MIME Type Lookup

How to use

1. In the "Search by extension, MIME type, or word" field, type the extension you want to look up (.jpg), a MIME type (application/json), or the name of a format (font)
2. The list below narrows to the entries that match. Each one shows its MIME type, the name of the format, its extensions, other spellings, and anything to watch for
3. Choose a kind such as image under "Kind" to see only the types of that kind

There is no button to press. The list changes as you type. The page opens with every type listed in alphabetical order.

Checking a file by its content

Choose a file under "Check a file by its content", or drop one on that box, and the mark of its format at the start of the file (its magic number) is read. The result lists:

• From the content — the type the mark shows. When the file can be served as more than one type, as an animated PNG can (image/apng and image/png), all of them are listed
• Mark found — the name of the mark and the bytes found at which position. For ZIP and MP4 it also says which entry or brand decided the type
• From the extension — the type the list gives for the extension of the file name
• Type from the browser — the type the browser gave the file when you chose it. An older spelling comes with the type from the list
• Content-Type to serve — the type both agree on, or the content's type when they disagree. A text type gets a charset when the encoding is known
• First 16 bytes — the first 16 bytes of the file in hexadecimal

Above them comes a verdict such as "The content matches the extension" or "The extension does not match the content". "Show this type in the list" shows the type to serve in the list below.

Only the parts used to tell the format, such as the start and the end of the file, are read, up to 64 KB each, and the file is never uploaded. The content cannot tell:

• Text formats — CSV, JSON, Markdown, and others have no fixed mark. When the content is text, the extension's type is used. HTML, SVG, XML, RTF, shell scripts, WebVTT, iCalendar, vCard, and HLS playlists are guessed from how they start. A file that starts with an XML declaration and whose first element is not <svg is taken as application/xml; whether it is RSS, Atom, or another XML format is not checked
• Word, Excel, and PowerPoint 97–2003 — they share a container (a Compound File), so the list of streams inside is read to tell them apart. When the list cannot be read in full, and for a password-protected .docx, .xlsx, or .pptx (which goes in the same container), the format is left open
• Formats not in the list, and formats with no mark — a format this check does not know, such as an .eot font, gives "The content does not show the format"

Ways to search

• Extension — with a leading ., as in .png, only extensions are searched, from their first character. .woff finds both .woff and .woff2
• File name — type photo.jpg or archive.tar.gz and the last extension is used
• MIME type — a whole type such as application/json works, and so does a part such as svg+xml or vnd.ms-excel. font/ finds every type that starts with font
• Header value — paste text/html; charset=utf-8 or Content-Type: application/json with its parameters or header name, and only the type is searched
• Other spellings — an older or unregistered spelling such as application/javascript or image/x-icon finds the current type
• Name of the format — search by a word from the name or the note, such as subtitles, Excel, or font
• Several words — words separated by spaces must all match. excel 2003 finds application/vnd.ms-excel

Without the dot, js also finds entries that have js in the type or the name, such as application/json. text/javascript, whose extension is exactly js, comes first. Case is ignored, and full-width characters (．ｐｎｇ) are read the same way.

Example

Type .jpg and the list narrows to one entry.

image/jpeg
JPEG image — Extensions: .jpg .jpeg

Type .woff and two entries appear.

font/woff     WOFF font — Extensions: .woff
font/woff2    WOFF2 font — Extensions: .woff2

Type application/javascript and the current type, text/javascript, appears, with application/javascript under "Also written".

Type .ts and you get video/mp2t (MPEG transport stream) and text/tab-separated-values (.tsv). The note explains why a TypeScript file is treated as video.

Rename a PNG image to photo.jpg and choose it under "Check a file by its content", and the result reads:

The extension does not match the content — photo.jpg (20,512 bytes)
From the content         image/png — PNG image
Mark found               PNG signature — at the start: 89 50 4E 47 0D 0A 1A 0A
From the extension       .jpg → image/jpeg — JPEG image
Type from the browser    image/jpeg
Content-Type to serve    image/png

The browser's type comes from the extension; the content is still a PNG. Choose a Word .docx file and it is found to be a Word document from the ZIP signature and the word/document.xml inside.

What a MIME type is

A MIME type names the format of some data in a short string such as image/png. Its formal name is "media type". A web server writes it in the Content-Type header of a response to tell the browser what the body is.

Content-Type: text/html; charset=utf-8

A browser decides what to do from this header, not from the extension in the URL. Even when a URL ends in .html, a Content-Type of text/plain makes the browser show the HTML source as plain text.

How it is written

The part before the / is the broad category (the top-level type) and the part after it is the specific format (the subtype).

• text — text a person can read. text/html, text/css, text/csv
• image — images. image/png, image/jpeg, image/svg+xml
• audio — audio. audio/mpeg, audio/ogg
• video — video. video/mp4, video/webm
• font — fonts. font/woff2, font/ttf
• application — data and documents that fit no other category. application/json, application/pdf, application/zip
• multipart — several parts in one body. multipart/form-data

Subtypes follow a few conventions.

• +json, +xml, +zip — the format underneath. image/svg+xml is an image written in XML, and application/ld+json is data written in JSON
• vnd. — a format that belongs to a company or product. application/vnd.ms-excel is Microsoft Excel
• x- — the mark once used for unregistered types. Some, such as application/x-tar, are still in wide use

Parameters can follow a ;. For text types, charset=utf-8 gives the character encoding.

Types that are easy to get wrong

JavaScript is text/javascript

application/javascript used to be the official type. RFC 9239 in 2022 made text/javascript official and obsoleted application/javascript. Browsers run either, but use text/javascript in new configuration. .mjs has the same type.

A file loaded with <script type="module"> does not run unless it is served with a JavaScript type. Serving it as text/plain or application/octet-stream produces an error in the console.

.jpg is image/jpeg

There is no image/jpg. The type is image/jpeg whether the extension is .jpg or .jpeg. In the same way, .svg is image/svg+xml and not image/svg, .ico is image/vnd.microsoft.icon (often written image/x-icon), and .mp3 is audio/mpeg and not audio/mp3.

.ts is not TypeScript

The .ts extension belongs to a video format, the MPEG transport stream (video/mp2t). TypeScript source has no registered type. What a browser receives is the compiled JavaScript, so this rarely matters.

CSS and nosniff

When a response carries X-Content-Type-Options: nosniff, a browser refuses a stylesheet served with any type other than text/css and a script served with any type other than a JavaScript one. When styles do not apply, check Content-Type in the Network tab of the developer tools.

Form submissions

An HTML form sent with POST has a body of application/x-www-form-urlencoded by default. The enctype attribute decides the format. To send files, the form must set enctype="multipart/form-data" so that the body is multipart/form-data. Without it, only the names of the files are sent. To send JSON to an API, set application/json yourself.

Which types are listed

The list holds the types that come up most in web development. It is not every type. The full set of registered types is in the "Media Types" registry of IANA (the body that manages internet numbers and names), which has more than 2,000 entries.

Types not registered with IANA

A type marked "Not registered with IANA" was not in the IANA registry as of October 12, 2026. There are twelve.

• application/rss+xml, application/vnd.android.package-archive
• application/x-7z-compressed, application/x-bzip2, application/x-sh, application/x-tar
• audio/midi, audio/wav, audio/webm
• text/event-stream
• video/webm, video/x-msvideo

They work even so, because browsers and servers support them widely. Browsers play video/webm and audio/wav, and the HTML Standard defines text/event-stream. Registration says whether a type is on the official list, not whether it can be used.

Other spellings

"Also written" lists older types for the same format, and unregistered ones that are in use anyway, such as application/x-zip-compressed (what browsers on Windows send for a ZIP file) and image/x-icon. Use the heading type when you configure something yourself, and accept the other spellings as well when you build the receiving side.

To look up what the status code of a response means, use the HTTP Status Code Lookup.

FAQ

What is a MIME type?

A string such as text/html or image/png that names the format of some data. It began as a way for email to say what an attachment is (MIME: Multipurpose Internet Mail Extensions) and is now used by HTTP as well. Its formal name is "media type".

Is Content-Type different from a MIME type?

Content-Type is the name of a header in HTTP and email, and a MIME type is the string written as its value. In Content-Type: application/json, Content-Type is the header and application/json is the MIME type.

What happens when the extension and the MIME type disagree?

The browser follows Content-Type. An image that downloads instead of displaying, CSS that does not apply, and a script that does not run can all come from a wrong type. A server chooses Content-Type from a table that maps extensions to types, such as mime.types in nginx.

Which type should I use for an extension that is not listed?

When the format is unknown or has no type of its own, use application/octet-stream. A browser usually saves a URL of this type as a file instead of displaying it when it is opened directly. To make sure of a download, add a Content-Disposition: attachment header. For the format of a particular product, check that product's documentation or the IANA registry.

Is it all right to use a type that starts with x-?

Where no registered type exists and the x- type is the de facto standard, as with application/x-tar, use it as it is. The habit of adding x- to new types was dropped by RFC 6648 in 2012. Where a registered type exists, such as application/gzip, use that one.

Can I trust the type of an uploaded file?

No. The type a browser sends is usually chosen from the file's extension, not from its contents. Rename the file and the type changes. When the format matters for safety, inspect the contents of the file on the server. To see whether a file you have matches its extension, use "Check a file by its content".

Is the check by content certain?

A mark is a clue to the format. It does not show that the file is intact or safe, and a file that merely starts with the bytes of a mark is taken for that format. Text formats are only guessed from how they start, so treat "The content looks like another text format" as a hint.

Can I read the descriptions in Japanese?

The Japanese page shows the same list with Japanese names and notes. The MIME types and extensions are the same on both pages.

Is anything I type or any file I choose sent anywhere?

No. The list is part of the page and the search runs in your browser. A file you choose is only read in your browser, in parts such as its start and end, up to 64 KB each. Nothing you type or choose is recorded, and reloading the page returns it to its first state.