HTTP headers

Request header

Our OpenRTB bidding API uses HTTP 1.1 protocol and sends the following request headers:

Attribute	Scope	Description
`Connection`	Required	The connection type for the request. We accept "`Keep-Alive`".
`Content-Length`	Required	The size of the request.
`Content-Type`	Required	The content type for the request. This value is always "`application/json`".
`Host`	Required	The domain of the bidding URL.
`x-openrtb-version`	Required	The version of OpenRTB protocol used for the request. Index defaults to sending `"2.6"`, unless a DSP is not capable of receiving that value. OpenRTB bid requests are backward compatible with OpenRTB 2.5 requests. Note: While we send `"2.6"` as the default value, Index currently only supports the functionality associated with a subset of OpenRTB 2.6 fields, as documented in our List of supported OpenRTB bid request fields for DSPs. Support for additional fields is ongoing. For more information on supported OpenRTB 2.6 fields as they are released, see our Release Notes.
`Content-Encoding: gzip`	Required	Specifies that the payload in the request body utilizes gzip compression. For more information about gzip, see Send and receive compressed traffic using gzip.

The Index OpenRTB bidding API uses HTTP 1.1 protocol and sends the following response headers:

Attribute	Scope	Description
`Content-Length`	Optional	Specifies the size of the response.
`Connection`	Optional	The connection is closed after processing the request if the value is "`close`". Otherwise, the connection is reused for the following request.

To express a "no-bid", you may return an empty bid response with HTTP Status Code 204 "No Content".