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API (Application Programming Interface)

By Fleur Sykes

Updated: May 3rd, 2023

Reviewed by: Simon Cast

Fact checked by: Megan Saker

What is an API?

An API (Application Programming Interface) is a set of protocols, routines, and tools for building software and applications. It enables different software applications to communicate with each other and exchange data. APIs are used in all operating systems, including Windows, Linux, and macOS.

An API is made up of several components that work together to enable communication and data exchange between software applications. Here are the key components:

  1. API Specification: This defines the functionality, including the available resources, methods, parameters, and data formats. It provides a clear description of how it works and how it can be used.
  2. API Gateway: This acts as an entry point, routing requests to the appropriate backend services and handling security, authentication, and rate limiting. It helps to ensure that it can scale efficiently and is secure.
  3. API Calls: These are the requests and responses exchanged between the client application and the API. API calls typically use a specific protocol, such as HTTP or WebSocket, and a defined data format, such as JSON or XML.
  4. API Developer Portal: This is a web interface that provides documentation, tools, and resources for developers to learn about the API, test it, and integrate it into their applications. The portal can also include community forums, support, and analytics to help developers optimize their use of it.
  5. API Development Tools: These are software tools used by developers to build and test APIs, such as code editors, API testing frameworks, and mock servers. These tools can help ensure that the API functions as expected and meets the required quality standards.
  6. API Data Formats: These are the formats used to exchange data between the client application and the API. Some common formats include JSON, XML, CSV, and Protobuf. The data format used depends on the design and the requirements of the client application.

By working together, these components enable software applications to communicate with each other, exchange data, and integrate functionality seamlessly.

What are the types of APIs?

There are different types of APIs, including:

  1. Remote APIs: These are APIs that allow developers to interact with a remote system or service.
  2. Internal APIs: These are APIs that are used within an organization and are not intended to be used by external developers.
  3. Public APIs: These are APIs that are made available to external developers, usually for free or for a fee.

What are the API Programming Languages:

APIs can be written in almost any programming language that is capable of handling network requests and responses. Some of the most common programming languages used to develop APIs include:

  1. Java: Java is a popular choice for building enterprise-level APIs because of its scalability, performance, and robustness. Many popular APIs, such as the Amazon Web Services (AWS) API, are built using Java.
  2. Python: Python is a versatile programming language that is easy to learn and use, making it a popular choice for building APIs. Many popular APIs, such as the Google Maps API, are built using Python.
  3. Ruby: Ruby is a dynamic, object-oriented programming language that is known for its simplicity and productivity. Many popular APIs, such as the Twitter API, are built using Ruby.
  4. PHP: PHP is a server-side scripting language that is widely used for web development. It is a popular choice for building APIs that power web applications and e-commerce platforms.
  5. JavaScript: JavaScript is a client-side scripting language that can also be used to build APIs. With the rise of Node.js, JavaScript is now used to build server-side APIs as well.

Other programming languages used to build APIs include C#, Go, Swift, and Kotlin, among others. The choice of programming language depends on various factors such as the API’s purpose, the development team’s expertise, the performance requirements, and the infrastructure used to host it.

What are the most common API formats?


REST APIs are a popular choice for many web applications because they are lightweight, scalable, and easy to implement. REST APIs use standard HTTP methods like GET, POST, PUT, and DELETE to access and manipulate resources. Data is typically exchanged in JSON or XML format.

Some well-known REST APIs include:

  1. Twitter: Allows developers to access Twitter data and integrate Twitter functionality into their applications.
  2. Facebook Graph: Enables developers to access Facebook user data and build Facebook-related applications.
  3. GitHub: Provides developers with access to GitHub data, such as repositories, users, and issues.


SOAP APIs are a bit more complex than REST APIs and are typically used in enterprise-level applications. They use a standardized XML format to transmit data and require more overhead than REST APIs. SOAP APIs define the structure of messages, which makes them more reliable and secure.

Some well-known SOAP APIs include:

  1. eBay: Allows developers to access eBay data and build eBay-related applications.
  2. Amazon Web Services (AWS): Enables developers to interact with AWS services, such as Amazon S3 and Amazon EC2.
  3. Salesforce: Provides developers with access to Salesforce data and allows them to build custom applications that interact with Salesforce.

To use an API, developers typically need to register for an API key or access token from the provider. This key or token is used to authenticate and authorize requests to the API. Once the developer has the key or token, they can make API calls to retrieve data or perform actions, depending on the API’s functionality. The provider usually provides documentation on how to use the API, including example requests and responses.

What is Microservices Architecture and how does it work?

Microservices architecture is a software design approach that breaks down an application into smaller, independent services, each with its own API. This approach allows for each service to be developed and deployed independently, which can make the overall system more scalable, resilient, and easier to maintain. Microservices communicate with each other using lightweight protocols such as HTTP, and they can be deployed on different servers or even in different data centers.

What are Remote Procedure Calls (RPC) and how does it work?

Remote Procedure Calls (RPC) is a protocol that enables developers to call methods or functions on a remote system as if they were local. RPC works by allowing a client application to send a request to a server application, which then executes the requested procedure and returns the results to the client. This approach allows developers to build distributed systems where different services can communicate with each other across different machines or even across the internet.

What is a Web API and how does it work?

A Web API is designed to be accessed over the internet using HTTP. Web APIs are typically designed to provide access to specific functionality or data, such as weather data, financial data, or social media data. Web APIs can be accessed using a variety of programming languages and platforms, and they are often used by developers to build web applications, mobile applications, and other software products.

What are software components and how are APIs used in their development?

Software components are individual parts of a larger software system, each with its own specific functionality. APIs are often used as building blocks for larger software components or applications. For example, a payment processing system might use APIs from multiple providers to handle credit card processing, fraud detection, and bank transfers. By leveraging existing APIs, developers can save time and resources while building more complex systems.

How do APIs enable software applications to exchange data?

APIs enable different software applications to exchange data by providing a standardized interface for communication. By using APIs, developers can ensure that different systems can understand and interpret data in a consistent way, making it easier to share and combine data from different sources. APIs can also be used to define and enforce security and access controls, ensuring that data is exchanged securely and only with authorized parties.

How to manage APIs?

Managing APIs involves designing, documenting, publishing, securing, and monitoring them. Here are some key aspects of API management:

  1. API Design: Define the functionality, its endpoints, data formats, and security requirements.
  2. API Documentation: Create clear and concise documentation that describes how to use it.
  3. API Publication: Publish it in a centralized location to make it easily accessible to developers.
  4. API Security: Implement authentication and authorization mechanisms to protect it from unauthorized access.
  5. API Monitoring: Monitor the usage, performance, and availability to ensure it meets the required service level agreements (SLAs).

An example of an API

One example of an API is Google Maps, which provides developers with access to Google Maps data, including maps, geocoding, and routing information. By integrating the Google Maps API into their applications, developers can add location-based functionality, such as finding nearby restaurants or displaying driving directions.


Who manages an API?

APIs can be managed by different stakeholders, depending on the organization’s structure and goals. Some common management roles include:

  1. API Product Manager: Responsible for defining the API’s functionality, target audience, and monetization strategy.
  2. API Developer: Responsible for building and maintaining the API’s infrastructure and functionality.
  3. API Operations Engineer: Responsible for ensuring the API’s availability, performance, and security.
  4. API Business Analyst: Responsible for analyzing the API’s usage, performance, and revenue.

How can product managers use an API?

Product managers can use APIs in various ways to create more value for their products and customers. Here are some examples:

  1. Integrate third-party APIs into the product to add new features and functionality.
  2. Create APIs for the product to enable integration with other applications and services.
  3. Monitor API usage to gain insights into how customers are using the product and identify opportunities for improvement.
  4. Develop a monetization strategy for the application program interface, such as charging a fee for access to premium features or data.

How do APIs fit into product management?

APIs play a critical role in product management, enabling products to integrate with other applications and services and creating new opportunities for revenue generation. By understanding the different types of APIs and how to manage them effectively, product managers can develop products that are more powerful, flexible, and valuable to customers. Additionally, product managers can leverage APIs to gain insights into customer behavior and usage patterns, which can inform future product development and roadmap planning.

If you’re interested in how the ProdPad API works please click here

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