Authentication

Send your dashboard API key in the X-API-Key header on every /v1 request.

All /v1 endpoints require an API key. There is no unauthenticated public tier on these routes.

1. Create a key

   Sign in to the PolymarketData dashboard and create an API key.

2. Send it on every request

   Use the X-API-Key header:

   X-API-Key: pk_live_your_key_here
   

curl

curl "https://api.polymarketdata.co/v1/health" \
  -H "X-API-Key: pk_live_your_key_here"

Python SDK

The SDK reads POLYMARKETDATA_API_KEY automatically. You can also pass the key explicitly:

from polymarketdata import PolymarketDataClient

with PolymarketDataClient(api_key="pk_live_your_key_here") as client:
    print(client.utility.health().status)

Keep live keys out of notebooks, git, and client-side apps. Use an environment variable or a secret manager.

Failed authentication

Status	Meaning
401	Header missing, key invalid, or key expired
403	Key is valid, but the plan does not allow this resolution, lookback, or data point
429	Rate limit exceeded for this key

Missing key:

{ "detail": "API key is required. Include 'X-API-Key' header." }

Invalid or expired key:

{ "detail": "Invalid or expired API key." }

See Errors and limits for plan 403 and rate-limit 429 handling.

Call GET /v1/usage after you authenticate. It returns your plan name, remaining requests, allowed granularity, and which of metrics, prices, and books you can query.