Best Practices for Designing Consistent Backend APIs

Effective API design starts with resource‑oriented principles: treat entities as resources, collections as groups, and use URLs to identify them, e.g., /users for a collection and /users/{userId} for a single item.

Use kebab‑case for URL paths ( /system-orders) and camelCase for query and body parameters ( orderId), ensuring consistency and readability.

Represent collections with plural nouns and avoid using raw table names; prefer domain‑specific terms like /product-orders instead of product_order.

Keep verbs out of resource URLs; rely on HTTP methods (GET, POST, PUT, PATCH, DELETE) to express actions, reserving verbs only for non‑CRUD operations such as POST /alarm/{id}/resend.

Include standard endpoints for monitoring: /health (200 OK), /version (service version), and /metrics (performance data), and consider /debug or /status for additional diagnostics.

Version APIs using simple numeric prefixes (e.g., /v1/shops/3/products) placed at the leftmost part of the path to minimize breaking changes.

Return the total number of resources in list responses using a total field, and always accept limit and offset parameters for pagination (e.g., GET /shops?offset=5&limit=5).

Allow callers to request specific fields via a fields query parameter to reduce payload size, such as GET /shops?fields=id,name,address,contact.

Never place authentication tokens in URLs; transmit them in headers, e.g., Authorization: Bearer xxxx, and enforce short‑lived tokens.

Validate the Content-Type header (e.g., application/json) and reject unsupported types to prevent misuse.

Apply the correct HTTP method for each CRUD operation: GET for retrieval, POST for creation, PUT for full updates, PATCH for partial updates, DELETE for removal.

When modeling nested resources, reflect relationships in the path, such as GET /shops/2/products or DELETE /shops/2/products/31.

Enable CORS for public APIs, allowing origins with * while securing access with OAuth tokens.

Handle errors with appropriate 4xx status codes and return detailed validation messages when multiple issues exist.

Follow the “golden rules”: prefer flat over nested structures, keep designs simple, use strings over numbers for identifiers, and prioritize consistency over custom solutions.