# Services from lab.fastx402.tools on Zero

> lab.fastx402.tools serves 8 paid API services for AI agents, indexed by Zero. Each is callable per call with payment handled by Zero.

Canonical page: https://www.zero.xyz/host/lab.fastx402.tools
Live health (JSON, refreshed every minute): https://www.zero.xyz/host/lab.fastx402.tools/health.json

## Services

- [FastX402 Lab Holiday Date Check](https://www.zero.xyz/c/fastx402-lab-holiday-date-check-97974b53/llms.txt): $0.003/call via x402. Checks whether a specific date is a public holiday in a given country, returning holiday name, type, and metadata
- [FastX402 Lab CIDR Calculator](https://www.zero.xyz/c/fastx402-lab-cidr-calculator-e6c549d5/llms.txt): $0.002/call via x402. Computes IPv4 CIDR block details (network, broadcast, netmask, usable hosts, etc.) and optionally checks whether a given IP address falls within the block
- [FastX402 Lab BTC Fees](https://www.zero.xyz/c/fastx402-lab-btc-fees-18d14f11/llms.txt): $0.003/call via x402. Returns current Bitcoin mempool fee rates and mempool statistics for a given network (mainnet, testnet3, or testnet4)
- [FastX402 Lab Semver Match](https://www.zero.xyz/c/fastx402-lab-semver-match-02bb1461/llms.txt): $0.002/call via x402. Filters a list of semantic versions against a semver range constraint, returning all matching versions plus the highest match
- [FastX402 Lab RFC 3339 Timestamp Normalizer](https://www.zero.xyz/c/fastx402-lab-rfc-3339-timestamp-normalizer-5dc562d0/llms.txt): $0.001/call via x402. Normalizes and parses an RFC 3339 / ISO-8601 timestamp into UTC, date, time, Unix seconds/milliseconds, and UTC offset components.
- [FastX402 Lab Token Units Converter](https://www.zero.xyz/c/fastx402-lab-token-units-converter-bc956aca/llms.txt): $0.001/call via x402. Converts token amounts between human-readable decimal and blockchain atomic (integer) units given a token's decimal precision
- [FastX402 Lab Keccak256 Hasher](https://www.zero.xyz/c/fastx402-lab-keccak256-hasher-a20bc6a3/llms.txt): $0.001/call via x402. Computes the Keccak-256 hash of a given hex byte string or UTF-8 text, paid per call in USDC over x402
- [FastX402 Lab Byte-Size Parser](https://www.zero.xyz/c/fastx402-lab-byte-size-parser-fe551816/llms.txt): $0.001/call via x402. Converts a human-readable data size string (e.g. '1.5 MiB', '800 KB') into its exact byte count plus normalized SI and IEC representations

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

- [Zero catalog index](https://www.zero.xyz/llms.txt)