What is the MIME type of .json files?
The MIME type (media type) for JSON files with the .json extension is application/json. You may also see text/json (obsolete). JSON is always UTF-8 (RFC 8259), so a charset parameter is unnecessary. APIs should send this type so clients and browsers parse the body as JSON.
Content-Type header
Content-Type: application/jsonText-based types should include a charset so the browser decodes characters correctly.
Server configuration
| Server | Configuration |
|---|---|
Nginx (mime.types or types {}) | application/json json; |
Apache (.htaccess) | AddType application/json .json |
IIS (web.config) | <mimeMap fileExtension=".json" mimeType="application/json" /> |
| Node.js / Express | res.type('json') or res.setHeader('Content-Type', 'application/json') |
| Amazon S3 | Set Content-Type: application/json on the object (metadata), or pass --content-type application/json to aws s3 cp |
Should .json files be compressed?
Yes. JSON is text, so enabling gzip or Brotli for application/json typically saves 50–80 % of the transfer size. Make sure your server’s compression list includes this type — check with the website compression test.
Why the MIME type matters
Browsers decide what to do with a response — render, run, play or download — from the Content-Type header, not the file extension. With X-Content-Type-Options: nosniff, a wrong type causes stylesheets and scripts to be blocked outright. For uploads, never trust the type sent by the client; check the file’s content (its magic bytes) on the server.
Frequently asked questions
What is the MIME type for .json?
application/json. Alternatives seen in the wild: text/json (obsolete).How do I set the Content-Type for .json in Nginx?
application/json json; is listed in the types block (usually in /etc/nginx/mime.types) and reload Nginx.