Client software back off

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for limiting load on host servers that implement a social messaging platform. An example user device sends, to a platform comprising a plurality of host servers, a first request. The request is directed to a first endpoint. The user device receives, in response to the first request, a first error that indicates that the first request was not processed. The user device determines a back off time and places subsequent requests to the platform that are initiated before the back off time elapses and that are directed to the first endpoint in a back off queue in an order in which the subsequent requests are initiated. The user device sends, to the platform, the requests in the back off queue after the back off time has elapsed, until the back off queue is empty.