FastX402 Lab

Endpoints (8 live)

• GET /btc-fees — Returns current recommended Bitcoin fee rates in sat/vB for fastest, 30-minute, 1-hour, and economy confirmation targets, plus mempool transaction count and vsize. Use it to price a transaction or report network congestion right now. (0.003 USDC on Base)
• GET /byte-size-parse — Accepts a file-size string such as 1.5 MiB, 800 KB, or 42 bytes and returns the exact byte count, detected unit system, and normalized IEC and SI forms. Use it when converting human-readable storage values. (0.001 USDC on Base)
• GET /semver-match — Accepts a comma-separated list of semantic versions and a semver constraint such as ^2.4.0 or >=1.5.0 <2.0.0, then returns matching versions and the highest match. Use it for dependency and release checks. (0.002 USDC on Base)
• GET /rfc3339-normalize — Accepts an RFC 3339 or ISO-8601 timestamp and returns its canonical UTC form, Unix seconds, date, time, and UTC offset. Use it to normalize timestamps before comparison or storage. (0.001 USDC on Base)
• GET /cidr-calc — Takes an IPv4 CIDR block like 10.0.0.0/22 plus an optional IP and returns network address, broadcast, netmask, wildcard, first and last usable host, usable host count, and whether the IP falls inside the block. Handles non-octet boundaries and /31, /32 edge cases. (0.002 USDC on Base)
• GET /holiday-date-check — Checks whether a supplied date is a public holiday in a country and year, returning the holiday name and observed-date details when available. Use it for deadline, scheduling, and business-day workflows. (0.003 USDC on Base)
• GET /keccak256 — Keccak-256 hash (the Ethereum hash, not SHA3-256) of UTF-8 text or of hex bytes. Use it for Solidity storage keys, event topics, commitments or checking a hash an agent computed. (0.001 USDC on Base)
• GET /token-units — Exact conversion between a token's decimal amount and its integer base units (wei, USDC atomic units...) for any decimals 0-36. No floating point. Use it before signing a transfer or reading a balance. (0.001 USDC on Base)