How to pass match data between the Cloud Code allocator and server

To pass match data to your game server, serialize request.MatchmakingResults in your Cloud Code allocator and include it as a payload when you request the server from your hosting provider. This gives the server the full match context: player list, match ID, properties and per-player custom data.

This applies to Matchmaker pools set to Hosting via Cloud Code.

var payload = JsonConvert.SerializeObject(request.MatchmakingResults);
// Amazon GameLift: set GameSessionData = payload
// Other providers: check your provider's session creation API for the custom data field

The field name for the payload varies by provider.