In the world of system design, the statement ‘Redis is faster than Kafka’ is a common talking point,
but it requires a closer look.
Redis is a fast in memory data store used to keep data that needs quick access. It is commonly used for caching, message queues, session storage, and real-time analytics. Redis stores data in RAM, which makes it much faster than traditional databases.
As Redis operates primarily in memory. This allows it to deliver messages in sub-millisecond times. It is an excellent choice for real-time applications like chat systems, live scoreboards, or quick job
queues where immediate delivery is critical and data persistence is secondary.
Apache Kafka is a distributed messaging platform used to send, store, and process large amounts of data in real time. It is commonly used for event streaming, log collection, and data pipelines. Kafka is designed to be reliable, scalable, and able to handle high data volumes.
Apache Kafka, on the other hand, is designed for throughput(volume) and durability.It writes logs to disk to ensure zero data loss and allows for message replay. While its latency is slightly higher (typically 2ms to 10ms), it can handle massive volumes of data millions of messages per second more efficiently than Redis in many large-scale scenarios.
Redis is faster for immediate message delivery (latency) because it runs in RAM. Kafka is optimized for handling massive amounts of data reliably (throughput/durability). The claim is true for latency but misleading if applied to overall processing power or data safety.The claim focuses on a single metric (latency) while ignoring others (throughput, durability). If you are measuring speed strictly by latency the time it takes for a single message to travel from producer to consumer then yes, Redis is generally faster.
The Verdict:
Choose Redis if you need the lowest possible latency and can tolerate potential data loss (or have
a small dataset).
Choose Kafka if you need high throughput, strict data durability, and the ability to replay history.