Photon Engine Alternatives

Nakama is an open-source distributed social and realtime server for games and apps. It has a large set of services for users, storage, and realtime communication; as well as specialized APIs like realtime multiplayer, groups/guilds, and chat.

PlayFab is a powerful backend platform for your game.

GameSparks is a Backend-as-a-Service solution provider to mobile game developers to help them reduce the overall cost of development of their games and improve retention of their players and monetization of games post launch.

Steamworks is a free suite of tools available to any developer to use in their game or software on Steam. Here is a small sampling of the available features:

Unity Multiplayer is the way to create multiplayer games for Unity. Unity-provided servers ensure that your players can find and play with each other.

Colyseus is a Authoritative Multiplayer Game Server for Node.js. It allows you to focus on your gameplay instead of bothering about networking.

Reactor is a fully server-authoritative multiplayer system which includes integrated hosting and orchestration as well as the most efficient networking stack available.

With the Xbox Live Creators Program, anyone can integrate Xbox Live into their title and publish to Xbox One and Windows 10.

Multiplayer gaming cloud designed for Unity game developers.

DarkRift Networking is a high performance, multithreaded networking system for Unity designed for speed and flexibility. It aims to be the ideal solution for every type of game, be it a First Person Shooter, a Trading card game or a Massively Multiplayer Online game.

SmartFoxServer is a comprehensive SDK for rapidly developing multiplayer games and applications with Adobe Flash/Flex/Air, Unity, HTML5, iOS, Windows Phone 8, Android, Java, Windows 8, C++ and more.