Rich Text Format MIME Type

What does application/rtf mean?

The application/rtf media type identifies a Rich Text Format document. Microsoft designed RTF to exchange formatted text and graphics between word processors, operating environments, and output devices. An RTF file can describe fonts, styles, paragraphs, page layout, tables, fields, footnotes, tracked changes, pictures, and embedded objects while remaining largely text-based.¹

The standard filename extension is .rtf. Every conforming file starts with the five ASCII characters {\rtf, whose hexadecimal bytes are 7B 5C 72 74 66.² The number immediately after that prefix identifies the RTF syntax version used by the file, as in {\rtf1.

Is text/rtf the same as application/rtf?

In practice, both registered media types refer to Rich Text Format. text/rtf was registered in 1993, while the more detailed application/rtf registration was updated in 2007. IANA continues to list both.²³

application/rtf is generally the better label for file transfer. RTF can contain unencoded 8-bit characters and binary picture data, so the IANA registration gives it binary encoding considerations. It also says that RTF defines character encoding inside the document, which makes an external charset parameter redundant.²

The distinction still matters to software. A program may route text/rtf through a text handler and application/rtf through a binary-document handler even when the bytes describe the same format. A filename and a server-provided Content-Type can therefore produce different behavior.

Do not confuse either type with text/richtext. That older MIME format uses angle-bracket commands and is unrelated to Microsoft's backslash-based RTF syntax. The name was confusing enough that the IETF renamed its successor text/enriched.⁴

How is an RTF file structured?

RTF uses braces for groups and backslashes for control words. This is a small complete example:

{\rtf1\ansi\deff0
{\fonttbl{\f0 Arial;}}
\f0\fs24 Plain text, \b bold\b0, and \i italic\i0.\par
}

The outer group begins with \rtf1. \ansi selects a character-set convention, \fonttbl defines available fonts, \fs24 selects 24 half-points, and \par ends a paragraph. Braces let formatting state and destinations nest. A reader that encounters an unknown optional destination can skip its group, which helped newer writers remain usable with older readers.¹

Text encoding is less simple than the file's ASCII-looking surface suggests. RTF has code-page declarations, hexadecimal byte escapes, and Unicode control words with fallback characters for older readers. A naive search-and-replace operation can damage delimiters, change an escape, or modify text that is not part of the visible body.

RTF can also carry pictures and objects. The IANA registration therefore warns that transports limited to textual data may need a binary-safe transfer encoding.² Large hexadecimal image blocks are one reason a real RTF document may be much harder to read as source than the short example above.

Where did RTF come from?

Microsoft published an early RTF description in the March 1987 issue of the Microsoft Systems Journal. RTF 1.0 followed in 1992. Microsoft revised the format alongside successive Word releases, ending with RTF 1.9.1 for Word 2007 in March 2008.⁵

The format's main purpose was interchange. A sender could preserve more structure and presentation than plain text without requiring the receiver to use the same word processor or operating system. Microsoft Word, Apple TextEdit, LibreOffice Writer, and many other applications still open .rtf files. Microsoft documents RTF as a supported Word format, and Apple documents opening, saving, and converting RTF in TextEdit.⁶⁷

RTF is still in use, but its specification has not gained the document features introduced after Word 2007. A modern word processor may therefore lose newer features when saving to RTF. Different applications can also interpret complex tables, fields, drawings, fonts, and embedded objects differently.⁵

How do you open an application/rtf file?

General-purpose web browsers do not provide a native formatted RTF viewer. A browser will normally download the response or hand it to an application selected by the operating system. Use a word processor when layout matters:

• Microsoft Word opens and saves .rtf as a supported document format.⁶
• Apple TextEdit opens RTF, edits formatted text, and exports it to other formats or PDF.⁷
• LibreOffice Writer includes an application/rtf import and export filter.⁸

If you only want to inspect the syntax, use a plain-text or code editor. Check that the file begins with {\rtf; an .rtf suffix alone is not proof of its contents.

Support in Poly

Poly currently has two different paths for this format:

1. The exact application/rtf identifier is recognized as an archive-category type. Poly stores, syncs, shares, versions, and finds the file by name, but it does not parse, render, or index the payload.
2. A filename ending in .rtf is inferred as text/rtf. That type goes through Poly's generic text pipeline, opens in the text editor, and is indexed for full-text and semantic search.

The second path exposes the RTF source, not the formatted document. Searches can match visible words, but they can also match control words, font names, metadata, fallback text, or encoded material. Poly does not remove RTF markup, lay out pages, generate document thumbnails, extract embedded images, or preserve a rendered page model for search.

The same boundary applies to the agent. It can read and edit an .rtf file that Poly classified as text/rtf, but it receives raw RTF syntax. A payload retained as exact application/rtf is not exposed as readable content. For dependable page preview, clean text extraction, and page-aware agent access, convert a trusted RTF to PDF or DOCX and upload the converted copy.

Converting RTF to another format

Choose the output according to what needs to survive:

LibreOffice supports command-line conversion through its documented filters. For example:

soffice --headless --convert-to pdf --outdir converted input.rtf

Conversion is not an extension rename. The application must interpret the RTF control words and write a new representation. When the source is untrusted, perform that interpretation in maintained software with operating-system sandboxing and reasonable resource limits.

Security, privacy, and interoperability

The application/rtf registration says that RTF does not allow executable content and provides no built-in integrity or confidentiality. It also warns about references to external files and objects.² That narrower language-level claim should not be mistaken for a guarantee that every RTF parser is safe.

RTF can contain embedded objects, pictures, fields, links, and large or deeply nested structures. Historically, vulnerabilities in applications that process those features have made malicious RTF attachments a delivery vehicle. Treat an unexpected RTF like any other complex document: keep the viewer updated, avoid enabling external content, and open it in an isolated environment when the sender or origin is uncertain.⁵

Metadata can be easy to overlook. The optional \info group may contain an author, title, company, creation and revision times, comments, and user-defined properties. Tracked changes and annotations can preserve text that is not obvious in the final view.⁵ Inspect document properties and revision content before publishing a sensitive file.

Interoperability depends on the features used, the RTF version a writer emits, the reader's implementation, and the fonts installed on the destination system. For simple styled prose, RTF remains a practical interchange format. For an editable modern document, DOCX or ODT is usually a better working format. For a fixed review or archival copy, use an appropriate PDF profile and retain the original source.