FerresDB is a high-performance vector database engineered in Rust, designed to deliver sub-millisecond search latencies and robust scalability for AI-driven applications. It seamlessly integrates vector search with BM25 text retrieval, supports multiple protocols including REST, gRPC, and WebSocket, and offers advanced features like tiered storage and role-based access control. Key Features and Functionality: - Sub-Millisecond Latency: Achieves P50 search latencies between 100–500 microseconds, ensuring rapid query responses. - Hybrid Search Capabilities: Combines dense vector search with BM25 text retrieval using weighted fusion or Reciprocal Rank Fusion (RRF) for enhanced precision. - Multi-Protocol Support: Offers REST API for simplicity, gRPC with bidirectional streaming for high throughput, and WebSocket for real-time applications, all running concurrently. - Tiered Storage Architecture: Automatically manages data across Hot (RAM), Warm (memory-mapped), and Cold (disk) storage tiers based on access frequency, optimizing performance and cost. - Advanced Quantization Techniques: Utilizes SQ8 scalar quantization, QJL residual correction, and PolarQuant encoding to reduce memory usage and improve recall rates. - Graph Exploration: Supports native point-level graphs, enabling traversal of subgraphs via breadth-first search (BFS) and combining graph proximity with vector similarity for enriched results. - Observability and Monitoring: Provides Prometheus metrics, query profiling, slow query tracking, and a built-in web dashboard for comprehensive system monitoring. Primary Value and User Solutions: FerresDB addresses the critical need for efficient and scalable vector search solutions in AI-native applications. By delivering ultra-low latency searches, hybrid retrieval methods, and flexible deployment options, it empowers developers to build and scale applications such as semantic search engines, retrieval-augmented generation (RAG) pipelines, recommendation systems, and knowledge graphs. Its robust architecture and advanced features ensure reliability, security, and performance, making it an ideal choice for enterprises seeking to enhance their AI capabilities.