# Skylark Liquidity Intelligence API
Official names: Financial Liquidity Proxy (FLP), Financial Liquidity Index (FLI), Global Funding Conditions (GFC).
Production: https://api.skylarkdigitalassets.com
Mainnet: Base eip155:8453 (USDC, x402).
Read-only live status: https://skylark-liquidity-api-portal.vercel.app/launch-health
Mainnet products: 3 current readings, current bundle, 52/260-week single-index and bundle histories.
Sandbox: https://sandbox-api.skylarkdigitalassets.com (Base Sepolia, prior x402 test payment verified).
OpenAPI: https://skylark-liquidity-api-portal.vercel.app/openapi.json
Get /source-health first. An unpaid GET returns HTTP 402 only when source data is ready. Inspect PAYMENT-REQUIRED and verify the exact amount, recipient, network and USDC contract before payment. A live mainnet settlement and data-delivery transaction has not yet been independently accepted; Bazaar external catalog registration is unverified.
Customer fields: official_name, value, as_of (or readings of those fields). Never disclose internal formula, weights, source datasets or calculation steps.