The Backend Design Patterns We Use Across Most Projects

July 12, 2025

When you build backends for dozens of startups, patterns emerge—not just in code, but in what actually works at scale, under pressure, and with small teams.

At TLVTech, we’ve refined a set of backend design patterns we use across most projects—regardless of stack, industry, or company size. These patterns help us deliver faster, onboard developers quickly, and avoid messy rewrites later on.

Here’s what we use, and why it works.

1. Service-Oriented, Not Microservice-Obsessed

We don’t start with microservices. We start with a modular monolith.

Why:

  • Simpler to test, deploy, and debug
  • Easier to onboard new devs
  • Less infrastructure overhead

Once there’s real scale or organizational need, we extract services with clear boundaries. Premature microservices = wasted time and complexity.

2. Controller-Service-Repository Structure

We keep backend layers clean and predictable:

  • Controller handles requests
  • Service owns business logic
  • Repository interfaces with the database

Why:

  • Easy to test each part independently
  • Reduces coupling between layers
  • Helps junior devs understand flow quickly

This structure works across NestJS, Express, Django, Spring—doesn’t matter. Clean separation always wins.

3. DTOs for Data Contracts

We use Data Transfer Objects (DTOs) to define inputs and outputs between layers.

Why:

  • Avoids leaky abstractions
  • Makes validation and API docs more consistent
  • Reduces bugs from changing internal models

Especially useful in TypeScript and Python with tools like class-validator or Pydantic.

4. Event-Driven Where It Matters

We use async event patterns (pub/sub or message queues) selectively—mainly for:

  • Email/SMS notifications
  • Billing events
  • Background processing

Why:

  • Keeps user-facing flows fast
  • Decouples services over time
  • Improves scalability without breaking the system

We prefer lightweight solutions like Redis streams or AWS SNS/SQS before going full Kafka.

5. Centralized Error Handling & Logging

Every project has:

  • Unified error classes
  • Structured logs
  • A shared logging utility with context-aware tracing

Why:

  • Makes debugging faster
  • Keeps logs readable and searchable
  • Reduces finger-pointing in incident reviews

Observability starts with consistent logging.

6. Configuration Over Convention

We don’t rely on magic. We centralize config using .env files, secrets managers, or config services—so nothing is hardcoded.

Why:

  • Makes deployments safer
  • Enables per-env overrides
  • Easier to rotate secrets and update behavior dynamically

Final Thoughts: Consistency Beats Cleverness

Backend systems don’t win because they’re clever. They win because they’re predictable, understandable, and built to grow.

The design patterns we use are boring on purpose—because boring is what makes products stable, scalable, and easy to maintain.

If you’re building something and want backend that won’t crumble under growth, let’s talk.

July 12, 2025

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