An open-source data standard for worldbuilding.
OnlyWorlds provides a universal language and supporting infrastructure for describing fictional or historical worlds across tools, games, and applications.
/schema- Core YAML definitions for 22 element categories and their fields/languages- Auto-generated exports to coding languages or frameworks (TypeScript, python, etc.)
- Main Platform - Create and manage accounts and worlds
- Documentation - Full guides and specifications
- API Reference - REST API documentation
- Discord - Community discussion
- Discussions - Feature requests and feedback
- Visual Explorer - 3D representation of infrastructure and concepts
Create a few account and your first world on onlyworlds.com, then see what tools are available to build and explore worlds.
Feedback is welcome from anyone using or interested in the standard:
- Schema requests or suggestions
- Missing features
- Tool ideas
Submit via Discord, Discussions, or the Text Tool.
You can feed the documentation, API reference, or sdk into any code-assist AI to get started. OnlyWorldsBot is tailored for OnlyWorlds development and support.
Integration libraries:
- JavaScript/TypeScript:
npm install @onlyworlds/sdk - MCP Integration:
npm install @onlyworlds/mcp-client - Python: Available on TestPyPI (PyPI release coming soon)
See developer documentation for integration guides.
Bug reports: Use GitHub Issues or create a discussion post
The REST API provides programmatic access to create, modify, and sync world data. It follows OpenAPI 3 specification and uses API-Key and API-Pin header authentication.
Open source with no commercial restrictions. Free to use, adapt, and distribute.