For Juniors and Frontend Developers: Usable and Maintainable API Design

Title may be confusing but if you are a Frontend developer who is curious about API development, this article will be so helpful to you.

I have worked with many APIs during my career. Some of them were 3rd party APIs, and some were our own projects. For Frontend Developers, working with a poorly-structured API can sometimes be painful. If you want to build an API, you must ensure its usability. That’s why I want to share my experience and knowledge stored in Apple Notes with you.

---

If these titles caught your attention, you likely already know what an API is. Their main role is enabling different software systems to communicate with each other. But why is their structure so important?

---

1. Usability & Maintainability

Because we’re human beings. Both usable and maintainable API design is crucial for ensuring team members understand the logic easily and work efficiently. This is the key to long-term success and scalability for growing projects.

Today’s Plan: Usability

Usability in API design refers to how easily developers can understand and use the API. It is totally about the actual usage. While planning a strategy it will be related to the efforts that need to be done ASAP.

A usable API should have:

• Clear Documentation: Comprehensive and easy-to-understand docs.
• Consistency: Consistent naming conventions and structures.
• Intuitive Design: Logical and predictable behavior.
• Error Handling: Clear and helpful error messages.

Being Ready for the Future: Maintainability

Maintainability is how easily the API can be updated and extended over time without causing issues for existing users. A maintainable API should have:

• Versioning: Strategies to manage changes and updates.
• Modularity: Separation of concerns and reusable components.
• Backward Compatibility: Ensuring new changes do not break existing functionality.
• Testing: Comprehensive test coverage to ensure reliability.

---

2. Best Practices for Usable APIs

I think examples from real life would be more helpful than theories. Let’s give some:

a. Clear and Consistent Naming Conventions

Adopting clear and consistent naming conventions helps users understand the API without extensive documentation.

Follow industry standards and conventions, such as using nouns for resources (e.g., /users, /orders) and HTTP verbs for actions (GET, POST, PUT, DELETE).

No need to use getAllUsers or getUserById etc. Keep it simple as it can be.

/users /users/123

These 2 base URLs are enough for most calls. Actions (GET, POST, PUT, PATCH, DELETE) do the remaining work.

What if there is a relation with another collection? If we want to list all users from a company:

/companies/1234/users

This helps developers understand the logic behind the API.

📚 Book Advice: Web API Design: Crafting Interfaces that Developers Love (Brian Mulloy)

---

b. Comprehensive Documentation

Documentation is essential for usability. Tools like Swagger (my choice) or Postman Collections can help you create interactive and user-friendly docs.

Good documentation must include:

• Overview: General info about the API and its purpose.
• Endpoints: Parameters, request/response examples, error codes.
• Authentication: How to authenticate requests.
• Examples: Practical examples and use cases.

---

c. Consistent and Predictable Behavior

Design the API to behave consistently across all endpoints.

• Always return the same response structure for similar operations.
• Use standard HTTP status codes.

This predictability reduces the learning curve.

---

d. Thoughtful Error Handling

Provide meaningful error messages and codes:

• Avoid generic 500 Internal Server Error without context.
• Use descriptive messages with helpful info (error type, details, possible solutions).

---

e. API Versioning

If you’re working for a startup, there’s a big chance of API updates. Implement versioning to avoid breaking existing users.

Common approaches:

• URI Versioning: /v1/users
• Header Versioning: Accept: application/vnd.api.v1+json

---

3. Best Practices for Maintainable APIs

a. Modularity and Separation of Concerns

Design the API with modularity in mind.
Break down functionality into smaller, reusable components.

I really like and appreciate the service-oriented structure.

---

b. Automated Tests

Implement automated testing for all aspects of the API:

• Unit tests
• Integration tests
• End-to-end tests

This ensures changes don’t introduce bugs.

---

c. Backward Compatibility

Ensure new updates don’t break existing functionality.

• Use versioning.
• Provide clear deprecation policies.
• Communicate changes to users.
• Give them time to migrate. (Demo meetings help a lot!)

---

d. Scalability and Performance

Design the API to handle increasing loads.

• Optimize database queries.
• Use caching (example: Redis).
• Apply rate limiting to prevent abuse.

📌 Example: A Node server with Redis cache + MongoDB.

• Checks Redis first.
• If cache miss → fetch from MongoDB → store in Redis → return response.
• Rate limiter blocks abuse usage.

👉 Learn more on AWS: Boosting MySQL Database Performance with ElastiCache for Redis

---

e. Security

Security is critical in API design.

• Use strong authentication & authorization.
• Use HTTPS for all traffic.
• Validate inputs to prevent injection attacks.

⚠️ Security is a big topic — I’ll cover it in a dedicated article.

---

Closing

Hope you found this article useful!

Investing time and effort into designing high-quality APIs will pay off by:

• Reducing support & maintenance costs
• Increasing developer satisfaction
• Enabling your platform to scale effectively

Warm Regards!