What Is an API?

If you’re searching for technology-forward solutions to your business’s everyday needs, you’ll hear a lot of talk about APIs. But what is an API, and how does it factor into the operations of a modernized organization?

In this guide, we’ll define APIs and explore how they work, the various application programming interfaces available, and the business benefits you can unlock by integrating APIs.

Defining APIs

An application programming interface (API) is a piece of code that facilitates communication between two programs. It includes a set of rules dictating how the applications should request information from one another, structure responses to information queries, and transmit data.

Think of an API as an intermediary that expands the functionality of existing applications by streamlining the flow of information between systems, business partners, or internal departments.

How does an API work?

Without APIs, each new software solution must know how existing programs are implemented to share information and communicate. This isn’t necessary with APIs; the application programming interface acts as a translator.

Imagine you only speak English and need to communicate with someone who only speaks French. Without an intermediary, one of you would have to learn the other’s language. But if you have a translator, they could relay the information and help you compose an appropriate response to each statement or question. APIs work in a similar way. 

APIs contain two key elements: a software interface and a set of rules. Developers publish the interface to the two applications they’re trying to connect. The applications then use the interface to communicate with one another.

The rule set governs how the apps communicate and respond to one another. If application A sends a query request structure in a specific way, application B will use the rules to create the appropriate response.

Although APIs make it far easier to connect two applications, they aren’t a plug-and-play solution — you must conduct extensive API testing to ensure it functions as intended. Through testing, you can identify any deficiencies in the flow of information and remedy them before they negatively impact end users.

Types of APIs

Most application programming interfaces are web APIs, which expose an application’s functionality and data over the internet. These are the most common types of web APIs:

• Open APIs: An open API or public API is an open-source solution anyone can access with an HTTP protocol. They rely on request and response formats and have clearly defined endpoints.
• Partner APIs: Business partners rely on partner APIs to connect their applications and streamline the flow of information. Developers typically access partner APIs via a public developer portal but must obtain login credentials first.
• Internal APIs: Also known as private APIs, developers hide these APIs from external users. Businesses use them to improve productivity and collaboration between internal teams and departments.
• Composite APIs: Composite APIs combine multiple APIs, allowing programmers to solicit information from numerous sources to perform a single, complex task.

Most organizations rely on a combination of partner, internal, and composite APIs, but there are some instances where you may also use open APIs. For example, open APIs can connect your website’s customer-facing features to back-end applications or databases.

API benefits

By implementing APIs, you can accomplish the following:

• Securely manage how systems access service functionality and data
• Provide third parties, such as trading partners, access to your digital resources
• Expand your customer base
• Enhance productivity
• Increase data transparency and eliminate silos

These are just a few of the many benefits associated with APIs. Application programming interfaces can also extend the life of applications and reduce your development costs while providing much-needed functionality. 

API challenges

Of course, there are certain limitations and challenges associated with using APIs, including the following:

• API implementation can be costly and complex.
• APIs require frequent updates to ensure proper function.
• You must thoroughly test APIs to ensure they perform as designed.
• APIs may be vulnerable to cyberattacks due to their standardized nature.

Despite these concerns, APIs represent the most pragmatic method for connecting applications and streamlining data-sharing across your organization. 

API protocols

Developers categorize APIs by type or the protocols they use. The following API protocols are most prevalent:

• REST: REST, or RESTful APIs, rely on standard HTTP commands and are ideal for transferring data via the internet.
• SOAP: SOAP APIs use XML to transfer highly structured messages between servers and clients. Although many legacy systems use SOAP, newer, cloud-based solutions largely depend on nimbler protocols, like REST.
• GraphQL: This open-source query language allows clients to communicate with a single API endpoint without stringing together multiple requests and provides excellent reliability, primarily when used on networks with slower connections.
• Webhooks: Webhooks send automated requests when an event-based trigger occurs, such as when a customer makes a payment. The webhook will automatically send relevant event data and then take appropriate action.
• gRPC: Originated by Google, the gRPC API has protocols that allow clients to call on a server like a local object, simplifying communication between distributed systems and applications.

Of these, SOAP and REST APIs are the most common. There are several critical differences to keep in mind when comparing SOAP versus REST APIs, including the following:

• REST APIs are based on a set of flexible guidelines and are more lightweight, making them the ideal pairing for IoT devices, mobile apps, and serverless computing.
• SOAP APIs have more specific requirements, such as mandatory usage of XML messaging. 

The most notable distinction is that the REST architecture allows providers to deliver data in several formats, including the XML language mentioned above and HTML, YAML, and JSON. JSON is particularly effective for data-sharing applications because it’s object-based.  

APIs vs. web services

Regarding web services versus APIs, the primary distinction relates to the type of communication they facilitate. Web services enable machine communication, whereas APIs allow apps to communicate and exchange data.

Additionally, web services require a network connection and often rely on XML or SOAP, which aren’t as popular as they once were. Conversely, APIs may or may not require a network to maintain operability. APIs that use RESTful protocols provide much greater flexibility than traditional web services. REST APIs can be used with JSON, YAML, and HTML.  

SOAs vs. microservices

Service-oriented architectures (SOAs) and microservices are two architectural frameworks that use remote APIs.

SOAs are the older architecture and were designed to replace monolithic applications. Developers use SOAs to expand the functionality of a central application using several complementary apps, each coupled to the primary app using an enterprise service bus (ESB).

The downside is that developers may inadvertently disrupt the performance of one application by altering or replacing another app within the SOA. 

Like SOAs, microservices use loosely coupled services and apps. However, microservices rely on modern frameworks like RESTful APIs. This simplifies communication between related applications and promotes modularity, meaning developers can replace or enhance one service without negatively affecting other services within the architecture.

Connect critical business systems with modern APIs

APIs are invaluable tools for connecting your mission-critical business systems. You can also use modern cloud-based systems like Orderful to simplify EDI integration and streamline communications with your trading partners. Orderful combines the proven principles of EDI with modern APIs to promote efficiency and transparency.

To learn more about Orderful and how our platform can support the continued growth of your business, contact us and speak to an implementation expert today.