Authentication

Main API: HTTP, gRPC, and QUIC

The main NextBlock API uses an API key.

• For HTTP, send the API key in the Authorization header.

• For gRPC, send the API key in the authorization metadata field.

• For QUIC, send the API key once during the initial auth handshake on the bidirectional auth stream.

authorization: your-api-key-here

TX Stream Uses Different Authentication

The TX Stream service does not use the same API-key authentication flow as the main API.

TX Stream access is tied to the Solana wallet that paid for the service, and the client authenticates by signing an auth message with that wallet.

See TX Stream API for the TX Stream-specific authentication flow.