What is the OBI file format?
.obi is an XML-based format introduced in Microsoft Outlook 2007 for sharing and exporting RSS feed subscriptions. When a user chose "Share This Feed" or exported subscriptions from Outlook, the application produced an .obi file - typically named <profilename>.sharing.xml.obi and stored in %LOCALAPPDATA%\Microsoft\Outlook\.
The file is a plain XML document containing OPML-style outline elements, each describing one subscribed feed: its title, xmlUrl (the feed endpoint), htmlUrl, and Outlook-specific metadata fields. No encryption or compression is applied, and the file is human-readable in any text editor.
The .obi format is inseparable from a feature that no longer exists. Outlook 2007, 2010, and 2013 included a built-in RSS reader, but Microsoft removed native RSS support in Outlook 2016 and from Microsoft 365 entirely. Sending an .obi file to a recipient running a modern Outlook version has no practical effect because the import mechanism was removed.
For portable RSS subscription exchange today, the standard alternative is OPML (.opml), supported by virtually all modern feed readers. The .obi content can be recovered by opening the file as XML and extracting the feed URLs listed in each xmlUrl attribute.
Security & safety
RISK: LOWOBI files are plain XML containing only RSS feed URLs; no code execution, no macros. Safe to open in a text editor. The only risk is a malicious URL embedded as a feed URL - check before subscribing to unknown feeds.
Format details
in a nutshell- Kerio Connect / older mail clients - Some mail server/client products adopted the .obi extension for Outlook-exported sharing files.
Programs that open OBI files
Windows2 apps
Microsoft Outlook 2007/2010/2013
Paid Account Settings → RSS Feeds → Import; or double-click the .obi file if Outlook 2007-2013 is default handler. Technical details
deep spec| Encoding | UTF-8 text (declared in XML header) |
| Format | XML document - no binary sections |
| File naming convention | <profilename>.sharing.xml.obi |
| Default storage path | %LOCALAPPDATA%\Microsoft\Outlook\ (Windows) |
| XML structure | OPML-style outline elements, one per subscribed RSS feed |
| Per-feed attributes | title, xmlUrl (feed endpoint), htmlUrl, Outlook-specific metadata |
| Typical file size | 1 KB - 50 KB (grows with number of subscriptions) |
| Compatible Outlook versions | Outlook 2007, 2010, 2013 (RSS feature removed in Outlook 2016 and Microsoft 365) |
| MIME type | application/xml |
| Modern equivalent | OPML (.opml) - universal, reader-agnostic feed subscription exchange format |
| Feature status | Deprecated - native RSS reader removed from Outlook 2016 and Microsoft 365 |
| Released | 2006 (Microsoft Outlook 2007) |
| Latest version | Outlook 2010 era; format unchanged since |
| Specification | support.microsoft.com |
OBI conversions
Community Q&A
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