Testing Enivroment

By Admin · 1/21/2026

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Testing Enivroment

System Design: How to Think Like a Backend Engineer

System design is not just about drawing boxes and arrows. It’s about making trade-offs, understanding scale, and designing systems that are reliable, maintainable, and cost-effective.

This blog walks through how to approach system design, especially for interviews and real-world applications.

1. What is System Design?

System design is the process of defining:

  • Architecture

  • Components

  • Data flow

  • Communication patterns

The goal is to build a system that can:

  • Handle expected traffic

  • Scale when needed

  • Fail gracefully

[[image:https://images.unsplash.com/photo-1555949963-aa79dcee981c]]

2. High-Level vs Low-Level Design

High-Level Design (HLD)

Focuses on:

  • Services

  • Databases

  • APIs

  • Load balancers

Example questions:

  • How many users?

  • Read-heavy or write-heavy?

  • Latency requirements?

Low-Level Design (LLD)

Focuses on:

  • Classes

  • Data structures

  • APIs

  • Database schemas

Both are important, but interviews usually start with HLD.

3. Core System Design Components

Load Balancer

Distributes incoming traffic across multiple servers to avoid overload.

Common choices:

  • NGINX

  • AWS ALB / ELB

[[image:https://images.unsplash.com/photo-1581092919535-7146c1b3bb3d]]

Application Servers

These handle business logic and API requests.

Key considerations:

  • Stateless vs Stateful

  • Horizontal scaling

  • Caching at the application layer

Database

Choosing the right database is critical.

Use CaseDatabase
Relational dataPostgreSQL
High write throughputMongoDB
Fast accessRedis

[[image:https://images.unsplash.com/photo-1544383835-bda2bc66a55d]]

4. Caching Strategy

Caching improves performance and reduces database load.

Common caching layers:

  • CDN (Cloudflare)

  • Redis

  • In-memory cache

Cache patterns:

  • Cache-aside

  • Write-through

  • Write-back

5. Scalability: Vertical vs Horizontal

Vertical Scaling

  • Add more CPU/RAM

  • Simple but limited

Horizontal Scaling

  • Add more machines

  • Requires stateless services

  • More complex but scalable

Rule of thumb: design for horizontal scaling early.

[[image:https://images.unsplash.com/photo-1518770660439-4636190af475]]

6. Handling Failures

Failures are inevitable.

Good systems:

  • Use retries with backoff

  • Have circuit breakers

  • Monitor health metrics

Key tools:

  • Prometheus

  • Grafana

  • Sentry

7. System Design Interview Mindset

Interviewers care more about how you think than the final answer.

Always:

  1. Clarify requirements

  2. Define constraints

  3. Start with a simple design

  4. Improve step-by-step

Avoid jumping straight into databases or frameworks.

8. Final Thoughts

System design is a skill that improves with:

  • Practice

  • Reading real architectures

  • Building scalable side projects

Start small, break things, learn, and iterate.

If you can explain why you made a choice, you’re already ahead of most candidates.

References & Inspiration

  • Designing Data-Intensive Applications

  • System Design Primer

  • Real-world architectures (Netflix, Uber, Twitter)

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