How to Design RESTful API URL Structures

REST URL Design Principles

REST URLs should represent resources (nouns), not actions (verbs). Use plural nouns for collections, nested resources for relationships, and query parameters for filtering and pagination.

Resource Naming Conventions

Use lowercase with hyphens for multi-word resources: /api/v1/user-profiles/ not /api/v1/UserProfiles/. Keep URLs shallow — avoid nesting beyond two levels. /users/123/orders/456 is fine; /users/123/orders/456/items/789/reviews is too deep. Create a top-level /reviews endpoint instead.

Versioning Strategies

URL path versioning (/api/v1/, /api/v2/) is the most explicit and visible approach. Header versioning (Accept: application/vnd.api.v2+json) keeps URLs clean but is harder to test and debug. Query parameter versioning (?version=2) is simple but can conflict with caching.

Filtering and Pagination

Use query parameters for filtering: /products?category=electronics&min_price=100. For pagination, cursor-based pagination (using an opaque token) is more reliable than offset-based pagination for large datasets. Include next and previous links in your response for easy navigation.

Common Mistakes

Avoid verbs in URLs — use HTTP methods instead: POST /orders/ not POST /create-order. Don't return different resource types from the same endpoint. Don't use query parameters for resource identification (/users?id=123 should be /users/123). Always use HTTPS — API URLs should never work over plain HTTP.