Blockchain.com vs Gemini

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.

Gemini's REST and WebSocket APIs cover public market data (tickers, order books, trade history) alongside authenticated endpoints for order placement, account status, and FIX Drop Copy. Public market-data calls need no credentials, while trading and account endpoints require an HMAC-signed API key/secret pair with role-based permissions such as separate Trader and Fund Manager roles.