What is Redis?

What is Redis?

Redis is an open-source data store that keeps data primarily in memory instead of relying on disk for every read. That makes it useful when an application needs very low-latency access to frequently used or short-lived data.

Redis is more than a simple key-value store. It supports data structures such as strings, hashes, lists, sets, sorted sets, and streams. These structures can power counters, queues, leaderboards, session stores, and real-time event flows.

Common Redis Uses

• Caching: Frequently read product, page, or API responses are stored with a TTL.
• Session management: User sessions are shared across multiple application servers.
• Rate limiting: Requests per user or IP can be counted quickly.
• Queues and pub/sub: Background jobs or live notifications can be passed between services.
• Counters and scores: View counts, leaderboards, and campaign limits can be updated fast.

Business Use

Redis is often used in high-traffic web applications to reduce database load and return faster responses to users. In an e-commerce system, product details, short-lived stock checks, or campaign counters can be stored in Redis.

Because Redis is memory-oriented, it is not automatically a replacement for the main persistent database. RDB and AOF persistence options exist, but teams should decide which data can be rebuilt or lost before using it as a primary store. For document-oriented persistence, MongoDB may be a better fit; for the wider family of schema-flexible databases, see NoSQL.