application/*
application/json
File extensions: .json
JavaScript Object Notation — the default data format for modern web APIs.
What is application/json?
application/json is the standard media type for JSON documents. Servers set this header when returning JSON payloads so browsers, HTTP clients, and API tooling parse the body as structured data instead of raw text. Every mainstream API — REST, GraphQL, JSON-RPC — uses it.
Typical usage
Return this from any HTTP endpoint that produces JSON. Send it in the Content-Type header when POSTing a JSON body.
Common gotchas
Charset is not part of the media type — application/json is always UTF-8 by spec (RFC 8259). Adding `; charset=utf-8` is redundant but harmless. Do not use text/json — that variant was never registered and some strict parsers reject it.
HTTP header example
Response header
Content-Type: application/json; charset=utf-8Reference
RFC 8259 (JSON) · RFC 8259 §11
Frequently asked questions
What is the application/json MIME type?
application/json is the standard media type for JSON documents. Servers set this header when returning JSON payloads so browsers, HTTP clients, and API tooling parse the body as structured data instead of raw text. Every mainstream API — REST, GraphQL, JSON-RPC — uses it.
What file extension does application/json use?
Files served as application/json typically use the extension .json. The most common is .json.
How do I set the Content-Type for application/json?
Send the HTTP response header Content-Type: application/json; charset=utf-8. Return this from any HTTP endpoint that produces JSON. Send it in the Content-Type header when POSTing a JSON body.
Is application/json an official MIME type?
Yes. application/json is officially registered with IANA (RFC 8259 (JSON) · RFC 8259 §11), so standards-conformant clients recognize it.
What are common mistakes with application/json?
Charset is not part of the media type — application/json is always UTF-8 by spec (RFC 8259). Adding `; charset=utf-8` is redundant but harmless. Do not use text/json — that variant was never registered and some strict parsers reject it.