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Alex Aslam
Alex Aslam

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Microservices in Node.js: When They Help (and When They Hurt)

#webdev #programming #javascript #beginners

The Microservices Trap

A year ago, our team made a bold decision: "Let’s break our Node.js monolith into microservices!"

Fast-forward six months, and we were drowning in:

  • 50+ API endpoints calling each other unpredictably
  • Debugging nightmares ("Which service failed?")
  • A 10x increase in AWS costs

We learned the hard way that microservices aren’t always the answer. Here’s when they shine—and when they backfire.

1. When Microservices Help

✅ Scenario 1: Scaling Specific Features

Problem: Our /recommendations API needed 10x more CPU than the rest of the app.
Solution: Isolated it into its own service, scaled independently.

// Before: Part of monolith
app.get('/recommendations', heavyMLProcessing);

// After: Dedicated microservice
fastify.get('/', heavyMLProcessing); // Scaled to 20 pods
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Result: 80% cheaper than scaling the entire monolith.

✅ Scenario 2: Polyglot Tech Stacks

Problem: Real-time analytics needed Go’s performance.
Solution: Built a Go service for analytics, kept the rest in Node.js.

✅ Scenario 3: Team Autonomy

Problem: 10+ devs blocking each other on merges.
Solution: Split ownership by domain (payments, auth, etc.).

2. When Microservices Hurt

❌ Scenario 1: Over-Engineering

Mistake: Splitting a 5K LOC monolith into 10 services.
Pain:

  • Network latency between services
  • Distributed tracing became essential
  • Kubernetes complexity exploded

Lesson: Don’t microservice just because.

❌ Scenario 2: Poor Boundaries

Mistake: Letting services call each other directly.

// 😱 Tight coupling
await fetch('http://payments/api/charge');
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Fix: Use an event bus (Kafka, NATS) for async communication.

❌ Scenario 3: Observability Debt

Mistake: No centralized logging/metrics.
Pain: Debugging required checking 5 different dashboards.
Fix: Adopted OpenTelemetry + Grafana.

3. The Hybrid Approach: Modular Monoliths

For many apps, modular monoliths offer the best balance:

  • Single codebase, but clean separation of domains
  • Optional split later (if needed) 
src/
  ├── modules/
  │   ├── payments/ (Could become a microservice)
  │   ├── auth/     (Could become a microservice)
  │   └── orders/   (Could become a microservice)
  └── server.js     (Shared entry point)
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When to choose this:
✔ Team size < 10
✔ Traffic < 10K RPS
✔ You might need microservices later

Key Takeaways

🔹 Do use microservices for:

  • Independent scaling
  • Polyglot stacks
  • Team autonomy

🔹 Avoid them for:

  • Small teams/apps
  • Tightly coupled features
  • Without observability tools

🔹 Consider modular monoliths as a middle ground.

Have you been burned by microservices? Share your story!

Top comments (2)

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dotallio profile image
Dotallio •

This nails it - the debugging pain is so real and never obvious until it's too late for most teams.
Did you end up missing anything from the monolith days after going hybrid?

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alex_aslam profile image
Alex Aslam •

Great question! We did miss a few things from the monolith days, mainly unified logging and simpler deploys. Tracing requests across services added overhead, and coordinating database migrations became trickier. That said, the scalability gains made it worth the tradeoff.

Curious have you tried a hybrid approach? What was your experience?