Look Up a Content Type
Search for an extension such as .json, a media type such as image/svg+xml, or a keyword such as document. Results show the extension, MIME type and a general category. This compact bundled mapping covers common developer and web formats. It runs locally and does not upload a file or inspect its contents.
Extensions and Media Types
An extension is a naming convention, not proof of content. Several extensions can use one media type, and some formats have more than one registered representation. XML commonly uses application/xml or text/xml; JavaScript uses text/javascript. The reference is intentionally smaller than the complete IANA registry and cannot identify arbitrary binary files.
Choose the Correct Content-Type
Use the Content-Type header that describes the actual representation. Add parameters such as charset when required by the format, and do not infer safety from an extension alone. Serving user uploads also requires a suitable download policy and content validation. The lookup offers reference information rather than a security scanner.
Standards and references
Frequently asked questions
Does this tool read or upload a file?
No. It searches a bundled mapping by the text you enter.
Is the mapping exhaustive?
No. It covers common formats; consult the IANA registry for other registered media types.
Can an extension identify a file securely?
No. Filenames can be misleading. Validate actual content and apply an appropriate serving policy.
Can one extension have multiple types?
Yes. For example, XML can be represented as application/xml or text/xml. Context and the specification determine the choice.