What is the OPML file format?
.opml is a text file saved in XML format. .opml files store RSS channel information used by RSS readers and aggregators. RSS technology allows users to access news feeds and information about updated or new website content using a single application.
Developed by Dave Winer at UserLand Software and introduced in 2000, OPML became the de facto standard for exporting and importing feed subscription lists between applications such as Feedly and NetNewsWire. Many different OPML versions exist. The most widely used is OPML 2.0; some feeds still use the earlier 1.0 release. An .opml file consists of the following elements:
- version tag,
<head>section - contains file metadata such as title and creation date,<body>section - contains the content of the outline,<outline>elements - carry attributes such astext,type,xmlUrlandhtmlUrl.
Security & safety
RISK: LOWOPML is plain text XML with no executable code, so the file itself is harmless to open. The only caution is that a feed-subscription OPML reveals which sites/feeds you follow (a privacy detail if shared), and that imported feed URLs point to external content - importing a list from an untrusted source just adds those feeds, it doesn't run anything.
Format details
in a nutshellFULL NAMEOutline Processor Markup Languageaka OPML file, Outline file
DEVELOPERUserLand Software (Dave Winer)since 2000 (OPML 1.0); OPML 2.0 in 2007
CATEGORYWeb Files
MIME TYPEtext/x-opml
TYPEXML-based outline/document interchange format (text)
STANDARDOpen · royalty-free
Programs that open OPML files
Windows3 apps
Feedly (web)
Freemium Settings > Import OPML to load your feed subscriptions; the most common reason to 'open' an OPML.
Notepad / Notepad++
Open-source Open the .opml to read or edit the raw XML (it's just text); useful to inspect feed URLs. 
macOS3 apps
NetNewsWire
Open-source File > Import Subscriptions (OPML) to load feeds; modern free successor to the old NetNewsWire. 
Linux1 app
Web2 apps
Opml.org / OPML viewers
Free Reference and tools for the OPML spec; some online viewers render the outline. Technical details
deep spec| File encoding | UTF-8 plain-text XML; no binary magic bytes - files start with `<?xml` and are identified by the `<opml version=` root element |
| MIME type | `text/x-opml`; recognised alternatives include `text/x-opml+xml` and `text/xml` |
| Root element | `<opml>` with a required `version` attribute set to `"1.0"` or `"2.0"` |
| Top-level structure | Two mandatory children of `<opml>`: `<head>` (metadata block) and `<body>` (outline content) |
| Outline hierarchy | Content is built from `<outline>` elements that nest arbitrarily deep to represent multi-level trees |
| Feed subscription attributes | For RSS/Atom feeds each `<outline>` uses `type="rss"`, `text` (label), `xmlUrl` (feed endpoint), `htmlUrl` (website) |
| OPML versions | 1.0 (year 2000) and 2.0 (2007); version declared in the `version` attribute on `<opml>`; 1.1 was an unpublished draft |
| Head metadata fields | Optional fields: `title`, `dateCreated`, `dateModified`, `ownerName`, `ownerEmail`, `expansionState`, `vertScrollState` |
| Compression | None - file is stored as uncompressed plain XML text |
| Typical file size | 1 KB - 500 KB; a typical export of several hundred feed subscriptions is 10-50 KB |
| Primary use | Portable interchange of RSS/Atom feed subscription lists between feed readers and aggregators |
| Secondary use | General-purpose hierarchical outline format for mind-mapping, note-taking and document outlining tools |
| Platform support | Cross-platform: Windows, macOS, Linux, iOS, Android and browser-based web applications |
| Released | 2000 (OPML 1.0); OPML 2.0 in 2007 |
| Latest version | OPML 2.0 (2007) |
| Open standard | Yes · royalty-free |
| Specification | opml.org |
OPML conversions
Possible
.OPML .XMLGUIDE
Yes, and no conversion is actually needed -- OPML is already valid XML, so renaming the file from .opml to…
How to convert
.OPML .HTMLGUIDE
Yes, OPML can be converted to HTML - the most direct route is applying an XSLT stylesheet to the file, which…
How to convert
.OPML .TXTGUIDE
Yes, you can convert OPML to TXT by opening the file in a text editor and copying out the text content, or by…
How to convert
.OPML .CSVGUIDE
Yes -- an online OPML-to-CSV tool is the fastest route; it reads the XML and writes out one feed per row with…
How to convert
Not possible
Community Q&A
asked by usersNo questions yet - be the first to ask about OPML files.
Frequently asked questions
What is an OPML file used for?
Most often to export and import the list of RSS/podcast feeds you subscribe to, so you can move your subscriptions between readers. It's also a generic outline/mind-map exchange format.
How do I open an OPML file?
To just read it, open it in any text editor or browser - it's XML. To actually use it, import it into a feed reader (Feedly, Inoreader, NetNewsWire), podcast app, or an outliner like OmniOutliner.
How do I import OPML into a feed reader?
In Feedly/Inoreader/NetNewsWire look for Settings > Import (OPML) and select the file; the reader adds all the feeds listed inside.
Can I convert OPML to CSV or a spreadsheet?
Yes - an OPML feed list maps to a simple table (title, feed URL). Use an online OPML-to-CSV tool or a short script; there's no built-in OS converter.
Is OPML the same as XML?
OPML is a specific XML dialect - every OPML file is valid XML. You can rename .opml to .xml and open it in any XML tool, but the OPML structure (head/body/outline) is what apps look for.
Why does my OPML file open as code in the browser?
Because it's XML text - the browser shows the raw markup. That's expected; to do something with it, import it into a feed reader or outliner instead of viewing it.
References
1OPML 2.0 specification (opml.org)opml.org
2OPML.org - home of the OPML specopml.org
