Overview

Block (formerly block.io) provides a cryptocurrency payment and wallet API that lets developers send and receive Bitcoin and other supported coins programmatically. After creating an account and obtaining an API key, you can generate wallet addresses, query balances, and broadcast transactions. It abstracts much of the raw blockchain complexity into simple REST calls.

Beginner Tip

Obtain your API key from the Block.io dashboard under the API Keys section; you will also need your wallet PIN for any transaction-related calls. Start with the /get_balance endpoint to confirm your key is working before attempting sends.

Available Data

The kind of data this API exposes, based on its documentation. We could not call the endpoint to confirm the exact field names.

coin price in USD/EUR
market capitalization
24h price change
trading volume
circulating supply

Example Response

Illustrative shape only — we were not able to call this endpoint (it requires credentials or exposes no public sample URL), so the fields below show the kind of data this API returns rather than a recorded response.

JSON Response · Illustrative
{
  "id": "bitcoin",
  "symbol": "btc",
  "current_price": 65432.1,
  "market_cap": 1280000000000,
  "price_change_24h": 1250.5,
  "price_change_percentage_24h": 1.95,
  "total_volume": 28500000000
}

Field Reference

status Indicates success or fail for the API call.
data.network Blockchain network this wallet belongs to, e.g., BTC or LTC.
data.available_balance Confirmed balance available for spending, in full coin units.
data.pending_received_balance Incoming funds not yet confirmed by the network.
data.wallet_name Human-readable name given to this wallet in the Block.io dashboard.

Implementation Example

Calls a real endpoint of this API. Replace any placeholder credentials with your own key.

Request
const url = "https://block.io/api/v2/get_balance/?api_key=YOUR_API_KEY";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
  headers: {
  "X-API-Key": "YOUR_API_KEY"
  }
});
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

Generated guidance based on this API's documentation, not observed by us. Treat it as a starting point and check against the provider's own error reference.

403 Forbidden or "Invalid API Key" The API key does not match the network (mainnet vs. testnet) you are targeting.
Log into block.io and verify you are using the key associated with the correct network and coin (BTC, LTC, DOGE).
"PIN is required" error on send calls Transaction endpoints require a secondary authentication PIN in addition to the API key.
Pass your wallet PIN as the pin parameter in the request body — never hard-code it, use an environment variable.
Insufficient funds error The wallet balance is below the transaction amount plus network fees.
Call /get_balance first to verify available funds, and always account for dynamic network fees returned in /get_network_fee_estimate.

Metadata Score Breakdown

Estimated from metadata — endpoint not independently tested

This score is estimated from observable metadata — HTTPS support, authentication model, declared CORS, and documentation reachability — because the API requires authentication or exposes no publicly testable endpoint. The five-signal breakdown is only shown for live-tested APIs.

Metadata estimate · endpoint not independently tested

Technical Specifications

Auth API Key
HTTPS REQUIRED
CORS UNKNOWN
Category Cryptocurrency
Difficulty Intermediate
Listing details not endpoint-verified

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