Range

What is the Range header?

The Range request header, defined in RFC 9110, asks the server to return only a portion of a resource instead of the whole thing. It is most commonly expressed in bytes, letting clients fetch a specific slice of a file.

API Usage & Best Practices

• Resumable downloads: Clients can request the bytes they are missing (for example after a dropped connection) rather than starting the transfer over from scratch.
• Streaming & seeking: Media players use ranges to jump ahead in audio or video without downloading everything before that point.
• Handle the responses: A successful partial request returns 206 Partial Content. If the requested range cannot be satisfied, the server responds with 416 Range Not Satisfiable; a server that ignores the header simply returns the full resource with 200 OK.

Examples

GET /video.mp4 HTTP/1.1
Host: cdn.example.com
Range: bytes=0-1023