About OPML Files
OPML Outline
OPML (Outline Processor Markup Language) is an XML format for structured outlines and lists. It is most widely used for exchanging RSS feed subscription lists between podcast apps and feed readers, and for hierarchical note-taking.
Family
Documents & Text
Extension
.opml
MIME Type
text/x-opml
Can Use As
4F 50 4D 4C 00 01 00 00 4B 41 49 4A
ASCII: OPML....KAIJ
📈 Target Minimum File Size (Guaranteed ≥ KB)
Lossless JPEG Q100 + standard COM segment padding for government & exam portals
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HOW OPML CAME TO BE.
OPML — Outline Processor Markup Language — was created by Dave Winer at UserLand Software in 2000 as an XML format for storing hierarchical outlines. Winer was one of the early blogging pioneers, and OPML became the de-facto format for sharing lists of RSS feed subscriptions between feed readers. Every RSS client (NetNewsWire, Google Reader, Feedly, Inoreader) imports and exports OPML files; this is the standard way to migrate your RSS subscriptions from one reader to another.
OPML’s use broadened beyond RSS into outline editors, mind-mapping tools (Scrivener, OmniOutliner), and lesson-planning software. The format is intentionally simple — nested `<outline>` elements with arbitrary attributes — which makes it both easy to implement and endlessly extensible. OPML’s continued existence, 25 years after Google Reader’s death, is proof that standards designed for portability outlive the tools that created them.
Technical Specifications
- MIME type
- text/x-opml
- Extension
- .opml
- Format
- XML with nested <outline> elements
- Standard
- OPML 2.0 (2006)
- Primary use
- RSS subscription interchange
Typical Sizes & Weights
Typical RSS reader export (50 feeds)
5-30 KB
Deep outline (Scrivener novel plan)
20-200 KB
STRENGTHS & LIMITATIONS.
Strengths
- Standard RSS subscription interchange format.
- Simple XML — easy to parse and generate.
- Highly extensible via arbitrary attributes.
- Supported by every major outline and RSS tool.
Limitations
- XML verbosity — larger than a JSON-based equivalent.
- Specification is loose — different tools disagree on edge cases.
- Primary use (RSS reading) has shrunk dramatically since Google Reader.
- No strong central stewardship.
CURIOSITIES & TRIVIA.
Every RSS reader — NetNewsWire, Feedly, Inoreader, Miniflux — imports and exports OPML as the standard subscription-list format.
Google Reader's 2013 shutdown sent millions of users scrambling to export their subscriptions as OPML before the deadline.
Dave Winer also co-authored the RSS 0.92 and 2.0 specs — the same blogging pioneer who shaped the RSS ecosystem created its migration format.
OmniOutliner, Scrivener, and Workflowy all support OPML import — outlines are portable across the writing-app landscape.
OPML is XML with exactly one required element: nested `<outline text="..."/>`. That simplicity is why it's lasted 25 years.
Specialized Utilities for .OPML Files
Merge PDF
Combine multiple PDF files into a single document. Drag and drop to reorder pages before merging. No software installation required.
Split PDF
Split a PDF into separate files by page ranges or extract individual pages. Perfect for isolating chapters, invoices, or specific sections.
Compress PDF
Reduce PDF file size without visible quality loss. Choose from low, medium, or high compression levels. Ideal for email attachments and web uploads.
PDF to Word Converter
Convert PDF documents into editable Microsoft Word (DOCX) files online for free while preserving layout, tables, and typography.
Word to PDF Converter
Convert Microsoft Word documents (DOCX, DOC) into print-ready PDF files with exact font embedding and layout preservation.
PDF to Excel Converter
Extract tables, financial rows, and structured columns from PDF files directly into editable Microsoft Excel (XLSX) spreadsheets.
Make PDF Searchable (OCR)
Add a searchable text layer to scanned PDF documents using OCR. The visual appearance stays the same but you can now search, select, and copy text.
Unlock PDF
Remove owner printing/copying restrictions and decrypt password-protected PDF files instantaneously once you enter the known password.
CONVERT FROM OPML
Common Use Cases
RSS feed subscription exchange, podcast directories, outline/mindmap tools
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Popular OPML conversions
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Frequently Asked Questions
OPML (OPML Outline) is a document format used to store paginated text, with optional formatting, tables, images, hyperlinks, headers and footers. It sits in the documents & text family and is typically associated with a specific office suite or publishing pipeline that defined the format and ships the canonical reader.
Modern office suites — Microsoft Word, Google Docs, LibreOffice Writer, Apple Pages — open most OPML files with reasonable fidelity. If your installed software does not support OPML, convert to DOCX or PDF first using KaijuConverter; both open in virtually every reader, including free online viewers.
Upload the OPML to KaijuConverter and pick DOCX, PDF, ODT, RTF, HTML, Markdown, or plain text. Our pipeline runs LibreOffice headlessly plus pandoc for text formats — the same engines behind professional document pipelines. Styles, tables, images, and hyperlinks survive the conversion intact.
Yes, to a high degree. Standard fonts, headings, lists, tables, images, hyperlinks and page structure transfer cleanly. Custom fonts substitute to the closest match if not embedded; obscure layout features unique to OPML (frames, legacy macros) may flatten to static content in the target format.
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