How do you use HTTP methods, status codes, and headers to follow RESTful API conventions and best practices?

1 HTTP methods

HTTP methods are the verbs that indicate the action that the client wants to perform on a resource on the server. The most common methods are GET, POST, PUT, PATCH, and DELETE, which correspond to the CRUD operations of create, read, update, and delete. Each method has a specific meaning and semantics, and should be used accordingly. For example, GET should be used to retrieve a resource without modifying it, POST should be used to create a new resource, PUT should be used to replace an existing resource, PATCH should be used to apply partial updates to a resource, and DELETE should be used to remove a resource.

2 HTTP status codes

HTTP status codes are the numbers that indicate the result of the request. They are divided into five categories: 1xx for informational responses, 2xx for successful responses, 3xx for redirection responses, 4xx for client error responses, and 5xx for server error responses. Each code has a specific meaning and implication, and should be used consistently and accurately. For example, 200 OK means that the request was successful and the response contains the requested resource, 201 Created means that the request was successful and a new resource was created, 301 Moved Permanently means that the requested resource has been moved to a new location, 400 Bad Request means that the request was invalid or malformed, and 500 Internal Server Error means that the server encountered an unexpected error.

3 HTTP headers

HTTP headers are the key-value pairs that provide additional information about the request or the response. They can be divided into two types: general headers and entity headers. General headers apply to both requests and responses, and include fields such as Date, Connection, and Cache-Control. Entity headers apply to the entity body of the request or the response, and include fields such as Content-Type, Content-Length, and ETag. Headers can be used to convey metadata, negotiate content formats, control caching, validate resources, and implement authentication and authorization.

4 RESTful API conventions

Following the RESTful API conventions, you should use HTTP methods, status codes, and headers in a way that reflects the principles of REST, such as statelessness, uniformity, and resource orientation. Nouns should be used to identify resources and plural forms for collections (e.g. /users, /users/123, /users/123/posts). Query parameters can be used to filter, sort, paginate, or search resources (e.g. /users?name=John&age=25&sort=asc&page=2). HTTP methods should indicate the operation on the resource and the appropriate status codes should indicate the outcome (e.g. GET /users/123 returns 200 OK with the user details). HTTP headers can provide additional information about the request or response (e.g. Content-Type: application/json, Authorization: Bearer token, Cache-Control: no-cache). Finally, HATEOAS can be used to provide links to related resources or actions in the response body (e.g. {"id": 123, "name": "John", "links": [{"rel": "self", "href": "/users/123"}, {"rel": "posts", "href": "/users/123/posts"}]}).

5 RESTful API best practices

To improve the quality, performance, and usability of your RESTful API, you should adhere to some of the best practices that are widely accepted by the API community. For example, you should use HTTPS to secure your API and protect the data in transit. Versioning is also important for managing changes and avoiding breaking existing clients. You should also document your API with tools such as Swagger or Postman, and use authentication and authorization with standards such as OAuth or JWT to control access and permissions. Error handling and logging are also key for handling exceptions and providing meaningful feedback to the client. You should also use testing and monitoring tools such as JMeter or New Relic to ensure the reliability and availability of your API.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?