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206

Partial Content

2xx Success

.md

ELI5

You asked for just a piece of a file (like pages 5-10 of a book), and here's that specific piece you wanted!

Server perspective

Use 206 when a valid Range request asks for one or more portions of a representation.

When to use

  • •Return 206 for resumable downloads, media seeking, and partial fetches
  • •Use it only when the request included a satisfiable range
  • •Video/audio streaming with range requests
  • •Large file downloads that support resume functionality
  • •PDF page range requests
  • •Image tile serving for maps or large images
  • •Any scenario where clients request specific byte ranges

How to respond

  • •Include Content-Range for single-range responses
  • •Use multipart/byteranges when returning multiple ranges
  • •Do not send a top-level Content-Range header on multipart responses; each body part carries its own Content-Range

Headers to consider

  • •Content-Range
  • •Accept-Ranges
  • •Content-Type
  • •If-Range — sent by the client to make the range request conditional; validate it before responding with 206 to avoid delivering partial content from a stale representation.

Response body

  • •Return the requested range bytes, or multipart body parts for multiple ranges

Server-side pitfalls

  • •Do not use 206 when the client did not ask for a range
  • •Return 416 instead when the requested range cannot be satisfied
  • •Do not send a top-level Content-Range header together with a multipart/byteranges response
  • •When no Range header was provided (use 200 OK)
  • •When the Range request is invalid (use 416 Range Not Satisfiable)
  • •For small files where partial content doesn't make sense
  • •When the server doesn't support range requests

Examples

Video streaming

Request:GET https://api.example.test/video.mp4 # Headers Range: bytes=1000000-2000000
Response:206 Partial Content # Headers Content-Range: bytes 1000000-2000000/50000000 # Body <partial representation>

The server returns only the requested portion of the file instead of the entire video.

Resume file download

Request:GET https://api.example.test/largefile.zip # Headers Range: bytes=5242880-
Response:206 Partial Content # Headers Content-Range: bytes 5242880-10485759/10485760 # Body <partial representation>

The client resumes a download from byte 5 MB instead of starting the transfer over.

References

Related Status Codes

200

OK

Everything worked perfectly! The server understood your request and sent back exactly what you asked for.

416

Range Not Satisfiable

You asked for a specific part of a file (like pages 50-60), but the file only has 10 pages. I can't give you what doesn't exist.