Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.OPML
File Type
Outline Processor Markup Language
Category
Data
Best first step
Use compatible software
Quick Summary
A practical overview of the .opml file format
Outline Processor Markup Language (OPML) is an XML-based file format designed for the exchange of outline-structured information between applications. Originally developed by UserLand Software, it has become the industry standard for managing lists of RSS feeds, podcast subscriptions, and hierarchi…
File extension
.OPML
File type
Outline Processor Markup Language
Category
Data
Recommended action
Open with a trusted compatible app
How to open a .opml file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .opml.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .opml file?
File extension details and usage information
Outline Processor Markup Language (OPML) is an XML-based file format designed for the exchange of outline-structured information between applications. Originally developed by UserLand Software, it has become the industry standard for managing lists of RSS feeds, podcast subscriptions, and hierarchical data structures. Because it is built on XML, it is platform-independent and human-readable, allowing users to export their entire subscription list from one news aggregator or podcast client and import it into another seamlessly. Beyond feed management, OPML is frequently used by outliner software to store structured notes, brainstorming hierarchies, and project task lists. Its tree-based structure allows for nested elements, making it highly efficient for representing complex, multi-level information architectures in a lightweight, portable format that is easily parsed by web services and desktop applications alike.
Software Compatibility
Programs that may open or work with .opml files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .opml files be converted?
Options for saving or exporting this file to another format
In many cases, a .opml file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .opml file.
Why can't I open a .opml file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .opml format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .opml files
To open a .opml file, use software that supports this file format.
- FeedDemon
- Notepad++
- RSS Bandit
- NetNewsWire
- OmniOutliner
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .opml file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.