About godot-tiny-mmo

Open-source cross-platform MMORPG built with Godot 4

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README.md

[!NOTE] Documentation & Guides: slayhorizon.github.io/godot-tiny-mmo/
Latest research note: Byte-Level Networking Protocol for MMO Scalability

Godot Tiny MMO

Experimental open-source MMORPG framework built with Godot 4.
Inspired by proven MMO systems, this project pushes the boundaries of what can be achieved with Godot in large-scale multiplayer.
It explores scalable multiplayer architecture and efficient byte-packed networking, while remaining clear and approachable as a learning project.

Cross-platform: browser + desktop + mobile
Unified codebase: Client & multiple servers in one repo
- Faster iteration, develop in one place, test in one click
- Separate export presets for clean client/server builds
"Custom netcode" but stay simple
- No reliance on Godot’s MultiplayerSynchronizer/Spawner
- ID-based, byte-packed protocol (PackedByteArray instead of string-based messages) for efficient replication
- Built to support interpolation, multi-map instances, and seamless transitions
True MMO-style architecture
- Gateway server: authentication & routing
- Master server: orchestrator, account management & bridge between gateways and world servers
- World server: host multiple concurrent maps and instances; the place where gameplay actually happens

See more screenshots:

architecture-diagram

Features

See current and planned features:

[X] Client-Server connection through WebSocketMultiplayerPeer
[x] Playable on web browser and desktop
[x] Network architecture (see diagram below)
[X] Authentication system through gateway server with Login UI
[x] Account Creation for permanent player accounts
[x] Server Selection UI to let the player choose between different servers
[x] SQLite persistence (players, guilds, chat)
[x] Guest Login option for quick access
[x] Game version check to ensure client compatibility
[x] Character Creation
[x] Basic RPG class system with three initial classes: Knight, Rogue, Wizard
[x] Weapons at least one usable weapon per class
[x] Basic combat system
[x] Friend list
[x] Guild
[X] Entity synchronization for players within the same instance
[ ] Entity interpolation to handle rubber banding
[x] Instance-based chat for localized communication
[X] Instance-based maps with traveling between different map instances
- [x] Three different maps: Overworld, Dungeon Entrance, Dungeon
- [ ] Private instances for solo players or small groups
[ ] Server-side anti-cheat (basic validation for speed hacks, teleport hacks, etc.)
[x] Server-side NPCs (AI logic processed on the server)
[x] Interest management (AOI filtering using grid on large maps)
[x] Web-based admin dashboard (monitor servers, instances, and connections)

Getting Started

To run the project, follow these steps:

Open the project in Godot 4.6.
Go to Debug tab, select "Customizable Run Instance...".
Enable Multiple Instances and set the count to 4 or more.
Under Feature Tags, ensure you have:
- Exactly one "gateway-server" tag.
- Exactly one "master-server" tag.
- Exactly one "world-server" tag.
- At least one or more "client" tags.
(Optional) Under Launch Arguments:
- For servers, add --headless to prevent empty windows.
- For any, add --config=config_file_path.cfg to use non-default config path.
Run the project (Press F5).

Setup example (More details in the wiki How to use "Customize Run Instances...":

Contributing

Feel free to fork the repository and submit a pull request if you have ideas or improvements!
You can also open an Issue to discuss bugs or feature requests.

Credits

Thanks to everyone who made this project possible:

Maps designed by @higaslk
Valuable help and feedback: @Jackiefrost, @d-Cadrius and multiple anonymous contributors
Also @Anokolisa for allowing us to use its assets for this open source project!

License

Source code under the MIT License.

godot-tiny-mmo