application/json — The Standard JSON MIME Type
Learn when and how to use application/json as the Content-Type for JSON data in APIs, AJAX requests, and configuration files.
Detailed Explanation
What is application/json?
application/json is the official IANA media type for JavaScript Object Notation (JSON) data. It was standardized in RFC 4627 (2006) and later updated by RFC 8259 (2017). Whenever a server returns JSON or a client sends a JSON request body, the Content-Type header should be set to application/json.
Common HTTP Usage
Content-Type: application/json; charset=utf-8
The charset=utf-8 parameter is technically optional because RFC 8259 mandates UTF-8 encoding for all JSON, but many servers include it explicitly for clarity.
Why Not text/json?
Although text/json exists informally, it is not an IANA-registered type. Using application/json ensures proper handling by HTTP clients, API gateways, and content negotiation middleware. Browsers and libraries like fetch() and Axios recognize application/json and automatically parse the response body.
Related Types
| MIME Type | Purpose |
|---|---|
application/json |
Standard JSON |
application/ld+json |
JSON-LD linked data |
application/vnd.api+json |
JSON:API specification |
application/problem+json |
RFC 7807 error responses |
application/schema+json |
JSON Schema documents |
Content Negotiation
REST APIs commonly use the Accept header to negotiate format:
Accept: application/json
If the server supports both JSON and XML, setting this header ensures you receive JSON.
Use Case
Use application/json whenever you build or consume REST APIs, store configuration in .json files served over HTTP, or send AJAX requests from a frontend application. It is the de facto standard for web API communication.
Try It — MIME Type Reference
Related Topics
Choosing the Right Content-Type for REST APIs
Application Types
text/plain vs text/html — When to Use Which
Common Types
application/octet-stream — The Generic Binary Fallback
Common Types
application/xml vs text/xml — XML MIME Types Explained
Application Types
application/x-ndjson — Newline-Delimited JSON for Streaming
Application Types