Guides / API Guide

Getting Started With the ProbSights API

The ProbSights API exposes Kalshi and Polymarket through one schema: a search layer for finding markets, and a historical layer for pulling the orderbook and trade record of any market you found. This walks the full path from a fresh account to real data.

1. Get a key

Create an account, then generate a key from API keys. Keys are shown once at creation — store it immediately. Authenticate with a bearer header:

Authorization: Bearer YOUR_API_KEY

2. Find a market

Search needs either q or series_id — omitting both returns 400 with the message Either q or series_id must be provided.

GET /v1/search/markets?q=bitcoin&status=active&sort_by=volume&limit=10

Each result carries market_id, exchange, question, volume, liquidity, last_yes_price, and event_id. The market_id is what the historical endpoints take.

Other useful entry points: /v1/search/events (grouped markets), /v1/search/categories (the browse tree behind /markets), and /v1/search/markets?coin=BTC for the crypto Up/Down series.

3. Pull history

GET /v1/historical/polymarket/orderbook
      ?market_id=<market_id>
      &granularity=1m
      &start_time=1737331200
      &end_time=1737417600
      &limit=1000

start_time and end_time are Unix seconds, not ISO strings. granularity accepts 1m or 5m. Swap orderbook for trades, or polymarket for kalshi, to reach the other three historical feeds.

4. Page through results

Responses are { snapshots, pagination } or { trades, pagination }. While pagination.has_more is true, resend the request with pagination_key set to pagination.pagination_key. Never page by advancing timestamps — records can share a second, so you will drop or duplicate rows.

Errors

Failures return { "message": "...", "status": 400 }. Read message rather than inferring from the status code; it names the actual problem.

Related guides

Data from Kalshi and Polymarket. Search live API docs Pricing