Test whether a RE2 pattern matches anywhere in the input. Returns { matched }. RE2 guarantees linear-time evaluation, so this is safe against catastrophic backtracking. An invalid pattern is a clean 400; no match is a successful 200.

Evaluate a mathematical expression with optional named variables — arithmetic, comparison and logic operators plus functions like sqrt, abs, min, max, sin, cos, log, floor, round, etc. A syntax error, an undefined variable, or a non-finite result is a clean 400. The factorial operator is disabled for safety.

Validate an ISBN-10 (mod-11, trailing X allowed) or ISBN-13 (GTIN mod-10) book number. Length after removing spaces/hyphens selects the scheme.

Parse any CSS color and return it as hex, rgb, hsl, hwb, lab, lch and oklch.

Return the ISO weekday (1=Monday..7=Sunday) and its name for a Gregorian date.

Parse an expression and return the free variables it references, without evaluating it — so an agent can discover which inputs a formula needs before supplying values. A syntax error is a clean 400.

Check whether a specific date is a public holiday in a country (optionally by state/region).

Validate a 9-digit US ABA bank routing number by its weighted (3,7,1) mod-10 checksum. Spaces and hyphens are ignored.

Validate a Finnish VAT (ALV) number against the official VAT register. Validity means the entity exists and holds a live registration.

Parse an IPv4 or IPv6 address and classify it — version, normalized form and RFC range (unicast, private, loopback, linkLocal, multicast, uniqueLocal, ipv4Mapped, …). Detects IPv4-mapped IPv6.

Derive the modified EUI-64 interface identifier from a 48-bit MAC (insert FFFE, flip the U/L bit) and the resulting IPv6 link-local address (fe80::/64).

Reverse-resolve an IPv4 or IPv6 address to its PTR hostname(s). No PTR record returns an empty list. This is reverse DNS (PTR) — not ENS or onchain name resolution.

Live recommended Bitcoin transaction fee rates (in sat/vB) for next-block, ~30-minute, ~1-hour, economy and minimum confirmation targets, straight from the mempool. Also estimates the total fee (in sats and BTC) for a transaction of the given virtual size, so an agent can pick a fee tier and know the cost before broadcasting.

Latest version, Python requirement, licence, dependencies and the advisories against the current release of a PyPI project.

Live transaction receipt by hash via `eth_getTransactionReceipt`: success/failed status, block number, from/to, created contract address, gas used, cumulative gas, effective gas price (wei + gwei), tx type and the emitted event logs (capped). Complements `tx` (which reads the transaction itself). Returns `found:false` for unknown/pending hashes. Reads live on-chain data with automatic endpoint fallback.

Live snapshot of the Bitcoin mempool: number of unconfirmed transactions, total pending virtual size (bytes and MB), the current backlog in blocks, total fees pending (sats and BTC), the fee-rate histogram, and the current chain tip height. Lets an agent gauge network congestion and time a transaction.

Live status and details of a transaction by hash: success/failed/pending, from/to, value (wei + ether), nonce, block number, gas used, effective gas price and any created contract address. Returns `found:false` for unknown hashes. Reads live on-chain data with automatic endpoint fallback.

Reverse-resolve an Ethereum address to its primary ENS name (the reverse record set by the owner), read live on Ethereum mainnet. Returns `found:false` when the address has no primary name set. Live reads with automatic endpoint fallback.

Verify a factual claim against fresh web evidence with a support/conflict verdict.

Live block summary by number, hex, or tag (latest/earliest/pending/safe/finalized; default latest): number, hash, parent, timestamp (unix + ISO), transaction count, gas used/limit, base fee and miner. Reads live on-chain data with automatic endpoint fallback.