Application Programming Interface

What is an API?

A set of rules and protocols that allows different software applications to communicate and interact with each other.

This will give you a basic understanding

This will give you a detailed understanding

Different Types of API Styles

Name	What is it?	What is it in simple terms?
REST (Representational State Transfer)	An API style that uses standard HTTP methods (GET, POST, etc.) to interact with resources, represented as URLs.	Like ordering from a restaurant menu: you ask for what you need (via URL), and it gets delivered.
SOAP (Simple Object Access Protocol)	A protocol that uses XML to send structured data and follows strict rules for communication.	Like sending a formal letter with strict guidelines for format and content.
GraphQL	A query language for APIs that allows clients to request only the data they need in a single query.	Like choosing exactly which toppings and portions you want on a pizza.
gRPC (Google Remote Procedure Call)	A high-performance API style that uses binary data (Protocol Buffers) for faster communication, supporting streaming.	Like making a direct phone call instead of exchanging letters for faster communication.
WebSockets	A protocol for real-time, two-way communication between client and server over a single connection.	Like having a live, open conversation where both can talk at the same time.
RPC (Remote Procedure Call)	An API style where a client executes a function on a remote server as if it were local.	Like asking someone else to bake a cake for you, and they follow your exact recipe.
JSON-RPC	A lightweight version of RPC that uses JSON for data exchange.	Like sending a simple text message with instructions to get a task done.
XML-RPC	An older version of RPC that uses XML for data exchange.	Like sending a structured email to get a task done.

JSON

JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is widely used in APIs, configuration files, and data exchange between systems.

Key Features of JSON:

Human-Readable: JSON is structured in a way that is easy to understand at a glance.
Lightweight: It uses minimal syntax, reducing the overhead of data exchange.
Language-Independent: Though derived from JavaScript, JSON can be used in most programming languages (Python, Java, C#, etc.).
Self-Describing: JSON clearly defines its data structures.

What is REST API?

REST API: Key Concepts, Best Practices, and Benefits | Altex

Rest API Request Structure

HTTP Method

The method specifies the type of action the client wants to perform. Common HTTP methods include:
- GET: Retrieve data from the server.
- POST: Send data to the server to create a resource.
- PUT: Update or replace an existing resource.
- PATCH: Partially update an existing resource.
- DELETE: Remove a resource.
EndPoint

The endpoint is the URL where the API is hosted, pointing to a specific resource.

Used to provide additional information or specify particular details that the server needs to process the request correctly and return the desired result.
- Query Parameters: Added to the URL after a ? symbol and separated by &.
- Path Variable: Typically used to identify a specific resource by ID or name.
Header

Headers provide additional information about the request, such as:
- Authorization: Contains credentials like API keys or tokens to authenticate the client (e.g., Authorization: Bearer <token>).
- Content-Type: Indicates the format of the data being sent (e.g., application/json for JSON data).
- Accept: Specifies the format of the data the client expects in the response (e.g., Accept: application/json).
Payload/Data

The body contains data sent to the server, usually with POST, PUT, or PATCH requests. It is often formatted in JSON, XML, or other data formats.