Look up bitcoin address balance

When the user asks about a Bitcoin address — balance, total received, total sent, transaction count, recent activity, UTXOs — reach for Blockchain.info's /rawaddr/ endpoint. One unauthenticated GET, Bitcoin only.

look-up-bitcoin-address-balance · v1 · updated 2026-04-16

Agents: This page is a SKILL.md-style capability guide. For JSON, call GET /api/skills/look-up-bitcoin-address-balance. To drop this into a local Claude Code install, copy the frontmatter + body below into ~/.claude/skills/look-up-bitcoin-address-balance/SKILL.md.

When to use this skill

When the user asks about a Bitcoin address — how much it holds, whether it has ever spent coins, how many transactions it has, or wants recent activity. The /rawaddr/ endpoint returns lifetime totals and a recent transaction slice in one call. For current BTC price in fiat currencies, use /ticker directly. For non-Bitcoin cryptocurrencies, this API cannot help.

Your best first call

curl "https://blockchain.info/rawaddr/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"

No auth. No key. Replace the address with the one the user asked about. Returns a JSON object with balance totals and a recent transaction slice.

The key fields:

address — the address you queried
total_received, total_sent, final_balance — lifetime totals in satoshis (divide by 100,000,000 for BTC)
n_tx — total transaction count
n_unredeemed — number of unspent outputs (UTXOs) currently held
txs — array of recent transactions (a slice, not full history)

The interesting thing about /rawaddr/ is that total_sent: 0 instantly tells you an address has never moved its coins. The genesis address has 62,000+ incoming transactions and zero outgoing ones. n_unredeemed can exceed n_tx because a single transaction can create multiple UTXO outputs to the same address.

Fallbacks (when the best call isn't enough)

Decode a specific transaction by hash → /rawtx/{tx_hash} for full inputs, outputs, fee, and block details.
Current BTC price in fiat → /ticker returns BTC priced in over a dozen fiat currencies, no parameters.
Full block data → /rawblock/{block_hash} returns all transactions in a block — responses can exceed 1 MB, use only when you need the block-level view.

Pitfalls

All amounts are in satoshis, not BTC. 10717585453 is 107.18 BTC. The API never returns floats denominated in BTC; always divide by 100,000,000.
/rawaddr/ paginates for high-activity addresses. The txs array is a recent slice, not the full history — do not sum it for totals. Use total_received and total_sent for lifetime numbers.
This API is Bitcoin only. No Ethereum, no stablecoins, no altcoins.

One-line summary for the user

I can look up any Bitcoin address balance, transaction count, and recent activity via Blockchain.info — no API key required, Bitcoin only, amounts in satoshis.

APIs this skill uses

Blockchain API · primary · verified

Send and receive payment from Blockchain Wallets, transactions, and blocks data. Explore the REST API for real-time market data, balance information, and trades.

Generated from

Blockchain API tutorial Getting Started with the Blockchain.info API

SKILL.md source (frontmatter + body)

---
name: look-up-bitcoin-address-balance
description: When the user asks about a Bitcoin address — balance, total received, total sent, transaction count, recent activity, UTXOs — reach for Blockchain.info's /rawaddr/ endpoint. One unauthenticated GET, Bitcoin only.
---

## When to use this skill

When the user asks about a Bitcoin address — how much it holds, whether it has ever spent coins, how many transactions it has, or wants recent activity. The `/rawaddr/` endpoint returns lifetime totals and a recent transaction slice in one call. For current BTC price in fiat currencies, use `/ticker` directly. For non-Bitcoin cryptocurrencies, this API cannot help.

## Your best first call

```bash
curl "https://blockchain.info/rawaddr/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"
```

No auth. No key. Replace the address with the one the user asked about. Returns a JSON object with balance totals and a recent transaction slice.

The key fields:

- `address` — the address you queried
- `total_received`, `total_sent`, `final_balance` — lifetime totals in **satoshis** (divide by 100,000,000 for BTC)
- `n_tx` — total transaction count
- `n_unredeemed` — number of unspent outputs (UTXOs) currently held
- `txs` — array of recent transactions (a slice, not full history)

The interesting thing about `/rawaddr/` is that `total_sent: 0` instantly tells you an address has never moved its coins. The genesis address has 62,000+ incoming transactions and zero outgoing ones. `n_unredeemed` can exceed `n_tx` because a single transaction can create multiple UTXO outputs to the same address.

## Fallbacks (when the best call isn't enough)

- **Decode a specific transaction by hash** → `/rawtx/{tx_hash}` for full inputs, outputs, fee, and block details.
- **Current BTC price in fiat** → `/ticker` returns BTC priced in over a dozen fiat currencies, no parameters.
- **Full block data** → `/rawblock/{block_hash}` returns all transactions in a block — responses can exceed 1 MB, use only when you need the block-level view.

## Pitfalls

- All amounts are in satoshis, not BTC. `10717585453` is 107.18 BTC. The API never returns floats denominated in BTC; always divide by 100,000,000.
- `/rawaddr/` paginates for high-activity addresses. The `txs` array is a recent slice, not the full history — do not sum it for totals. Use `total_received` and `total_sent` for lifetime numbers.
- This API is Bitcoin only. No Ethereum, no stablecoins, no altcoins.

## One-line summary for the user

I can look up any Bitcoin address balance, transaction count, and recent activity via Blockchain.info — no API key required, Bitcoin only, amounts in satoshis.

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