translations and the phrases they choose most often – which, by the way, is a valuable, moneys worthwhile contribution of every free user to this project: They invest their time and texts, thereby providing the necessary data for the AI to do the thing as nicely as they brag about it in the first place – alas, the more unprofessional users discovered the translator, the worse the language of this deep-learning bot has become, the greater the aggregate of linguistically illiterate users has become, and the worse the language of this deep-learning bot has become, as it now learns the drivel of every Tom, Dick and Harry out there, which is why I now get their Mickey Mouse language as suggestions: the inane language of people who can barely spell the alphabet, it seems.

    And as a thank you for our time and effort in helping them and their AI learn, they’ve lowered the limit from what was once 5,000 to now 1,500…? A big “fuck off” from here for that! Not a brass farthing from me for this attitude and behaviour, not in a hundred years.

  10. Anonymous said on September 28, 2023 at 8:19 am

    When will you put an end to the mess in the comments?

  11. RIP said on September 28, 2023 at 9:36 am

    Ghacks comments have been broken for too long. What article did you see this comment on? Reply below. If we get to 20 different articles we should all stop using the site in protest.

    I posted this on [] so please reply if you see it on a different article.

    1. RIP said on September 28, 2023 at 11:01 am

      Comment redirected me to [] which seems to be the ‘real’ article it is attached to

  12. RIP said on September 28, 2023 at 10:48 am

    Comment redirected me to [] which seems to be the ‘real’ article it is attached to

  13. Mystique said on September 28, 2023 at 12:13 pm

    Article Title: Reddit enforces user activity tracking on site to push advertising revenue
    Article URL:

    No surprises here. This is just the beginning really. I cannot see a valid reason as to why anyone would continue to use the platform anymore when there are enough alternatives fill that void.

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