1. Producer

• Sends records (messages) to Kafka
• Chooses:
  • Topic
  • Partition (explicitly or via key hashing)
• Can send:
  • Fire-and-forget
  • Synchronous
  • Asynchronous (with callback)

Producer → Topic → Partition

2. Topic

• Logical channel
• Data is not updated or deleted (only compacted or expired)

order-events
payment-events
user-login-events

3. Partition

• Like subdivision of topic
• Allows parallel processing and scalability.
• Each partition is an ordered log
• Messages in a partition are ordered by offset

Topic: order-events
  ├──Partition0 (offset 0, 1, 2 …)
  ├──Partition1

⚠️ Ordering is guaranteed only within a partition