// GLOSSARY

REST API

The request/response HTTP interface a venue exposes: fetch markets, read books, place and cancel orders. Kalshi's trade API and Polymarket's Gamma + CLOB APIs are REST; pair with WebSockets for streaming and keep REST for actions and snapshots.

REST is the workhorse: you send an HTTP request, you get a JSON response. Every prediction-market integration starts here — market discovery, order book snapshots, order placement, position queries.

The venue surfaces

Kalshi serves everything from one authenticated REST API (api.elections.kalshi.com/trade-api/v2). Polymarket splits metadata (Gamma API, no auth) from trading (clob.polymarket.com, signed orders). Endpoints and schemas evolve — treat the venue docs as the source of truth.

REST vs WebSocket, practically

REST answers questions ("what's the book now?"); a WebSocket feed narrates changes. Polling REST for live data wastes rate limit budget and is always stale by one round trip, so the standard architecture is: REST for actions (place, cancel) and initial snapshots, WebSocket for everything that moves.

One REST habit worth forming early: idempotent order placement with client order IDs (see idempotency key). Full endpoint-by-endpoint walkthroughs: the prediction market API guide.