API Developer interview questions

REST API, or Representational State Transfer API, is an architectural style for designing networked applications. It uses standard HTTP methods which makes it a popular choice for web services due to its simplicity and scalability, allowing systems to communicate over the web easily.

GET method is used to retrieve data from a server, while POST is used to send data to a server to create/update a resource. GET requests can be cached and remain in the browser history, while POST requests do not.

API Rate Limiting is a technique for controlling the rate at which a client can make requests to an API. It is necessary to prevent abuse, ensure fair usage of resources, and protect server backends from being overwhelmed.

API security can be ensured through various methods such as using API keys, OAuth tokens, HTTPS for encrypted communication, rate limiting, and regular security audits.

Common HTTP status codes include 200 (OK), 201 (Created), 400 (Bad Request), 401 (Unauthorized), 403 (Forbidden), 404 (Not Found), and 500 (Internal Server Error).

CORS, or Cross-Origin Resource Sharing, is a security feature implemented in web browsers to allow or restrict requested resources on a web server depending on where the HTTP request was initiated. It is important for client-side security to prevent unauthorized access to resources.

API versioning is a way to manage changes and updates to an API without disrupting existing client applications. It can be implemented using approaches such as URL path versioning, query parameters, custom headers, or content negotiation.

Swagger is a tool used for documenting APIs. It provides an interactive API documentation and allows developers to test API endpoints directly from the documentation. Swagger helps in ensuring the API documentation is consistent and up-to-date.

Errors in an API can be handled by returning appropriate HTTP status codes, providing meaningful error messages, logging the errors for debugging, and possibly using error reporting services to get notified about errors.

API gateways manage request routing, composition, and protocol translation, focusing on providing a unified entry point for clients. Service meshes, however, provide a dedicated infrastructure layer for managing service-to-service communication within a distributed application, often handling microservices networking and security aspects.