Building a RESTful API with Node.js and PostgreSQL

An API (application programming interface) is a set of rules and protocols that allow one application to communicate with another. Think of it as a messenger that takes the request, tells the system what we want, and then returns the response. For example, when we use a weather app, the app sends a request to a weather API, which retrieves the weather data and sends it back to the app.

In the context of web development, APIs are typically used to enable communication between the client (e.g., a web browser or mobile app) and the server (e.g., the Node.js application). 

However, as applications grow more complex, so does the need for a structured and efficient way to design APIs. If every developer created APIs with different conventions, integrating different systems would be chaotic. Imagine every website having its own unique way of fetching user data—some using custom request formats, others requiring complex authentication in every call, and none following a standard approach. This inconsistency would make it difficult for developers to build reliable, scalable, and maintainable applications.

To address this challenge, REST (Representational State Transfer) provides a set of guiding principles for designing APIs in a standardized way. By following these principles, RESTful APIs make it easier for different systems to communicate predictably and efficiently over the web.

What is a RESTful API?

A RESTful API is an API designed following REST principles, ensuring consistency and simplicity in how web services communicate.

• Client-server architecture: Separates concerns between the client (UI/front-end) and the server (data storage/back-end), allowing them to evolve independently.

• Statelessness: Each request is independent, carrying all the information the server needs to process it.

• Cacheability: Responses can be explicitly marked as cacheable to improve performance by reducing redundant requests.

• Uniform interface: Consistent use of HTTP methods (GET, POST, PUTPUT is an HTTP method, used to update or replace an existing resource entirely., PATCHPATCH is an HTTP method used to partially update an existing resource by modifying specified fields., DELETEDELETE is an HTTP method that is used to remove resources.) to represent actions on resources, with resource representations typically formatted in JSON or XML for interoperability.

• Layered system: Allows for multiple intermediary layers (e.g., load balancersLoad balancers distribute incoming network traffic across multiple servers to optimize performance, reliability, and prevent overload., security layers ...