trade:write, a key also places and cancels paper orders. With markets:read, POST /backtest replays settled game-winner markets on paper. Optional X-Arena-Org on the portfolio and order routes selects an organization’s paper sandbox. GET /portfolio and GET /portfolio/trades then return that sandbox and organization.slug. GET /organizations lists the organizations a key belongs to. Paper orders stay in the paper book. Live Kalshi (trade:write:kalshi) and Polymarket International (trade:write:poly-intl) credentials can be saved in Settings, and live submission stays off until Arena enables it.
Get started
Making your first request
Call
/status, then /me with a key.API keys
Create, rotate and revoke
arena_sk_ keys.Authentication
Bearer header and scopes.
API reference
Every endpoint, with an interactive playground.
CLI 0.6.0
Install
arena-prediction-cli@0.6.0 and sign in.Agents
Agent kit 0.6.0: CLI, MCP server and safety rules.
Reference
Conventions
Names, units, times, identifiers and headers.
Rate limits
Plans, quotas and rate headers.
Errors
The error envelope and every code.
Specifications
OpenAPI 3.1
openapi.json, the source for the API reference.llms.txt
Short version for language models.