MIME (Multipurpose Internet Mail Extensions) types are short strings that identify file formats: 'text/html', 'image/png', 'application/json'. Originally designed for email attachments (1991), they became the standard way for HTTP servers to tell browsers what kind of file they're serving. The Content-Type header on every HTTP response is a MIME type.

What's the format of a MIME type string?

type/subtype, optionally with parameters: 'text/html', 'image/png', 'application/json; charset=utf-8'. The 'type' is a broad category (text, image, audio, video, application, font, message, model, multipart). The 'subtype' specifies the format. The optional parameters add details (charset for text, boundary for multipart). 'application/vnd.example' types are vendor-specific extensions.

Why does the server's MIME type matter to my browser?

The browser uses Content-Type to decide what to do with the response: render as HTML, display as image, play as video, prompt to download, or execute as JavaScript. Wrong MIME type breaks rendering, a JS file served as 'text/plain' won't execute as a script; an image served as 'application/octet-stream' downloads instead of displaying. For static files, the server matches file extensions to MIME types via a config table.

What is 'application/octet-stream'?

The generic 'unknown binary data' MIME type. Servers fall back to this when they don't recognize a file extension. Browsers handle it by downloading (since they don't know how to render arbitrary bytes). It's also useful for forcing a download, set Content-Type to application/octet-stream and the browser will prompt to save, even for files it could render.

What's the difference between text/javascript and application/javascript?

Historically, both were used for JavaScript files. RFC 4329 (2006) deprecated 'text/javascript' in favor of 'application/javascript'. Then HTML5 (2014) reverted and standardized 'text/javascript' as the canonical type. Both still work in all browsers; 'text/javascript' is now the official modern recommendation. Same story with text/css vs application/css, text/css is canonical.

What are the most important MIME types to know?

text/html (web pages), text/css (stylesheets), text/javascript (JS), application/json (APIs), application/pdf (PDFs), image/png + image/jpeg + image/webp + image/svg+xml (web images), application/x-www-form-urlencoded (form submissions), multipart/form-data (file uploads), application/octet-stream (generic binary). These cover ~95% of web traffic.

Is this reference list always up to date?

It covers the IANA-registered types plus common de-facto types (image/webp, image/avif, etc.). New types are added to IANA periodically. For an authoritative current list, check iana.org/assignments/media-types. The reference here is curated for common web/dev usage rather than exhaustive.

What standards does MIME Type Reference validate against?

MIME Type Reference checks compliance with RFC 6838 (Media Types), IANA Media Types Registry.

What are the limitations of MIME Type Reference?

Does not check file content, extension-based only Does not cover all vendor-specific MIME types

📄

MIME Type Reference

100% Local

Searchable reference of 60+ MIME types with file extensions and categories.

MIME Type Reference

Extension(s)MIME TypeCopy

.html.htm

text/html

HTML document

.css

text/css

Cascading Style Sheets

.js.mjs

text/javascript

JavaScript

.txt

text/plain

Plain text

.csv

text/csv

Comma-Separated Values

.xml

text/xml

XML document

.md

text/markdown

Markdown document

.ics

text/calendar

iCalendar format

.json

application/json

JSON data

.jsonld

application/ld+json

JSON-LD linked data

.pdf

application/pdf

PDF document

.zip

application/zip

ZIP archive

.gz

application/gzip

Gzip compressed

.tar

application/x-tar

TAR archive

.7z

application/x-7z-compressed

7-Zip archive

.rar

application/vnd.rar

RAR archive

.wasm

application/wasm

WebAssembly binary

.swf

application/x-shockwave-flash

Adobe Flash

.bin

application/octet-stream

Binary data

.yaml.yml

application/yaml

YAML document

.toml

application/toml

TOML document

.sql

application/sql

SQL file

.rtf

application/rtf

Rich Text Format

.xls

application/vnd.ms-excel

Excel spreadsheet

.xlsx

application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

Excel Open XML spreadsheet

.doc

application/msword

MS Word document

.docx

application/vnd.openxmlformats-officedocument.wordprocessingml.document

Word Open XML document

.ppt

application/vnd.ms-powerpoint

PowerPoint presentation

.pptx

application/vnd.openxmlformats-officedocument.presentationml.presentation

PowerPoint Open XML

.png

image/png

PNG image

.jpg.jpeg

image/jpeg

JPEG image

.gif

image/gif

GIF image

.webp

image/webp

WebP image

.svg.svgz

image/svg+xml

SVG vector image

.ico

image/x-icon

Icon image

.avif

image/avif

AVIF image

.bmp

image/bmp

Bitmap image

.tiff.tif

image/tiff

TIFF image

.heic

image/heic

HEIC image (Apple)

.mp3

audio/mpeg

MP3 audio

.wav

audio/wav

WAV audio

.ogg.oga

audio/ogg

OGG audio

.flac

audio/flac

FLAC lossless audio

.aac

audio/aac

AAC audio

.webm

audio/webm

WebM audio

.m4a

audio/mp4

MP4 audio

.mp4.m4v

video/mp4

MP4 video

.webm

video/webm

WebM video

.ogg.ogv

video/ogg

OGG video

.avi

video/x-msvideo

AVI video

.mov.qt

video/quicktime

QuickTime video

.mkv

video/x-matroska

Matroska video

.ts

video/mp2t

MPEG transport stream

.ttf

font/ttf

TrueType font

.otf

font/otf

OpenType font

.woff

font/woff

Web Open Font Format

.woff2

font/woff2

Web Open Font Format 2

.eot

application/vnd.ms-fontobject

Embedded OpenType font

58 of 58 MIME types shown

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Search by file extension or MIME type. Results show the full type name, category, and common usage.

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Overview

What is MIME Type Reference?

Searchable reference of 60+ MIME types by category (Text, Application, Image, Audio, Video, Font) with file extensions and one-click copy of any MIME string.

FAQ

Frequently Asked Questions

Reference

Technical Deep Dive

DEVELOPMENT TOOLS

MIME Type Reference

A complete searchable and filterable reference of 60+ MIME types organized by category (Text, Application, Image, Audio, Video, Font). Each entry shows file extensions, MIME type string, and description. Filter by category or search by extension or MIME type. Copy any MIME type with one click.

⚙

Built for Devs

🧠

Smart Defaults

Reasonable assumptions out of the box, every assumption overridable when you need it.

🚀

Workflow-Friendly

Pairs with your IDE, CI, and code review, output drops into commits and PRs cleanly.

01 Major Media Category Matrix

Type Category	Canonical Example	Primary Use Case
`text/`	`text/html`	Markup and scripts
`application/`	`application/json`	Structured data / Binary
`image/`	`image/webp`	Raster/Vector visuals
`font/`	`font/woff2`	Web typography
`multipart/`	`multipart/form-data`	File upload streams

02 Content Negotiation Workflow

Acceptance Declaration The client specifies preferred formats via the Accept header (e.g., Accept: application/json).

Resource Mapping The server identifies the file extension or resource type and selects the corresponding IANA-registered MIME type.

Type Reification The Content-Type header is injected into the response, instructing the browser's rendering engine on how to parse the byte stream.

03 Real-World Use Cases

MIME types matter most when they're wrong. These are the security and UX scenarios where the right Content-Type is load-bearing.

⬇️

Content-Type for downloads Returning application/octet-stream with Content-Disposition: attachment; filename="..." forces a "Save As" dialog instead of inline render. The right combination is the difference between "downloads my report.csv" and "opens an unreadable wall of text in a new tab."
🛡

X-Content-Type-Options: nosniff Without nosniff, browsers may sniff content and render an attacker-uploaded "image" as HTML, classic XSS vector. Set X-Content-Type-Options: nosniff alongside an honest Content-Type, always.
📤

Uploaded-file validation Never trust the MIME type the client claims in multipart/form-data, anyone can put image/jpeg on a .php file. Read the magic bytes server-side, then re-derive the type.
❓

application/octet-stream as last resort RFC 6838 calls this the "generic binary" type. Servers fall back to it when extension lookup fails. It's safe, browsers refuse to execute it as a script, but UX-hostile (no preview, always downloads).
📨

Vendor-tree types (application/vnd.*) IANA registers vendor-prefixed types per RFC 6838 §3.2, Office docs (application/vnd.openxmlformats-officedocument.spreadsheetml.sheet) and proprietary formats live here. They're the long, ugly ones; they're also the canonical ones.

04 Worked Examples

EXAMPLE 1 · image/jpeg IS CANONICAL, image/jpg IS WRONG

IANA registry entry:

image/jpeg ← registered (RFC 2046, RFC 3745)

image/jpg ← NOT registered, but tolerated by every browser

Why this matters:

Browsers: accept both (Chrome, Firefox, Safari, Edge)
Strict validators (JSON-Schema "image/*" allowlists,
   email gateways, S3 ContentType policies):
   may reject "image/jpg" as unknown.
Always emit "image/jpeg".

The .jpg file extension is fine and ubiquitous, it's only the MIME string that has a canonical form. RFC 3745 also covers image/jp2 (JPEG 2000), often confused with this pair.

EXAMPLE 2 · text/csv vs application/csv vs application/vnd.ms-excel

Three MIME types for the same .csv file:

text/csv                  → IANA-registered (RFC 7111)
                            renders inline if browser can
application/csv           → unregistered, widely tolerated
                            tends to trigger download
application/vnd.ms-excel  → Excel claims it
                            opens directly in Excel on Windows

UX outcome by Content-Type returned:

"export.csv" with text/csv                → may render in browser
"export.csv" with application/csv         → reliably downloads
"export.csv" with application/vnd.ms-excel → opens in Excel
                                            (Outlook attachments do this)

Pair with Content-Disposition: attachment if you always want a download. text/csv is the spec-correct choice; the others are pragmatic UX hacks.

EXAMPLE 3 · MAGIC-BYTE DETECTION (DON'T TRUST CLIENT MIME)

First bytes of common formats (hex):

PNG:  89 50 4E 47 0D 0A 1A 0A
JPEG: FF D8 FF                  (then E0/E1/DB for variant)
GIF:  47 49 46 38 39 61         ("GIF89a")
PDF:  25 50 44 46 2D            ("%PDF-")
ZIP:  50 4B 03 04                ("PK")
WebP: 52 49 46 46 ?? ?? ?? ?? 57 45 42 50  ("RIFF....WEBP")

Server-side validation pattern:

const head = await readBytes(file, 0, 12);
if (head.slice(0,8).equals(Buffer.from([0x89,0x50,0x4E,0x47,
                                       0x0D,0x0A,0x1A,0x0A])))
  type = "image/png";
// ...
// NEVER: type = req.file.mimetype  (attacker-controlled)

The file(1) Unix command uses the same magic-byte database. Libraries like file-type (npm) and python-magic wrap this for you. Always re-derive type server-side before storing or serving.

05 Related Tools

Content-Type lives next to other HTTP semantics, status codes, header inspection, and the CORS preflight that the browser fires when a request's Content-Type triggers it.

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HTTP Header Checker

Verify Content-Type, Content-Disposition, X-Content-Type-Options as a server actually sends them, not what you think you configured.

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HTTP Methods Reference

A Content-Type beyond application/x-www-form-urlencoded, multipart/form-data, or text/plain triggers a CORS preflight, methods and types are entangled.

🌐

CORS Checker

Diagnose preflight failures caused by a "non-simple" Content-Type on a cross-origin fetch, most common cause of mysterious browser 0-status errors.

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RJRahul JalavadiyaFounder & Lead Engineer

Last reviewed 2026-07-29

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What is MIME Type Reference?

Frequently Asked Questions

What is a MIME type?

What's the format of a MIME type string?

Why does the server's MIME type matter to my browser?

What is 'application/octet-stream'?

What's the difference between text/javascript and application/javascript?

What are the most important MIME types to know?

Is this reference list always up to date?

Technical Deep Dive

Built for Devs

Smart Defaults

Workflow-Friendly

01 Major Media Category Matrix

02 Content Negotiation Workflow

03 Real-World Use Cases

04 Worked Examples

05 Related Tools

HTTP Header Checker

HTTP Methods Reference

CORS Checker

Runs 100% in your browser

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Git Commit Message Generator

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AI Code Review Assistant

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