What is the ADR file format?
.adr is a settings file associated with the Opera web browser, used to store user bookmarks. The format is also known as an Opera Hotlist file; its plain-text content begins with the header line Opera Hotlist version 2.0.
ADR files store bookmark entries in an INI-like structure, where each bookmark is represented by a #URL block and each folder by a #FOLDER block, with key-value pairs such as NAME=, URL=, CREATED=, and VISITED=.
ADR files are supported by Opera versions using the Presto engine (Opera 2 through 12.18). Other browsers do not natively recognize this format. ADR data can be imported and exported across user profiles using Opera’s dedicated bookmarks manager and bookmarks wizard tool.
Opera switched from Presto to Chromium/Blink in 2013 (Opera 15), at which point .adr support was dropped in favour of a JSON-based bookmark format. Opera 12.18 (2016) was the last version to support .adr files natively. To migrate bookmarks to a modern browser, open Opera 12.18, import the .adr file, then export as HTML - a format any current browser can import. As plain text, .adr files can also be opened and inspected in any text editor.
Security & safety
RISK: LOWPlain text bookmark list; no executable content. No known security risks.
Format details
in a nutshell- Address Book Data File - Some contact management applications use .adr for vCard-like address book exports.
Programs that open ADR files
Windows2 apps
Opera 12.18
Free Opera menu → Bookmarks → Import and export → Import Opera bookmarks. Select the .adr file.
Any text editor (Notepad++ / VS Code)
Free Open directly - ADR is plain text; read/edit URLs manually. 
macOS1 app
Linux1 app
Technical details
deep spec| File header | First line is "Opera Hotlist version 2.0" - the format identifier |
| Encoding | Plain text (UTF-8; older files may be Latin-1 or Windows-1252) |
| Format structure | INI-like plain text with #URL and #FOLDER block delimiters |
| Bookmark fields | NAME=, URL=, CREATED=, VISITED=, ID= per entry |
| Container | Plain text - no binary container |
| Typical file size | 1 KB - 500 KB (scales with number of bookmarks and folder nesting) |
| Supported Opera versions | Opera 2 through Opera 12.18 (Presto engine, 1996-2016) |
| Successor format | JSON-based bookmarks used by Opera 15+ (Chromium/Blink engine, from 2013) |
| OS compatibility | Windows, macOS, Linux, Unix (wherever Presto-era Opera ran) |
| Migration path | Import in Opera 12 → export as HTML bookmarks → import in any modern browser |
| MIME type | text/plain (no dedicated MIME type registered for .adr) |
| Released | 1996 (Opera 2.x, Presto engine era) |
| Latest version | Opera 12.18 (last Presto-based Opera, 2016) - format no longer produced |
ADR conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about ADR files.
