Authentication

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.

For the full matrix — WebSocket limits, gated features, free-endpoint list, overage pricing — see Rate Limits & Plans (the canonical reference) or predexon.com/pricing.

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"}

Welcome

Guides for your use case

Cookbook

Core concepts

Account & access

Integrations

API Key

Pay-per-call (x402)

Plans (summary)

Best Practices

CORS

Health Check

​API Key

​Pay-per-call (x402)

​Plans (summary)

​Best Practices

​CORS

​Health Check

API Key

Pay-per-call (x402)

Plans (summary)

Best Practices

CORS

Health Check