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What is an Application Programming Interface (API)?

by Iwan Price-Evans on DevOps • May 13, 2022

An application programming interface (API) is a set of rules that allows programs to talk to each other. APIs allow programmers to easily move data or trigger actions between applications.

An API is a collection of functions, procedures, variables, data structures, etc., that allow programs to interact with each other. It provides a standard interface between two or more applications.

Why Do We Need APIs?

APIs are essential for developers because they make it easier to build software and to integrate their software with third-party applications or operating systems. For example, iOS developers can use the iPhone's APIs to access Apple Pay for payments or the Share Sheet for content sharing. 

APIs are essential for DevOps and other operational teams that need to manage data flows and automation between multiple platforms and applications. For example, APIs make it easy to map data between web analytics platforms, CRM platforms, and e-commerce platforms, keeping everything synchronized.

Developers can also choose to add an open API to their own platform or application, enabling other developers to integrate their own services with it.

How To Create A Simple API

APIs are often used to provide access to data stored in databases. They also enable users to perform actions such as sending emails or making phone calls. APIs are usually written using an object-oriented programming language, such as Java, C#, PHP, Python, Ruby, or JavaScript.

How To Secure An API

APIs are vulnerable to threats, malicious users, and malfunctioning services that integrate with them.

The most critical API security risks surround the access controls to expose valuable data. APIs, by their nature, expose valuable data including sensitive information such as Personally Identifiable Information (PII). 

Application Logic could also be exposed unintentionally and create vulnerability vectors in your organization. Unauthorized or excessive access can result in data disclosure to unauthorized parties and access to malicious actors' data exploitation, data manipulation, or complete account takeover.

The OWASP API Security Project lists the Top 10 API Security vulnerabilities, including:

  • Broken Object Level Authorization
  • Broken User Authentication
  • Excessive Data Exposure
  • Lack of Resources & Rate Limiting

You can secure an API and enforce access control, service level agreements (SLA), and Quality of Service (QoS) using an API Gateway.