SDKs and clients

Every client below speaks the same REST API v2. Pick by language, or by where your code runs.

Client	For	Install	State
TypeScript SDK	web apps, Node tools, browser games	npm install @onlyworlds/sdk	published on npm
Python package	scripts, pipelines, world folders	pip install onlyworlds	published on PyPI
Unity SDK	Unity games and tools	Package Manager, by git URL	public, interface not yet stable
MCP server	AI assistants and agents	nothing to install: https://www.onlyworlds.com/mcp	live
Plain REST	any other language or engine	none	live

A world’s origin, in every client. A client’s world patch call (patchWorld, patch_world, PatchWorldAsync) sends source and producer when you name them, as given; a call that accepts a folder’s world.json leaves that file’s own pair out, since there it names the folder’s maker; and setting a world’s origin from a folder is a push’s first-fill step (only when the world’s origin is empty and the folder was not exported from that same world), never the plain patch call’s.

The TypeScript, Python and Unity clients generate their element types and fields from schema-dist, the published copy of the schema. For other engines, see Games.

Plain REST

The API needs no SDK. Send the key (and, for writes, the PIN) as headers:

import requests

headers = {"API-Key": "your-key", "API-Pin": "your-pin"}
r = requests.get("https://www.onlyworlds.com/api/v2/character/", headers=headers)
characters = r.json()["data"]

List responses come back in a {data, has_more, next_cursor} envelope, so paginate on next_cursor. To generate a client in another language, start from the OpenAPI document at https://www.onlyworlds.com/api/v2/openapi.json; the interactive reference is built from the same document.

Retired

The @onlyworlds/mcp-client npm package is retired: the MCP server is hosted now, with nothing to install.