Range Header

How Range works

A server that supports ranges advertises Accept-Ranges: bytes and answers a Range request with 206 Partial Content and a Content-Range header; a range past the end gets 416. Video and audio players depend on it: without range support, seeking doesn’t work and Safari may refuse to play the file.

Examples

Range: bytes=0-1023

Range: bytes=5000000-

HTTP/1.1 206 Partial Content
Content-Range: bytes 0-1023/146515
Content-Length: 1024

Check it

# Show the request headers curl sends (lines starting with >)
curl -sv -o /dev/null https://example.com 2>&1 | grep '^>'

Paste a full set of response headers into the HTTP header checker to get every header explained and common mistakes flagged.

Related headers

• Content-Length: gives the size of the body in bytes.
• ETag: gives a version identifier to a response, so caches can ask “has it changed?” cheaply.
• If-None-Match: asks the server to send the resource only if its ETag differs from the ones listed.

More content and negotiation headers

Content-Type , Content-Disposition , Content-Encoding , Accept , Accept-Encoding , Accept-Language , Transfer-Encoding .

Sources

• RFC 9110
• MDN: Range

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Frequently asked questions