# Services from api.nativebtc.org on Zero

> api.nativebtc.org serves 17 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/api.nativebtc.org
Live health (JSON, refreshed every minute): https://www.zero.xyz/host/api.nativebtc.org/health.json

## Services

- [FastPath API - Bitcoin Fee Ladder](https://www.zero.xyz/c/fastpath-api-bitcoin-fee-ladder-155726b4/llms.txt): $0.01/call via x402. Returns a tiered fee ladder (cheap/normal/urgent) with sat/vbyte estimates and block targets from Core v31 optimizer cache
- [FastPath Bitcoin Transaction Lookup (Ethereum-style RPC)](https://www.zero.xyz/c/fastpath-bitcoin-transaction-lookup-ethereum-style-rpc-e02521b3/llms.txt): $0.001/call via x402. Fetches Bitcoin transaction details — fee, vsize, and fee rate — via a REST endpoint styled for Ethereum JSON-RPC consumers.
- [FastPath Bitcoin Mempool Fee Estimator](https://www.zero.xyz/c/fastpath-bitcoin-mempool-fee-estimator-d9338b64/llms.txt): $0.001/call via x402. Returns recommended Bitcoin fee rates (sat/vB) and fee histogram data for a specified confirmation target window
- [FastPath API - Bitcoin RBF Bump Plan](https://www.zero.xyz/c/fastpath-api-bitcoin-rbf-bump-plan-056455be/llms.txt): $0.01/call via x402. Returns a Replace-By-Fee (RBF) bump plan for an unconfirmed Bitcoin transaction, including current and target fee amounts needed to reach a desired confirmation block target.
- [NativeBTC Optimized Block Template TxID List](https://www.zero.xyz/c/nativebtc-optimized-block-template-txid-list-76f12f9f/llms.txt): $0.05/call via x402. Returns an optimized, fee-maximizing ordered list of up to 4,000 transaction IDs for a Bitcoin block template, with fee uplift metrics and Ed25519 receipt metadata for Stratum V2 Job Declaration workflows.
- [FastPath API - Bitcoin Fee Estimate](https://www.zero.xyz/c/fastpath-api-bitcoin-fee-estimate-01b3f5bf/llms.txt): $0.001/call via x402. Returns a Bitcoin fee estimate in sat/vB for a given confirmation target (in blocks), sourced from Bitcoin Core's estimatesmartfee.
- [FastPath Bitcoin Mempool Transaction Lookup](https://www.zero.xyz/c/fastpath-bitcoin-mempool-transaction-lookup-b308ab64/llms.txt): $0.001/call via x402. Fetches Bitcoin mempool details for a specific transaction by txid, returning virtual size, fee rate, and RBF replaceability status.
- [FastPath API - Bitcoin Block Height](https://www.zero.xyz/c/fastpath-api-bitcoin-block-height-73b42dc6/llms.txt): $0.001/call via x402. Returns the current Bitcoin blockchain block height as both a hex string and decimal integer
- [FastPath API – Bitcoin UTXO Lookup by Address](https://www.zero.xyz/c/fastpath-api-bitcoin-utxo-lookup-by-address-4ccbd7c5/llms.txt): $0.002/call via x402. Returns the unspent transaction outputs (UTXOs) for a given Bitcoin address, paid via x402 micropayment.
- [FastPath API - Bitcoin Transaction Replacement Lookup](https://www.zero.xyz/c/fastpath-api-bitcoin-transaction-replacement-lookup-b0e7a673/llms.txt): $0.001/call via x402. Returns RBF (Replace-By-Fee) replacement history and status for a specific Bitcoin transaction by txid
- [FastPath API - Bitcoin Address Balance Lookup](https://www.zero.xyz/c/fastpath-api-bitcoin-address-balance-lookup-309b1162/llms.txt): $0.001/call via x402. Retrieves the current Bitcoin balance for a given on-chain address, returned in satoshis
- [FastPath API – Bitcoin Data via Ethereum JSON-RPC](https://www.zero.xyz/c/fastpath-api-bitcoin-data-via-ethereum-json-rpc-0d53e79f/llms.txt): $0.001/call via x402. Translates Ethereum-style JSON-RPC requests into Bitcoin blockchain data, fee estimates, mempool insights, and Bitcoin Core v31 package signals.
- [FastPath API – Bitcoin Mempool Stats](https://www.zero.xyz/c/fastpath-api-bitcoin-mempool-stats-de423d6c/llms.txt): $0.001/call via x402. Returns current Bitcoin mempool statistics including size, fee estimates by time horizon, RBF status, and network congestion level.
- [FastPath API – Bitcoin Template Check](https://www.zero.xyz/c/fastpath-api-bitcoin-template-check-5e3dc8b7/llms.txt): $0.01/call via x402. Checks whether a Bitcoin transaction is included in Bitcoin Core v31's baseline or optimized fee-estimation templates for a given block-confirmation target
- [NativeBTC Bitcoin Transaction Insight](https://www.zero.xyz/c/nativebtc-bitcoin-transaction-insight-d8dba652/llms.txt): $0.01/call via x402. Analyzes a Bitcoin transaction to produce a fee verdict, current mempool state, RBF bump plan, and Bitcoin Core v31 block template compatibility check.
- [NativeBTC Mempool Stream Ticket](https://www.zero.xyz/c/nativebtc-mempool-stream-ticket-59fc03a2/llms.txt): $0.005/call via x402. Issues a short-lived WebSocket authentication ticket granting access to the live Bitcoin mempool data stream.
- [FastPath API – Bitcoin Template Batch Check](https://www.zero.xyz/c/fastpath-api-bitcoin-template-batch-check-0f23da4d/llms.txt): $0.05/call via x402. Checks whether a batch of Bitcoin transaction IDs are included in the Core v31 optimized mempool template, given a target block confirmation window.

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)