Bitcoin address balance API: confirmed, pending, received and sent

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Bitcoin address balance and activity for any mainnet address (legacy, P2SH or bech32): confirmed balance in sats and BTC, unconfirmed pending amount, total received and sent, and transaction counts. Use for payment verification, checking whether a deposit arrived, and wallet monitoring.

When to use it

Guide: Bitcoin fee estimate API

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

Bitcoin mainnet address (1..., 3... or bc1...)

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
address (required)stringBitcoin mainnet address (1..., 3... or bc1...)

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/btc-address?address=bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/btc-address?address=bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "network": "bitcoin",
  "address": "bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh",
  "balanceSats": 392247777,
  "balanceBtc": 3.92247777,
  "pendingSats": 0,
  "totalReceivedBtc": 16.79253616,
  "totalSentBtc": 12.87005839,
  "transactions": 1138,
  "pendingTransactions": 0
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is btc_address, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

Which address types?

Bitcoin mainnet legacy, P2SH and bech32 addresses.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.

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