API Documentation

Quick Start

Get started with x402 pay-per-query or an API key subscription.

curl -H "X-API-Key: your-api-key" \
  "https://api.predictingapi.com/v1/markets?category=WAR&limit=10"

No API key? Use x402 micropayments to pay $0.25 per query with USDC on Solana.

Access Tiers

PredictingAPI supports three access methods:

API Key Authentication

X-API-Key: your-api-key

x402 Payment Authentication

X-PAYMENT: solana-transaction-signature

x402 Micropayments

Pay per query with USDC on Solana. No subscription required.

How it works

1. Make a request without payment headers
2. If free tier limit exceeded, receive 402 Payment Required with payment details
3. Send USDC to the provided Solana wallet address
4. Retry request with X-PAYMENT header containing the transaction signature

402 Response Example

{
  "error": "Payment required",
  "paymentRequirements": {
    "x402Version": 1,
    "network": "solana-mainnet",
    "asset": "USDC",
    "payTo": "8hTmULLrTpXJxpebL246N4aCo4cqxHTpTrKJyRxeDdWT",
    "maxAmountRequired": "250000",
    "description": "PredictingAPI query: /markets ($0.25)"
  }
}

Pricing

Subscription: $200/month for unlimited access to all endpoints. (Coming Soon)

Base URL

https://api.predictingapi.com/v1

Endpoints

Query Parameters

Use these parameters to filter and paginate results.

• category string

  Filter by category: WAR, POLITICAL, ECONOMIC, NUCLEAR, CLIMATE, TECHNOLOGY, LEGAL, SOCIAL, PANDEMIC, CYBER, TERRORISM

• severity_min integer (0-100)

  Minimum severity score

• region string

  Geographic region: AMERICAS, EUROPE, ASIA, AFRICA, OCEANIA, GLOBAL

• limit integer (default: 20, max: 100)

  Number of results to return

• offset integer (default: 0)

  Offset for pagination

Response Format

All responses are JSON. Here's an example market object:

{
  "market_id": "polymarket_0x1d54eb...",
  "title": "Russia x Ukraine ceasefire by March 31, 2026?",
  "category": "WAR",
  "severity": 50,
  "price": 0.075,
  "volume_24h": 683413.41,
  "actors": ["Russian Federation", "Ukraine"],
  "region": "EUROPE",
  "resolution_date": "2026-03-31T00:00:00",
  "effects": [...],
  // 160+ additional fields available
}

Rate Limits

Error Codes