Redis

Redis (Remote Dictionary Server) is an open-source, in-memory data structure store used as a database, cache, and message broker. It achieves sub-millisecond response times through in-memory storage and supports strings, hashes, lists, sets, sorted sets, streams, and geospatial indexes.

Role in NestJS

Redis serves two primary roles in NestJS applications:

• Caching: Frequently accessed data (database query results, API responses) is stored in Redis to reduce latency and database load. Both the CacheModule/CacheInterceptor approach and direct ioredis integration are supported.
• Message broker: Through the Redis Transporter, NestJS microservices can communicate via Redis pub/sub channels.

Connection and configuration

• Default host: localhost, default port: 6379
• Connections can be managed via OnModuleInit/OnModuleDestroy lifecycle hooks, or through NestJS’s CacheModule.register().
• Supports connection pooling, clustering, and sharding for high availability.

TTL and expiry

Redis supports per-key expiry via the EX option (in seconds). Common TTL values in NestJS caching patterns range from 10 minutes (short-lived tokens) to 30 minutes (product data) to 1 day (stable reference data).