๐—ฆ๐˜๐—ฟ๐—ฒ๐—ฎ๐—บ๐—ถ๐—ป๐—ด - sequential movements, processed in real-time.
๐—ค๐˜‚๐—ฒ๐˜‚๐—ถ๐—ป๐—ด - stored in a queue, processed sequentially.

Choosing between streaming and queuing isnโ€™t just about picking Kafka over RabbitMQ. Itโ€™s about making an architectural decision that will define how your system scales, evolves, and handles data over time.

Streaming vs Queuing

Pick the wrong one, and youโ€™ll feel the consequences for years.

๐—ช๐—ต๐—ฒ๐—ป ๐—ง๐—ผ ๐—–๐—ต๐—ผ๐—ผ๐˜€๐—ฒ ๐—ฆ๐—ง๐—ฅ๐—˜๐—”๐— ๐—œ๐—ก๐—š:

  • You need historical data replay (e.g., debugging or analytics).
  • Your system requires event order guarantees (e.g., processing transactions sequentially).
  • Multiple consumers need to read the same event independently.
  • Youโ€™re handling high-throughput data flows that need efficient processing.

๐—ช๐—ต๐—ฒ๐—ป ๐—ง๐—ผ ๐—–๐—ต๐—ผ๐—ผ๐˜€๐—ฒ ๐—ค๐—จ๐—˜๐—จ๐—œ๐—ก๐—š:

  • You need guaranteed task completion (e.g., order processing or background jobs).
  • Each task must be processed by only one consumer (e.g., no need for data replay).
  • The message should be consumed once and discarded after processing.
  • Built-in retries and dead-letter queues offer automatic failure handling.

๐—–๐—ผ๐—บ๐—ฏ๐—ถ๐—ป๐—ฒ ๐—•๐—ผ๐˜๐—ต: ๐— ๐—ผ๐˜€๐˜ ๐—ฆ๐˜‚๐—ฐ๐—ฐ๐—ฒ๐˜€๐˜€๐—ณ๐˜‚๐—น ๐—”๐—ฟ๐—ฐ๐—ต๐—ถ๐˜๐—ฒ๐—ฐ๐˜๐˜‚๐—ฟ๐—ฒ๐˜€ ๐——๐—ผ
The most powerful systems leverage bothโ€”streaming for real-time processing and queuing for task completion. An example might be:

  • Real-time tracking systems (using streaming for events like user activity or sensor data).

  • Task-based systems (using queuing to ensure reliable processing, such as background jobs or transactional workflows).

๐—ž๐—ฒ๐˜† ๐—ฅ๐—ฒ๐—ฎ๐˜€๐—ผ๐—ป๐˜€ ๐—ณ๐—ผ๐—ฟ ๐— ๐—ถ๐˜€๐˜‚๐˜€๐—ฒ
โ†’ Events โ‰  Tasks โ€“ Queues handle tasks (e.g., payments), while streams handle continuous data (e.g., market prices).

โ†’ Latency Matters โ€“ Queues add delays; streams process in real-time.

โ†’ No Replay โ€“ Queues discard messages; streams allow reprocessing.

โ†’Tooling Bias โ€“ Teams stick to familiar queues instead of streaming solutions like Kafka or Pulsar.

This awesome diagram by @boyney123