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OPML File Format (.opml)

An OPML file is an XML document made of nested outline elements, most often used to move a list of RSS and Atom feed subscriptions from one feed reader to another.

.opmlDocuments

OPML at a glance#

Full nameOutline Processor Markup Language
File extension.opml
CategoryDocuments
DeveloperUserLand Software
MIME typestext/x-opmltext/xmlapplication/xml
CompressionUncompressed
SpecificationOPML 2.0
FileFlip supportFileFlip reads and writes this format

What a .opml file can hold#

These are the things a OPML file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.

Embedded metadataYes
Selectable textYes
Human readableYes
Schema or validationYes

Strengths and limitations of OPML#

What OPML does well

  • Every feed reader that supports subscription export and import agrees on the same OPML structure
  • Nested outline elements can represent folders of feeds, not just a flat list
  • Plain XML, so a file can be inspected or edited by hand without special software

Where OPML falls short

  • Carries no styling or formatting, only the outline structure itself
  • Outside RSS subscription lists, general-purpose outliner use of OPML has mostly faded
  • Different feed readers store slightly different attributes on each outline element, so a round trip between two apps can drop details neither one recognizes

Use OPML to move a list of feed subscriptions between RSS readers, or to export a hierarchical outline from an outliner app.

Convert OPML into a document format like HTML or Markdown when the outline itself, not the feed subscriptions, needs to be read as a document.

How to open a .opml file#

A .opml file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts OPML into a format your machine already opens, and it does it in the browser tab rather than on a server.

PlatformPrograms that open it
WindowsNetNewsWire, Feedly, Inoreader
macOSNetNewsWire, Feedly
WebFeedly, Inoreader, FileFlip

OPML questions people ask#

What is an OPML file?

An OPML file is an XML document that stores a nested outline, most commonly a list of RSS and Atom feed subscriptions. Feed readers use it to export a subscription list from one app and import it into another.

What do I use an OPML file for?

The main use of an OPML file today is moving feed subscriptions between RSS readers like Feedly, Inoreader or NetNewsWire, so switching apps does not mean resubscribing to every feed by hand. UserLand Software originally designed OPML for general hierarchical outlines, not just feeds.

Can I edit an OPML file by hand?

Yes, an OPML file is plain XML text, so it opens and edits in any text editor. Each subscription or outline entry appears as an outline element with attributes like a title and, for feeds, the feed's URL.

Converting OPML files#

Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.