System design is fundamentally about making the right trade-offs that balance competing priorities such as simplicity, scalability, performance, and complexity. This guide thoroughly explores key architectural trade-offs to help build resilient, scalable, and efficient systems.

YouTube video: https://youtu.be/2g1G8Jr88xU?si=jaXr9njh_UUjsD-C

1. Vertical Scaling vs. Horizontal Scaling

Vertical Scaling (Scaling Up)

• Definition: Increasing resources on existing servers, e.g., adding more CPU, memory, or upgrading hardware.
• Advantages:
  • No code changes required.
  • Easier management and simplicity.
• Disadvantages:
  • Eventually hits a physical limit.
  • Hardware upgrades can be expensive.
• Use Case: Suitable for early-stage or smaller-scale applications with moderate load.

Horizontal Scaling (Scaling Out)

• Definition: Adding more servers to distribute application load.
• Advantages:
  • Virtually unlimited scaling potential.
  • Improves fault tolerance by spreading load.
• Disadvantages:
  • Introduces complexity with load balancing.
  • Requires handling data consistency and distributed system challenges.
  • Needs more engineering effort.
• Use Case: Large-scale applications needing growth beyond vertical limits.

Summary:

Key Insight: The trade-off here is simplicity vs. scalability. Choose vertical scaling early on, then move to horizontal as growth requires.

2. REST APIs vs. GraphQL APIs

REST APIs