Software & Apps File Types What Is an ATOM File? How to open or convert ATOM files By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated February 18, 2020 File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More Tweet Share Email A file with the ATOM file extension is an Atom Feed 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. ATOM Files. ATOM files have nothing to do with the Atom text editor nor with the telecom acronym AToM, which means Any Transport over MPLS (Multi-Protocol Label Switching). 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. RssReader and FeedDemon are two examples of programs that can open Atom feeds. If you're on a Mac, the Safari browser can open ATOM files, too, as can NewsFire. Some of those programs (FeedDemon being one example) might only be able to open an online Atom feed, like one that you can provide a URL for, meaning that they might not necessarily let you open an .ATOM file you have on your computer. The RSS Feed Reader extension from feeder.co for the Chrome web browser 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, Safari, and Yandex browsers, too, which 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 the ATOM file as it's intended to be used, you need to open it with one of the ATOM openers above. How to Convert an ATOM File Since the formats are so relatable, you can convert Atom feeds to other feed formats. 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 Atom feed into the program and then use the Export feeds to OPML option from the settings to save the OPML file to your computer. 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 own website. Since an ATOM file is already saved in the XML format, you can use a simple text editor to "convert" it to the XML format, which will simply change the file extension from .ATOM to .XML. You can also do this manually by just renaming the file to use the .XML suffix. If you want the feed content to be displayed in a readable spreadsheet format so that 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. 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 of that data and paste it into this RSS/Atom to JSON converter, in the left section. Use the RSS To JSON button to convert it to JSON, and then hit Download to save the JSON file to your computer.