This repository implements a production-grade gRPC streaming service for Solana blockchain data, known as the Geyser plugin. It runs as a plugin within the Agave (Solana validator) process, intercepting internal validator events (account updates, transactions, slots, blocks, gossip, block footers) and streaming them to external clients over gRPC. The system supports real-time subscriptions with per-client filtering (memcmp, lamports, cuckoo filters, token account expansion), multiple commitment levels (Processed/Confirmed/Finalized), block reconstruction from fragmented events, and transparent reconnection with bank-level recovery. It is built in Rust using the tokio async runtime and the tonic gRPC framework, with client libraries in Rust and Node.js (via N-API native bindings). The architecture consists of several crates: yellowstone-grpc-geyser (server plugin with authentication, rate limiting, billing, Prometheus metrics, and TLS support), yellowstone-grpc-client (Rust client with auto-reconnect and deduplication), yellowstone-grpc-proto (protobuf definitions and a custom cuckoo filter implementation), yellowstone-grpc-tools (reusable server components like interceptors, rate limiters, and TLS resolvers), and yellowstone-grpc-e2e-test (end-to-end test harness with parameterized scenarios). The system is designed for low-latency, high-throughput data distribution and includes extensive observability, configuration validation, and CI/CD pipelines. Key entry points include the Geyser plugin entry (yellowstone-grpc-geyser/src/lib.rs), the config-check CLI binary, the Rust client builder (GeyserGrpcBuilder), and the Node.js SDK (Client class). The primary data flow is: Solana validator callbacks → plugin message conversion → block reconstruction → filtered gRPC streams per subscription. External dependencies include the Agave validator, tonic, tokio, prost, and various Solana crates. The codebase is actively maintained with frequent releases, pinned toolchains, and comprehensive integration tests.