immudb is an immutable, cryptographically verifiable database system designed for tamper-evident storage. It provides ACID transactions with cryptographic verification via Merkle trees, ensuring data integrity and historical auditability. The system supports multiple data models: key-value, SQL (with PostgreSQL wire protocol compatibility), and document storage. Architecture follows a modular client-server design with separate binaries for server (immudb), admin CLI (immuadmin), client CLI (immuclient), and test tool (immutest). Key entry points include cmd/immudb/immudb.go (server), cmd/immuadmin/immuadmin.go (admin), and cmd/immuclient/immuclient.go (client). Data flows involve clients sending requests via gRPC or PostgreSQL wire protocol to the server, which processes transactions, appends to an immutable log, updates verification structures, and returns verifiable responses. External dependencies include Go modules for gRPC, protobuf, Viper, cryptographic libraries, and optional S3/MinIO for remote storage. The codebase demonstrates strong engineering practices with clear separation of concerns, extensive testing, and active maintenance.