1. HTTP (Hypertext Transfer Protocol)

  1. HTTP resumable downloads
    1. Reading requests (servers)
    2. Resuming a Download
    3. Implementations
    4. References

HTTP resumable downloads

Also called Range requests, partial downloads, or partial content requests.

HTTP has a standard mechanism for being able to stop download of a file, and resume the download in a separate request. This is performed with a Range request.

This technique cannot be mixed with uploads; for implementing resumable uploads, see HTTP resumable uploads.

Reading requests (servers)

To support partial downloads, resumable downloads, and Range requests, servers merely need to support the following features:

Resuming a Download

In order to resume a download, a client needs to know the ETag or Last-Modified date according to the server, if it provided one;


  • Most Web browsers are known to use the Range header when resuming an interrupted upload.