An API is a set of defined rules that explain how computers or applications communicate with each other. These sit between an application and the web server, acting as an intermediate layer that processes data transfers between systems. APIs are something like the communication language of machines .
These programming interfaces simplify software development and innovation . How do they do this? By allowing applications to exchange data in a simple but, above all, secure manner.
What is an API for?
An application programming interface allows companies to open their data and application functionality to third-party developers, business partners, and internal departments within their companies.
This allows services and products to communicate with each other and leverage data through a documented interface.
Developers don’t need to know how to implement an API; they just need to know how to use that interface to communicate with other products. That way, they can work to grow the company as a whole.
The use of APIs has increased over the past decade to the point that many of today’s most popular web applications are based on this protocol.
Types of API
APIs have had to evolve to meet the needs of most IT developments. These are the types of APIs you should be familiar with:
- Open: These are open-source application programming interfaces that can be accessed using the HTTP protocol. They are also known as public interfaces. They have defined endpoints, as well as request and response formats.
- Partner-based: These are application programming interfaces (APIs) provided by strategic business partners. Typically, developers can access these interfaces self-service through a public developer portal.
- Internal: These are application programming interfaces that remain hidden from external users. Since they are private, they are not available to users outside the company and, instead, are intended to improve productivity and communication between the various internal development teams.
- Composite: Combines multiple data sources or services. These services allow developers to access multiple endpoints in a single call. Composite services are useful in microservices architectures, where performing a single task may require information from multiple sources.
Examples of how APIs work
Below we show you some API examples to give you a practical understanding of how they work. Don’t miss out!
- A client application initiates an API call to retrieve information (also known as a request).
- This request is processed from an application to the web server via the Uniform Resource Identifier (URI) and includes a request verb, headers, and sometimes a request body.
- After receiving a valid request, the function makes a call to the external program or web server.
- The server then sends a response with the requested information.
- Finally, the API transfers the data to the initial requesting application.
While the data transfer will differ depending on the web service used, this process of requests and responses is done through an API . While a user interface is designed to be used by humans, APIs are designed to be used by a computer or application.
Another example would be:
- Consider an API offered by a payment processing service.
- Customers can enter their card details into an e-commerce store’s app interface.
- The payment processor does not require access to the user’s bank account.
- The API creates a unique token for this transaction and includes it in the server call.
- This ensures a higher level of security against potential hacking threats.
Advantages of the API
Whether you’re managing existing tools or designing new ones, you can use an application programming interface to simplify the process.
In short, some of the main benefits of APIs are the following:
- Improved collaboration: Large companies use an average of nearly 1,200 cloud applications (the link resides outside of IBM), many of which are disconnected. These applications enable integration so that these platforms and applications can communicate seamlessly with each other. Without them, many companies would lack connectivity and suffer from information silos that compromise productivity and performance.
- Easier innovation: They offer flexibility, allowing businesses to connect with new business partners and offer new services to the current market. And ultimately, access new markets that can generate massive returns and drive digital transformation. For example, Stripe started as an API with just seven lines of code. Since then, the company has partnered with many of the world’s largest companies.
- Data monetization: Many companies choose to offer data for free, at least to build a developer audience. When AccuWeather (the link is outside of IBM) launched its self-service developer portal to sell a wide range of API packages, it took only 10 months to attract 24,000 developers. And from that point on, the developments are generating revenue!
- Security has been added: Developers can further strengthen API security by using tokens, as well as signatures and Transport Layer Security (TLS) encryption. This feature is enabled by implementing gateways to authenticate traffic through effective management.
What is REST API?
A fundamental concept in this topic is the REST API. What is it? REST stands for Representational State Transfer. A REST API works by decomposing an activity . This generates a sequence of smaller components , each of which addresses a specific part of the activity.
It is a way for two computer systems to communicate via HTTP, similar to web browsers and servers.
Flexibility is assigned from this component, but challenges can certainly arise:
- REST APIs use standard HTTP procedures. They use GET to retrieve a resource, or PUT to change the API’s state or update a resource.
- All API calls are stateless. This means that the RESTful service cannot retain anything between implementations.
