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API Definition

API definition

APIs are ubiquitous and are often in use without you realizing it. Several times a day, everyone accesses different APIs, facilitating, for example, a login process, a data retrieval, or a data transfer. 

But what is behind such an API? We have defined APIs and analyzed the different types for you.


APIs are necessary to learn programming, and understanding them will expand the scope of development. For beginners, the concept of API is a little difficult to understand. That's why we start with the easy stuff - Wikipedia

“An application programming interface (API) is an interface that defines interactions between multiple software applications or mixed hardware-software intermediaries.”


This is still a bit difficult to understand, so to explain it more simply, an API is a software intermediary that allows two applications to talk to each other. Let us take an example:

Imagine you are sitting at a table in a restaurant with a menu to choose from. The kitchen is the part of the "system" that prepares your order. What is missing is the crucial link to transmit your order to the kitchen and deliver your food back to your table. This is where the waiter or API comes in. The waiter is the messenger - the API - who takes your request or order and tells the kitchen - the system - what to do. Then the waiter delivers the answer back to you; in this case, it's the food.

What an API Also Provides Is a Layer of Security

Your phone’s data is never fully exposed to the server, and likewise the server is never fully exposed to your phone. Instead, each communicates with small packets of data, sharing only that which is necessary - like ordering take out. You tell the restaurant what you would like to eat, they tell you what they need in return and then, in the end, you get your meal.

API program

APIs have become so valuable that they account for a large part of many companies' revenues. Large companies like Google, eBay,, Amazon, and Expedia are just a few of the companies that make money from their APIs. The "API economy" refers to this marketplace of APIs.

The Modern API

Over the years, an "API" has often included any kind of generic Connection interface described to an application. More recently, however, the modern API has taken on some characteristics that make it extremely valuable and useful:

Modern APIs adhere to standards (typically HTTP and REST) that are developer-friendly, easily accessible and generally understandable.

They are treated more like products than code. They are designed for use by specific target groups (e.g. mobile developers), they are documented, and they are versioned so that users can have certain expectations about their maintenance and lifecycle. Because they are much more standardized, they have much more discipline for security and governance, and monitoring and management for performance and scale.

What are some types of API used?

There are 3 types of APIs used commonly today:

  • Open API - Open APIs are publicly available for anyone to use.
  • Partner-API - Partner APIs are designed by companies to offer API access to strategic business partners as an extra revenue channel for both parties. For example, Ticketmaster offers a Partner API to allow its clients the ability to reserve, buy, and retrieve ticket/event information.
Barcode scanner
  • Private API- Private APIs are not designed for public use and are designed for internal use. Let’s say you are travelling to a different city for a business meeting. You need to make a quick trip to the bank. You walk into “ABC Bank” and give the teller your account number. She quickly pulls up your account and you make a withdrawal. The teller was able to pull up your information by using ABC’s internal system, which uses an API to pull your account information and to update your new account balance.

Advantages of using APIs for developers:

  1. Automation: with APIs, computers rather than people can manage the work. Through APIs, agencies can update workflows to make them quicker and more productive.

  2. Application: because APIs can access the app components, the delivery of services and information is more flexible.

  3. More scope: with an API an application layer can be created which can be used to distribute information and services to new audiences which can be personalized to create custom user experiences.

  4. New data available: an API allows all the information generated at the government level to be available to every citizen, not just a select few.

  5. Efficiency: When access to a API is enabled, the generated content can be published automatically and is available for each channel. This makes them easier to share and distribute.

  6. Integration: APIs allow content to be embedded from any site or application more easily. This guarantees more fluid information delivery and an integrated user experience.

  7. Personalization: through APIs any user or company can customize the content and services that they use the most.

  8. Adaptation: Needs change over time and APIs help anticipate changes. When working with this technology, data migration is better supported and information is more accurately verified. In a nutshell: APIs make service delivery more flexible.

Conclusion - Key Learnings

It’s important to remember key takeaways for APIs are as follows:

  • APIs are prevailing tools that are used to fast-track your business.
  • APIs make connections and product shopping possible at a rapid speed such as booking a hotel or ordering a movie ticket.
  • APIs provide key insights into real-time possibilities for analytics delivery on the spot.
  • APIs give the developer The ability to make an API call or "request" to obtain information.


APIs are an essential part of software design and they exist at every level of the software stack. They provide a way to define and manage abstractions by telling us what we can do with software components and how we can do it. Well designed APIs support efficient, fluid, and effortless deployment and use, while poorly designed APIs tend to cause headaches every time they are used.

Need to link two different systems via an API?

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