You know that moment when you push your code to production, lean back, and wait for Slack to explode?

Yeah... that was me last year, all thanks to a tiny misconfigured Kafka topic.

Long story short:

Messages were flying everywhere except where they needed to go. Consumers were confused, partitions were misaligned, and I spent my Saturday night debugging with the comforting glow of system logs.

If you're working with Kafka and Spring Boot, this story is for you.

Let's talk about the hard-earned lessons that textbooks won't teach you. 💬

🔧 Lesson 1: Topics Are Not "Set and Forget"

When creating Kafka topics, I used to think:

"It’s just a name and some partitions, right? What could go wrong?"

(Answer: Everything.)

Quick Tips:

  • Always define replication factor wisely. No one likes losing messages because a single broker took a nap.
  • Pre-create topics where possible. Auto-creation sounds cool until it isn't configured properly and your app fails silently.
  • Naming matters — clear, consistent naming saves you (and your team) headaches six months later.

⚙️ Lesson 2: Tune Your Consumer Settings Early

Kafka consumers are like hungry toddlers:

If you don't feed (configure) them properly, expect tantrums (outages).

Quick Tips:

  • Set a reasonable max.poll.records — too high = memory issues, too low = bad throughput.
  • Handle retries carefully. Infinite retries sound safe until you end up with a never-ending zombie message.
  • Monitor lag aggressively. Lag today is downtime tomorrow.

🔒 Lesson 3: Don't Ignore Error Handling

The first time our consumer threw an exception, guess what we did?

Logged it... and moved on. 🙃

(Meanwhile, thousands of broken messages piled up in the background.)

Quick Tips:

  • Use a Dead Letter Topic (DLT) strategy — not optional, mandatory.
  • Implement custom error handlers to gracefully process (or skip) bad messages.
  • Alert on failures — not just when services die, but when patterns of failure emerge.

🧹 Lesson 4: Clean Up After Yourself

Old topics don't die; they linger... and cause confusion, increase storage costs, and attract blame during incidents.

Quick Tips:

  • Set retention.ms appropriately for each topic.
  • Periodically audit and delete unused topics.
  • Create naming conventions that make deprecation obvious (*_deprecated, anyone?).

💬 Real Talk: What Separates Juniors from Seniors?

Juniors set up Kafka topics and celebrate when the consumer reads a message.

Seniors know that production-readiness is about what happens when things go wrong.

Handling failures, monitoring lag, preparing for scaling, documenting quirks — that’s the real backend craftsmanship.

I'd love to hear from you! 🎤

  • Have you had your own Kafka horror story?
  • What’s the smallest mistake that caused the biggest chaos in your system?

👉 Drop your war stories or tips in the comments. Let’s help each other build better, more resilient systems. 🚀