> For the complete documentation index, see [llms.txt](/llms.txt)

# GS2-Gateway API Reference

WebSocket notification feature




GS2-Gateway provides a proxy function to access GS2 via WebSocket.
By using GS2-Gateway to access GS2's servers, you can communicate with them while staying connected at all times. This is expected to improve the communication speed with the server.

This will also allow for push notifications from the server side.
With this push notification functionality, you will be able to receive notifications when a task in a GS2-Mission is completed, or when the number of participants in a GS2-Matchmaking Gathering increases or decreases.

If the device being notified is offline, the system also provides a mechanism for forwarding to mobile push notifications using Firebase (https://firebase.google.com/).
With this feature, if a player is offline when matchmaking is completed, a mobile push notification can be sent out to entice the player to return to the game.

When building an always-on session with GS2-Gateway, you will need to authenticate with an access token issued by GS2-Auth to identify the game player, but you can also use the
If a session already exists for the same user, access can be denied.

[Introduction to Microservices / GS2-Gateway](../../microservices/gateway)



- [GS2-Gateway Deploy/CDK Reference](/api_reference/gateway/deploy/)
  
- [GS2-Gateway SDK API Reference](/api_reference/gateway/sdk/)
  
- [GS2-Gateway SDK for Game Engine API Reference](/api_reference/gateway/game_engine/)