Ryzom (also known as The Saga of Ryzom) is a free and open source massively multiplayer online role-playing game set on Atys, a science-fantasy world built from the gigantic, interlocking roots of a planet-sized plant. Developed by Nevrax and first released in 2004, Ryzom was released as open source in 2010 — client, server, tools and game media alike — making it one of the very few commercial-grade MMORPGs whose entire codebase is public. It is free to play on Windows, macOS and Linux.

Key Features

• Classless skill system — there are no character classes: develop fighting, magic, crafting and harvesting on a single character and spend skill points wherever you like.
• Stanza-based action building — assemble your own spells and attacks from components (stanzas) that define each action’s effects, costs and restrictions, instead of picking from a fixed spell list.
• Living, seasonal world — Atys has five lush ecosystems whose landscape, wildlife behaviour and harvestable materials all change with season, weather and time of day.
• Realistic wildlife AI — carnivores hunt in packs, herbivores graze in herds, and whole species migrate when the seasons turn.
• Deep harvesting and crafting — prospect for hidden deposits, dig materials whose quality depends on your skill, the site and the season, then combine them into thousands of possible weapons and armour.
• Consensual PvP — duels, outpost battles and faction conflicts are all opt-in; outside marked zones you cannot be attacked against your will.
• Kitin invasions and live events — large-scale invasions and official interactive events with responsive NPCs whose outcome depends on what players actually do.
• Fully open source — engine, client, server, tools and art assets are published under open licences, and a scenario editor lets players design their own regions for the official server.

Why Use Ryzom?

Ryzom is unusual among MMOs because it is genuinely open source rather than merely free to play: the game’s code and assets were released to the community in 2010 and are kept alive by contributors. There are no classes to lock you into a role and no forced faction, so the game rewards experimentation — one character can learn any skill. Because the world reacts to seasons, weather and player-driven events, it genuinely feels different a month later. It also offers an organic, plant-based world that looks like nothing else in the genre.

Use Cases

• Playing a full, persistent MMORPG without a subscription or up-front purchase.
• Roleplay-heavy adventuring in a mature, multilingual community with regular official live events.
• Exploring or contributing to one of the few fully open-sourced MMORPG codebases (client, server and assets).
• Harvesting and crafting as an economic endgame: gathering rare materials and building bespoke gear.

Platform

Windows · macOS · Linux

Licence

Free and open source — the Ryzom Core engine, client, server and tools are published under the GNU AGPL v3.0, while the game’s art assets are released under Creative Commons licences. Ryzom is free to play, and the official servers are run and funded by the community.

Website

ryzom.com · Source code: github.com/ryzom/ryzomcore

Similar Open Source Tools

Prefer a voxel sandbox you can explore and build in with friends? See Veloren — an open-source multiplayer voxel action-adventure RPG.