Bid Compression

We have the capability to send compressed (Gzip) bid requests and to decompress (Gzip) bid responses from DSPs. With bid compression, partners can see up to a 20-30% reduction in bandwidth, contributing to lower latency, infrastructure costs, and timeouts.


Bid compression is currently supported for DSPs, but is not supported for supply partners sending server-to-server requests. If you’re a DSP interested in enabling bid compression, please contact your IX Representative.

Bid Requests to DSPs

IX always passes the following field in the header for bid requests:

  • Accept-Encoding: gzip: shows DSPs that IX will accept a compressed bid response.


You can opt out of receiving the Accept-Encoding: gzip field for bid requests by contacting your IX Representative.

When bid compression is enabled, IX passes the following field in the header for bid requests:

  • Content-Encoding: gzip: shows DSPs that IX is sending a compressed bid request.

Size Requirements

To ensure we're compressing bid requests efficiently, Index Exchange (IX) only compresses bid requests over 1500 bytes. The goal is to only compress requests that require two or more packets (one packet = less than 1500 bytes) to send due to their size.

Bid Responses from DSPs

If you receive a bid request that contains Accept-Encoding: gzip, DSPs can send a compressed Gzip bid response by passing the following required fields in the header:

  • Content-Encoding: gzip: Shows IX that a DSP has sent a compressed bid response.
  • Content-Length: Shows IX the response size. To learn more, see Content-Length.


IX does not accept chunked bid responses.