API Key
All requests require an API key passed in the x-api-key header. Sign up free at dashboard.predexon.com.
curl -H "x-api-key: YOUR_API_KEY" \
"https://api.predexon.com/v2/polymarket/markets?limit=10"
Pay-per-call (x402)
The Data API can also be accessed via x402, the HTTP 402 Payment Required protocol. Pay per request, no signup or subscription required. Useful for agents and one-off integrations.
Facilitator: Blockrun marketplace
Plans (summary)
| Tier | Rate Limit | Monthly Requests | Price |
|---|
| Free | 1 req/sec | 1,000 | $0/month |
| Dev | 20 req/sec | 1,000,000 | $49/month |
| Pro | 100 req/sec | 5,000,000 | $249/month |
| Enterprise | Custom | Unlimited | $499+/month |
Most data is free. Core market data, historical trades, orderbooks, and pricing endpoints are free and unlimited on all plans. The Trading API is entirely free on every plan.
Exceeding rate limits returns 429 Too Many Requests. Implement exponential backoff.
Best Practices
Caching
Retry Logic
Connection Pooling
Many endpoints return data that doesn’t change frequently. Implement caching to reduce API calls:import requests, time
BASE_URL = "https://api.predexon.com"
cache = {}
CACHE_TTL = 300 # 5 minutes
def get_market(condition_id: str, api_key: str) -> dict:
cache_key = f"market:{condition_id}"
now = time.time()
if cache_key in cache and cache[cache_key]["expires"] > now:
return cache[cache_key]["data"]
response = requests.get(
f"{BASE_URL}/v2/polymarket/markets",
params={"condition_id": condition_id},
headers={"x-api-key": api_key}
)
data = response.json()
cache[cache_key] = {"data": data, "expires": now + CACHE_TTL}
return data
Implement retries with exponential backoff for transient errors:import requests
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry
session = requests.Session()
retries = Retry(
total=3,
backoff_factor=0.5,
status_forcelist=[500, 502, 503, 504]
)
session.mount("https://", HTTPAdapter(max_retries=retries))
Reuse connections for better performance:BASE_URL = "https://api.predexon.com"
session = requests.Session()
session.headers.update({"x-api-key": "your_api_key"})
# Reuse for all requests
response = session.get(f"{BASE_URL}/v2/polymarket/markets")
CORS
The API supports CORS for browser-based applications:
fetch("https://api.predexon.com/v2/polymarket/markets", {
headers: { "x-api-key": "your_api_key" }
})
.then(res => res.json())
.then(data => console.log(data));
Health Check
curl "https://api.predexon.com/health"
# {"status": "healthy"}
