Blockbook Endpoints (UTXO Indexers)

Blockbook exposes a unified REST/WebSocket schema for UTXO chains—balances, UTXOs, mempool, and transaction broadcast—making multi‑chain Bitcoin‑style clients simpler to build. We surface Blockbook‑compatible endpoints for multiple networks including Arbitrum (for consistent tooling where available), Bitcoin, and Testnet. Treat these as indexer APIs optimized for wallets and explorers; they complement but do not replace raw full‑node RPC for consensus‑critical operations.