The Radion API is a REST API. You use it to read Polymarket on-chain data: markets, events, and the orderbook. All the data comes from Radion’s own on-chain indexer.
Base URL
Endpoint groups
| Group | What it does |
|---|
| Authentication | Look at the API key you are using |
| Events | List events and read one event by numeric id or slug |
| Markets | List markets and read one market by condition id or slug |
| Search | Search events, topics, and profiles by text |
| Orderbook | Get the current midpoint price for an outcome token |
| Health | Check that the API is up |
Authentication
You need an API key for all /v1/* requests. Keys are free. Sign in at radion.app/dashboard to make one. Send your key in the X-API-Key header:
See Authentication for more, and Rate limits for how many requests each plan allows. Last modified on July 7, 2026