Step 1 — Get an API key
1
Sign up at dashboard.predexon.com
No credit card required. The free plan gives you 1,000 requests/month against the entire Data API — enough to evaluate everything.Open dashboard →
2
Copy your key
One key covers everything. It goes in the
x-api-key header of every request.Step 2 — Make your first call
This call lists the top 5 trending markets on Polymarket. It works on the free plan with no setup.Step 3 — Pick your path
Now go to the guide for what you’re building.Quant / data trader
Backtest with orderbook history, build smart-money models, stream live signals. Most of what you need is on the free tier.
App builder / platform
Architecture patterns for products built on prediction-market data — one API across every venue.
Active trader / fund
The data-driven trading loop. Discover, signal, backtest, size, monitor.
AI agent developer
Drop the MCP server into Claude, Cursor, or Codex. Five recipes for common agent tasks.
What’s on each surface
Troubleshooting
401 / 403 errors
401 / 403 errors
- Verify your key is in the
x-api-keyheader (lowercase, hyphenated). - Free plan can’t hit Smart Money, Binance, or WebSocket — those need Dev or higher.
- WebSocket connection rejected? Same gating — see Rate Limits.
429 Too Many Requests
429 Too Many Requests
You’ve hit your rate limit. Free is 1 req/s, Dev is 20 req/s, Pro is 100 req/s. Implement exponential backoff. See Best Practices for the pattern we recommend.
Empty results
Empty results
Most list endpoints accept
status, sort, limit parameters — try removing filters one at a time. Markets that were resolved more than a few weeks ago may be archived and need ?archived=true.Where do I see all endpoints?
Where do I see all endpoints?
Every endpoint is documented under Data & Signals. Each page has an interactive playground.
Need help?
Discord
The fastest way to get unblocked. Engineering reads every message.
team@predexon.com for anything that doesn’t fit Discord.