What is an APi?
Tags: programming, api, softwareengineering, developer
Published: 2023-07-26 08:43:57

**What you need to know about API.**

Envision installing a weather application that provides you with daily weather forecasts. Once you tap on the app, it retrieves the specific weather details you seek. The app acquires the data it displays by making requests to an Application Programming Interface (API), which in turn communicates to another software that considers the date, time, and location before returning the relevant results.
An API functions as a medium for computer programs to interact and exchange data amongst themselves. It employs a predefined structure to facilitate data sharing and retrieval. APIs play a vital role in contemporary technology by supplying software applications with necessary data and promptly delivering it when required.

Here's a comprehensive overview of APIs:

● **Purpose of APIs**:

   The role of an API is to act as a bridge between two or more computer programs that then share data endlessly.
The achievement of this functionality is enabled by employing a pre-established framework that streamlines the processes of data sharing and retrieval, ensuring efficiency.
![Purpose of APIs](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/5a7rvhj1yhngifvrlpiw.png)

● **Types of APIs**:

   - **Web APIs (RESTful APIs)**: These are APIs that use the HTTP protocol to pass information or data and are widely used over the internet. They use a principle known as Representational State Transfer (REST), making them simple, scalable, and stateless. RESTful APIs make use of standard HTTP methods, including GET, POST, PUT, and DELETE, to carry out various operations on resources.
![Web API](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/j2t8feecbs56la4tyonk.jpeg)

   - **SOAP APIs**: Simple Object Access Protocol (SOAP) APIs use a message format known as XML and can use various transport protocols like HTTP, SMTP, TCP, etc. They were in great use in the past, but RESTful APIs have become the next big thing due to their pattern of being simple.
![Soap API](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/g2izg3038aalftpqipc2.png)

   - **GraphQL APIs**: GraphQL is an alternative to REST APIs. This type of API limits the number of calls or requests an end-user or client can make and in turn, improves efficiency.
![Graph API](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/hwqcz0rxptc4665i2a95.jpeg)

● **API Endpoints**:

   An API usually consists of various endpoints, each having a distinct function or resource that is accessible through a distinct URL. To illustrate, a weather API could offer endpoints built for providing current weather conditions, forecasts, and historical data.

![Example of API endpoint](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/0qjg51seylrkp2lvhly7.png)

● **Authentication and Authorization**:

   APIs frequently necessitate authentication to ensure that specific resources are only accessible to authorized users or applications. Common methods of authentication encompass API keys, OAuth tokens, and JSON Web Tokens (JWT), which help ensure the security and controlled access of API resources to avoid unnecessary and unwanted users.

![API authentication](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/4mmssdd73vwwzapu5f2w.png)

● **API Documentation**:

   Comprehensive API documentation is crucial for developers to grasp the effective utilization of the API. This documentation typically composes information about accessible endpoints, request parameters, response formats, error handling, and usage examples, all of which aid developers in using the API appropriately.

![Example of documentation](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3axzgwsn3p8lesrogxkz.jpeg)

● **Rate Limiting**:

   A significant number of APIs implement rate limits to regulate the number of requests a client can make within a specific period. Rate limiting serves the purpose of preventing misuse and promoting equitable usage among all consumers of the API.

![Rate Limiting in process](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/u2sf0wpc35f5ymx3rq0f.jpeg)

● **Versioning**:

   In the dynamic evolution of APIs, incorporating versioning becomes crucial to preserve backward compatibility. With versioning, developers can specify the particular API version they intend to make use of, guaranteeing that their app works when the APIs are updated or changed.

![Image showing different versions](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/jz0qfnrpavku3ojdrxq6.jpeg)


● **API Clients and SDKs**:

To break down API integration, developers commonly develop API clients or Software Development Kits (SDKs) built for various programming languages. These libraries abstract the complexities of HTTP communication, offering developers a more user-friendly interface to communicate with the API.

![Image showing ask platforms](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/t9cvwc61yeoh2fp9xrsb.jpeg)


● **Use Cases of APIs**:

APIs can be of use to applications in diverse scenarios, including:
- Incorporating third-party services into applications, like payment gateways and social media platforms.
- Developing mobile apps that interact with server-side services.
- Making internal system functionalities accessible for external use by another or more applications.
- Facilitating communication between Internet of Things (IoT) devices and cloud services.

![Use case of API](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/2schyu2s59zxgyty3at0.png)

● **API Security**:

Ensuring API security is essential to safeguard sensitive data and prevent unauthorized access. Employing techniques such as encryption, output encoding, input validation, and secure authentication mechanisms becomes compulsory to guarantee the security of API endpoints.

![API security](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/cj43j8fs3q33m9bzolbf.png)


In essence, APIs serve as foundational elements in contemporary software development, promoting cooperation, integration, and creativity across diverse platforms and services.

**Credit**: All images used were extracted from Google.