API (Application Programming Interface)

The Application Programming Interface (API) is a collection of interfaces that enable data exchange and function sharing between software systems. APIs allow developers to establish secure, structured, and standards-compliant connections with different applications or services. Fundamentally, they serve as a bridge enabling one software system to access services provided by another.

Although the concept of API was first introduced in the 1960s, it began to occupy a central position in software engineering during the 2000s, particularly with the proliferation of the internet and the rise of service-oriented architectures. Today, APIs are critical in many technologies including web services, mobile applications, microservices architectures, and the Internet of Things (IoT).

Core Functions of an API

APIs provide protocols and sets of rules that make software components running in the background accessible and manageable from outside. Developers can use APIs to perform activities such as intra-system or inter-system data processing, data querying, and action triggering. The core functions of APIs can be summarized as follows:

• Abstraction: It hides complex business logic and technical details from users, who interact only with the functions they need.

• Standardization: It enables different systems, languages, and platforms to communicate through a common communication protocol, facilitating software integration.

• Reusability: An API defined once can be reused across multiple applications and different projects, accelerating the software development process and reducing costs.

• Secure Access: It ensures data security and access control through authorization mechanisms.

Types of APIs

Based on usage purpose and access level, APIs are categorized into four groups:

1. Public APIs: This is an API type made available to a broad developer community, typically well-documented and freely accessible. Examples include the Google Maps API and the Twitter API.

2. Partner APIs: These are APIs shared selectively with specific business partners or stakeholders, usually requiring a registration and approval process.

3. Private APIs: These are APIs used exclusively within the internal systems of a single organization. They are tightly managed for security and performance reasons.

4. Component APIs: They facilitate data exchange between software components such as modules and services, playing a key role in microservices architectures.

Applications in Daily Life

APIs play critical roles behind the scenes of web and mobile services. Many applications used daily by users interact with various systems through APIs without the user being aware. Examples include:

• Finance and Banking: Mobile banking applications use APIs to display user account information and process payment transactions.

• Social Media: Third-party applications can connect to social media accounts and retrieve user data through APIs.

• Maps and Navigation: Travel and transportation applications process location data using map APIs.

• E-Commerce: Shipping tracking systems, inventory information, and payment processes are integrated through APIs.

API Security and Management

The widespread adoption of APIs has brought associated security risks. To prevent unauthorized access by malicious actors, the following security measures are implemented:

• Authentication: API users are verified using standards such as OAuth 2.0 and JWT (JSON Web Token).

• Access Authorization: Role-based access controls determine which users can access which data.

• Use of API Gateway: An API Gateway manages incoming requests, filters them, and logs activity. It also handles load balancing, rate limiting, and monitoring.

• Data Encryption: Secure communication is ensured during transmission of sensitive data using TLS/SSL protocols.