OPML vs RST
A detailed comparison of OPML Outline and reStructuredText — file size, quality, compatibility, and which format to choose for your workflow.
OPML Outline
Documents & TextOPML (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.
About OPML filesreStructuredText
Documents & TextRST (reStructuredText) is a lightweight markup language used in Python documentation.
About RST filesStrengths Comparison
OPML 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.
RST Strengths
- Rich directives for admonitions, code, math, and custom elements.
- Cross-references work within and across documents.
- Sphinx ecosystem offers best-in-class Python docs output.
- Standardized as part of Python PEP infrastructure.
- Plain text, version-controllable.
Limitations
OPML 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.
RST Limitations
- Syntax denser than Markdown — higher learning curve.
- Less widely adopted than Markdown outside Python world.
- Multiple directive dialects (Sphinx, Docutils, custom) create fragmentation.
- MyST (Markdown + Sphinx) has pulled many Python projects toward Markdown.
Technical Specifications
| Specification | OPML | RST |
|---|---|---|
| MIME type | text/x-opml | text/x-rst |
| Extension | .opml | .rst |
| Format | XML with nested <outline> elements | — |
| Standard | OPML 2.0 (2006) | — |
| Primary use | RSS subscription interchange | — |
| Toolchain | — | Docutils, Sphinx, Read the Docs |
| Encoding | — | UTF-8 |
| Related formats | — | MyST (Markdown + RST directives) |
Typical File Sizes
OPML
- Typical RSS reader export (50 feeds) 5-30 KB
- Deep outline (Scrivener novel plan) 20-200 KB
RST
- API reference page 5-50 KB
- Sphinx project chapter 20-100 KB
- Full library documentation 500 KB - 10 MB
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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.
OPML (OPML Outline) is a document formato used to store paginated text, com optional formatoting, tables, images, hyperlinks, headers e footers. It sits no documents & text family e is tipicamente associated com a specific office suite ou publishing pipeline that defined the formato e 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.
Modern office suites — Microsoft Word, Google Docs, LibreOffice Writer, Apple Pages — abrir most OPML arquivos com reasonable fidelity. If your installed software does not support OPML, converter to DOCX ou PDF first usando KaijuConverter; both abrir in virtually every reader, including grátis 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.