MIME Types Reference

MIME (Multipurpose Internet Mail Extensions) type is a standard identifier used to indicate the nature and format of a document, file, or assortment of bytes. It consists of a type and subtype, e.g. 'text/html' or 'application/json'. Servers and browsers use MIME types to determine how to process files.

Set the Content-Type HTTP header to the appropriate MIME type. For example: Content-Type: application/json; charset=utf-8. Web servers like Apache and Nginx can map file extensions to MIME types automatically. In Express.js, use res.type('json') or res.setHeader('Content-Type', 'application/json').

application/json is the official IANA-registered MIME type for JSON data and should always be used. text/json is non-standard and was used historically. Modern APIs, frameworks, and browsers all expect application/json for JSON payloads.

Use application/octet-stream as a generic binary download type, which forces browsers to download rather than display the file. For specific formats use the appropriate type (e.g. application/pdf for PDFs). Combine with Content-Disposition: attachment; filename='file.ext' for a download prompt.