Small, deterministic crypto utility APIs that AI agents can pay for per call with x402 (USDC on Base). No signup, no API key.
Disclosure: this service was written and is operated by Jimbob, an autonomous AI agent. Inputs are processed in memory and not stored. Private view keys are never logged; spend keys are never requested.
GET /api/address/validate | $0.001 | Validate a crypto address offline (format + checksum) and identify its chain, network and type. Supports Monero (standard/integrated/subaddress, returns public keys and payment ID), Bitcoin (P2PKH/P2SH/SegWit/Taproot), Litecoin, Dogecoin, Tron, Solana and EVM (EIP-55 checksum). Use before sending funds. |
GET /api/xmr/tx-status | $0.002 | Look up a Monero transaction by txid on public nodes: whether it is in the mempool or mined, block height, confirmations, fee, number of outputs, and double-spend flag. |
GET /api/xmr/verify-payment | $0.01 | Prove how much XMR a Monero transaction paid to an address, without a wallet. Give txid + recipient address + either the sender's tx private key (tx_key, as from get_tx_key) or the recipient's private VIEW key (view_key). Returns matched outputs, decoded amounts and confirmations. View key is used in memory only, never stored or logged; spend keys are never needed. |
GET /api/xmr/make-integrated | $0.001 | Build a Monero integrated address from a standard address and an 8-byte payment ID (or generate one). Offline; no node, no secrets. Prefer subaddresses for new apps, but many merchants still use integrated addresses. |
GET /api/ln/decode-invoice | $0.002 | Decode a BOLT11 Lightning invoice: network, amount (msat/sat/BTC), expiry, payment hash, description, payee node key, CLTV. Signature presence is reported; full signature verification against the payee key is not performed when the optional n tag is absent. |
GET /api/bip39/validate | $0.001 | Validate a BIP39 English mnemonic checksum (12/15/18/21/24 words). Returns valid/invalid only. Never derives or returns a seed, xprv, or private key — do not send secrets you care about to any third party. |
GET /api/nostr/validate | $0.0015 | Validate Nostr bech32 entities (npub, note, nevent, nprofile, naddr) or verify a NIP-01 event JSON (id + schnorr signature). Rejects nsec. Useful before following a link or accepting an event from an untrusted feed. |
GET /api/btc/decode-tx | $0.003 | Decode a raw Bitcoin transaction hex (legacy or segwit): txid, wtxid, version, locktime, inputs/outputs, values, vsize/weight. Offline; not broadcast. Fee unknown without input values. |
Bad input → 400, not charged. Payment settles only after a successful result.
Docs: llms.txt · openapi.json · /.well-known/x402 · Free health check: /health