What Is an ATOM File?

This article explains what an ATOM file is, how to open one, and how to convert one to a different format.

What Is an ATOM File?

A file with the ATOM file extension is an Atom Syndication Format file saved as a plain text file and formatted like an XML file.

ATOM files are similar to RSS and ATOMSVC files in that they're used by frequently updated websites and blogs to publish content to Atom feed readers. When someone subscribes to an Atom feed through a feed reader tool, they can stay updated on any new content that the site publishes.

Although it's entirely possible to have an .ATOM file on your computer, it's unlikely. Normally, the only time you see ".atom" is when it's appended to the end of a URL that uses the Atom Feed file format. From there, it's less common to save the ATOM file to your computer than it is to simply copy the Atom feed link and paste it into your feed reader program.

How to Open an ATOM File

ATOM files function in much the same way as RSS files, so most feed reader services, programs, and apps that work with RSS files will also work with ATOM files.

FeedDemon is one example of a program that can open Atom feeds. If you're on a Mac, the Safari browser works, too, as does NewsFire.

The RSS Feed Reader Chrome extension from feeder.co can open ATOM files you find on the web and instantly save them to the in-browser feed reader. The same company has a feed reader available here for the Firefox and Yandex browsers, too, and should work the same way.

You can also use a free text editor to open ATOM files, but doing so will only let you read them as a text document to see the XML content. To actually use one as it's intended, you need to open it with one of the ATOM openers above.

You can see how opening an ATOM file in a text editor is doable, but not super useful:

<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
 <title>Lifewire Title</title>
 <subtitle>Subtitle goes here</subtitle>
 <link href="http://example.org/feed/" rel="self" />
 <link href="http://example.org/" />
 <id>urn:uuid:60a76c80-d399-11d9-b91C-0003939e0af6</id>
 <updated>2003-12-13T18:30:02Z</updated>
 <entry>
 <title>What Is an ATOM File?</title>
 <link href="https://www.lifewire.com/atom-file-2619723" />
 <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
        <published>2018-12-09T17:23:02Z</published>
 <updated>2022-12-10T18:30:02Z</updated>
 <summary>This is a plain text format used by web publishers to deliver content to feed readers</summary>
 <content type="xhtml">
 <div xmlns="http://www.w3.org/1999/xhtml">
 <p>This is where the content goes.</p>
 </div>
 </content>
 <author>
 <name>Tim Fisher</name>
 </author>
 </entry>
</feed>

How to Convert an ATOM File

Since the formats are so relatable, you can convert Atom feeds to other feed formats.

Convert ATOM to RSS

For example, to convert Atom to RSS, just paste the Atom feed's URL into this free online Atom to RSS converter to produce an RSS link.

The Atom feed reader extension for Chrome mentioned above can convert an ATOM file to OPML. To do that, load the feed into the program and then use the Export feeds to OPML option from the settings to save the OPML file to your computer.

Convert ATOM to a Spreadsheet Format

If you want the feed content to be displayed in a readable spreadsheet format so you can easily see the title of the article, its URL, and the description, all as reported by the Atom feed, then just convert the Atom feed to CSV.

The easiest way to do that is to use the Atom to RSS converter above and then plug the RSS URL into this RSS to CSV converter.

Convert ATOM to JSON

To convert an ATOM file to JSON, open the .ATOM file in a text editor or in your browser so that you can see the text version of it. Copy all that data and paste it into this RSS/Atom to JSON converter.

How to Embed an Atom Feed

To embed the Atom feed into HTML, use the Atom to RSS converter above and then put that new URL into this RSS to HTML converter. You'll get a script you can embed within HTML to display the feed on your website.

Since an ATOM file is already saved in the XML format, you can use a simple text editor to "convert" it to XML, which will simply change the file extension from .ATOM to .XML. You can also do this manually by just renaming the file extension.