Month: February 2024

Designing RESTful APIs is an art that requires attention to detail, a deep understanding of HTTP, and a commitment to the principles laid out by Roy Fielding. However, many APIs that claim to be RESTful fall short of these principles. In this blog, let’s explore 20 common mistakes and their remedies :

1. Misuse of HTTP Methods

• Non-RESTful: POST /getSubscription?id=123
• RESTful Remedy: GET /subscriptions/123

2. Ignoring Caching Opportunities

• Non-RESTful: Responses without Cache-Control.
• RESTful Remedy: Include Cache-Control: max-age=3600 in GET responses for subscriptions.

3. Inconsistent Error Handling

• Non-RESTful: {"error": "It failed"}
• RESTful Remedy: {"error": {"code": 404, "message": "Subscription not found"}} with a 404 status code.

4. Lack of Resource Nesting

• Non-RESTful: /subscriptions, /users
• RESTful Remedy: /users/123/subscriptions to list subscriptions for user 123.

5. Overuse of Query Parameters

• Non-RESTful: /subscriptions?userId=123
• RESTful Remedy: /users/123/subscriptions

6. Forgetting Pagination

• Non-RESTful: Returning all subscriptions in one call.
• RESTful Remedy: /subscriptions?page=1&limit=10

7. Failing to Version the API

• Non-RESTful: Directly modifying the API structure.
• RESTful Remedy: /v2/subscriptions/123

8. Underutilizing HTTP Headers

• Non-RESTful: Passing API keys as query parameters.
• RESTful Remedy: Authorization: Bearer <token>

9. Not Supporting Conditional Requests

• Non-RESTful: Ignoring use of ETag or Last-Modified.
• RESTful Remedy: Respond with ETag header and honor If-None-Match requests.

10. Poor Resource Identification

• Non-RESTful: Ambiguous identifiers.
• RESTful Remedy: /subscriptions/{uuid} where uuid is a unique identifier.

11. Ignoring Idempotency in Non-GET Requests

• Non-RESTful: POST /subscriptions/123/renew leading to multiple renewals.
• RESTful Remedy: PUT /subscriptions/123/renewal to renew idempotently.

12. Not Leveraging HATEOAS

• Non-RESTful: { "subscriptionId": "123", "status": "active" }
• RESTful Remedy:

{ "subscriptionId": "123", "status": "active", "_links": { "self": { "href": "/subscriptions/123" }, "cancel": { "href": "/subscriptions/123/cancel" } } }

13. Mixing Singular and Plural Nouns

• Non-RESTful: Inconsistent use of singular and plural in resource paths.
• RESTful Remedy: Consistently use plural nouns for resource names: /subscriptions for collection routes and /subscriptions/{id} for specific entities.

14. Exposing Internal Implementation Details

• Non-RESTful: Revealing database IDs or internal structure through APIs.
• RESTful Remedy: Use abstracted, meaningful identifiers: /subscriptions/12345 where 12345 is an opaque identifier.

15. Not Providing Filtering, Sorting, or Searching Capabilities

• Non-RESTful: Forcing clients to download entire data sets.
• RESTful Remedy: Implement query parameters for server-side operations: /subscriptions?status=active&sortBy=startDate

16. Lack of Media Type Negotiation

• Non-RESTful: Only supporting application/json.
• RESTful Remedy: Use the Accept header for format requests. Respond to Accept: application/xml for XML format.

17. Incomplete or Missing Documentation

• Non-RESTful: APIs without comprehensive documentation.
• RESTful Remedy: Provide detailed, up-to-date documentation portal.

18. Not Utilizing PATCH for Partial Updates

• Non-RESTful: Using PUT for all updates.
• RESTful Remedy: Implement PATCH for partial resource updates.

19. Treating Collections and Individual Resources the Same

• Non-RESTful: Same endpoint for collection and individual resource operations.
• RESTful Remedy: Differentiate endpoints for collections and individual resources: POST /subscriptions for creating and GET /subscriptions/123 for fetching.

20. Not Handling Asynchronous Operations Properly

• Non-RESTful: Expecting synchronous completion of long-running tasks.
• RESTful Remedy: Use asynchronous patterns with initial 202 Accepted responses: POST /subscriptions/123/renew returns 202 Accepted with a Location header for status checks.