How to design API for large system?
Ask by Anubhav Sharma
Updated 21 Mar 2026
Designing an API for a large system requires planning, scalability, security, versioning, and maintainability. In interviews, this question checks your system design knowledge, not only coding.
1. Follow RESTful API Design Principles
Use standard HTTP methods.
Example:
2. Use Layered Architecture (Important for Large System)
Large systems should follow:
Example in .NET
Benefits:
3. Use API Versioning (Very Important)
Large systems must support multiple versions.
Example:
In .NET Core:
Why needed?
4. Use Authentication & Authorization
For large systems use:
Example:
Security rules:
5. Use Proper Error Handling
Return standard response.
Good format:
Use:
6. Use Logging & Monitoring
Large systems must track errors.
Use:
Log:
7. Use Pagination for Large Data
Wrong
Correct
Benefits:
8. Use Caching
For large systems caching is required.
Use:
Example:
Cache result.
9. Use Async & Background Processing
For heavy work use:
Example:
10. Use Microservices (For Very Large System)
Instead of one big API:
Benefits:
11. Use API Gateway (Enterprise Level)
Large systems use API Gateway.
Example:
Benefits:
12. Follow Naming Convention
Good:
Bad:
Use nouns not verbs.
13. Performance Optimization
Use: