API Reference Overview

Base URL: https://api.foursec.xyz

All paid endpoints use the x402 protocol. See Authentication.

Endpoints

Method	Path	Cost	Description
GET	/price/:symbol	$0.01	Real-time aggregated price
GET	/price/history/:symbol	$0.02	Historical OHLCV data
GET	/volume/:symbol	$0.01	24h volume data
GET	/spread/:pair	$0.01	Bid/ask spread analysis
GET	/arbitrage-opportunity	$0.03	Cross-DEX arbitrage scanner
GET	/volatility-index/:symbol	$0.02	Risk metrics and volatility
POST	/price-alert	$0.05	Create webhook alert
GET	/health	Free	Health check
GET	/	Free	API info and endpoint list

Supported Symbols

BTC, ETH, SOL, ARB, OP, MATIC, AVAX, DOT, LINK, UNI

Response Format

All responses are JSON:

{
  "symbol": "ETH",
  "price_usd": 2450.32,
  "timestamp": "2026-07-04T15:30:00Z"
}

Error responses:

{
  "error": "symbol_not_found",
  "message": "Symbol XYZ is not supported"
}

Caching

• 30-second cache TTL on all paid endpoints
• Identical requests within 30s are free (no payment, no rate limit count)
• Cache headers: X-Cache: HIT or X-Cache: MISS

Rate Limits

• 100 requests/minute per wallet (standard)
• 1000 requests/minute (premium)
• Headers: X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset