Realtime Multiplayer Backend Engineer - C++ / C# Game Server

I am building a Slither.io-style browser multiplayer game with a target of up to 500 concurrent players per room. I am looking for a backend / game-server specialist to build the authoritative multiplayer server and networking layer. Main responsibilities: - Server-authoritative realtime simulation - Snake movement, boost, growth, food and collisions - Player join/leave and room management - Efficient state synchronization and delta updates - Spatial partitioning / AOI / interest management - Binary network protocol - Fixed server tick and smooth client synchronization - CPU, RAM, bandwidth and latency optimization - Load testing with 100 / 250 / 500+ concurrent bots Preferred stack: - C++20/23 preferred - C#/.NET also considered for a strong realtime multiplayer engineer - Linux - WebSocket / high-performance networking - FlatBuffers or another efficient binary protocol - Spatial grid / spatial hash / quadtree - Allocation-conscious / high-performance architecture The browser client will be built separately using TypeScript + PixiJS/WebGL2. Ideal candidate: Strong hands-on experience with: - Realtime multiplayer games - Dedicated game servers - Server-authoritative architecture - High-frequency state synchronization - Networking and performance optimization - Spatial partitioning / AOI - Load testing and profiling - 300–500+ concurrent players Please share relevant multiplayer/game-server projects, your role in them, approximate player counts, and the networking technology used. I also have Cytos as a technical reference: https://github.com/Yuu6883/Cytos It is a highly optimized single-device snake/agar-style simulation and may provide useful ideas for spatial partitioning, memory layout and simulation performance. It does not include the multiplayer networking/server architecture.