A MIME type (also called a media type or Content-Type) is a label like image/png or application/json that tells browsers and servers what kind of data a file contains so they handle it correctly.

Which MIME type should I use for JSON?

Use application/json for JSON request and response bodies. It is the registered standard type and is what most APIs and clients expect.

Is anything I look up uploaded?

No. The entire reference and search runs in your browser, so nothing you type or copy is sent anywhere.

MIME Types Reference

MIME types reference — extension to Content-Type

A searchable reference that maps common file extensions to the correct MIME type (Content-Type) — from image/png and application/json to font/woff2, video/mp4 and application/octet-stream. Each row includes a short description and a one-click copy button so you can drop the exact value straight into a header or server config.

Search by extension, type or description. Everything runs in your browser; nothing is uploaded.