Blockchain.com vs MercadoBitcoin

Blockchain.com's free Explorer API returns JSON data for Bitcoin blocks, transactions, and addresses with no signup or key, alongside a Statistics/Charts API, an Exchange Rates API, and a WebSocket feed for real-time block and mempool notifications. Browser callers can opt individual GET requests into CORS by appending a cors=true parameter; this read-only data API is a separate product from Blockchain.com's API-key-gated Exchange trading API.

Mercado Bitcoin is Brazil's oldest and largest cryptocurrency exchange, operating since 2013 with spot trading across dozens of BRL pairs. Its v4 REST API and companion WebSocket service expose public market data — candles, order books, tickers — without authentication, while trading and account endpoints require an API key created from account settings. The API is free to use for individual developers.