MongoDB

Booking Microservices is a practical flight-booking system developed by Evangelos Vlachos as a set of .NET 10 microservices. It uses Vertical Slice Architecture, domain-driven design, CQRS, and event sourcing; commands update PostgreSQL or EventStoreDB and publish integration events through Wolverine's durable outbox to RabbitMQ, while consumers use a durable inbox to project read models into MongoDB. Queries read from MongoDB, and synchronous cross-service validation uses gRPC. The repository includes Identity, Flight, Passenger, Booking, and YARP API gateway services, plus .NET Aspire orchestration, Docker Compose and Kubernetes deployment configurations, OpenTelemetry-based observability, OpenAPI documentation, and automated unit, integration, end-to-end, and contract tests.

Cloud Firestore is a Google Cloud-hosted NoSQL document database for storing application data, including player scores and leaderboard records. It provides a flexible schema, real-time synchronization, high availability, and scalable storage through Native mode.

LatticeDB is an embedded, single-file property-graph database written in Zig for local applications. It combines relationship traversal, HNSW vector similarity search, and BM25 full-text search in one query language and engine, allowing graph, semantic, and textual queries over the same dataset. It also provides durable named event streams and a graph changefeed through the same transaction and write-ahead-log path as graph writes. The database operates without a server or configuration and is designed for one owning process on one machine with WAL-backed durability. It is distributed through a CLI and bindings or packages for Python, TypeScript/Node.js, Java, and Go. Graph RAG, agent memory, and local knowledge tools are documented as example workloads rather than the engine's definition.

Redis is an open-source in-memory data structure server, cache, key-value and document database, and query engine for real-time applications. It supports strings, lists, sets, hashes, sorted sets, JSON, time-series data, transactions, scripting, queues, streams, publish/subscribe messaging, full-text and geospatial queries, aggregations, and vector search. The project is used for caching, distributed session storage, event brokering, real-time analytics, and as a supporting service for the support desk shown in the video.

KurrentDB is an event-native database for event-sourced and event-driven systems. It appends typed events to named streams, preserves the complete event history, streams changes in real time, and supports replaying, rewinding, or rebuilding state from past events. The service provides client libraries for Java, .NET, Go, Python, Node.js, Rust, and TypeScript, with Cloud, Enterprise, and Community deployment options.