Differences between Web Services and Web API

Both web services and APIs are vital to modern software architecture, but developers need to remember that while these terms have some overlap, they are fundamentally not the same. We’re going to help you understand what distinguishes a web service vs. API since they have different uses depending on the needs of your software.

What is an API?

An application programming interface (or API for short) is a software component that enables two otherwise unrelated applications to communicate with each other. The result of this communication is increased functionality. An API consists of standardized rules and functions that determine what data may be taken or modified within an application and how the process occurs.

APIs enable software integrations since they expose some of an application’s inner data that developers use. This makes an API an “interface” — you can request data from an otherwise closed-off application. Remember: it’s not uncommon for organizations to use several APIs.

While some APIs are open (free and publicly available), others are private. In other words, some are only accessible by approved developers — and likely have a price tag attached. Alternatively, a company may create internal APIs to connect its systems, such as in a micro service.

Thanks to today’s API economy, these components are behind most integrations we see over the internet. Web APIs are software components that send data over the internet. As an example, think about your weather apps. Your weather app isn’t generating the data itself — it’s simply requesting this information from a weather API. From there, the weather API will connect software that gathers and stores the data with the application on your phone that tells you it’s going to rain tomorrow (sorry).

There are several architectures software developers follow to create an API, but the most popular is Representational State Transfer (REST) or Simple Object Access Protocol (SOAP). These have some differences but have a shared central goal. API architectures standardize APIs, ensuring they can communicate using standard languages and procedures.

What is a web service?

A web service is a resource that is available over the internet. It’s valuable because it provides functionality other applications can use, such as payment processing, logins, and database storage. This collection of protocols and standards is typically used to exchange data between apps or systems.

Web services “provide a standard means of interoperating between different software applications, running on a variety of platforms and/or frameworks. Web services are characterized by their great interoperability and extensibility, as well as their machine-processable descriptions thanks to the use of XML. They can be combined in a loosely coupled way in order to achieve complex operations.”

Because web services enable software applications to work in tandem (even when built in disparate ways), utilizing different web services can help a developer combine many functions without having to code them all. The result is saving time, energy, and money in-house.

If you’re familiar with Service Orientated Architecture (SOA), you’re likely aware of how vital web services are. SOA divides the software’s function applications into modular services connected over a network. Then, SOA enables the reuse of the same function across multiple applications. The best part? There will be no need to re-code anything.

Keep in mind, however, that web services require a network to interact, and this networked communication is usually achieved thanks to SOAP. SOAP encodes data in XML, a common markup language for storing and transferring information, and sends it via HTTP, which is the same protocol that delivers web pages from web servers to browsers. An application sends an XML request to the service and replies with a response formatted in XML.

Web services can also follow REST principles — but SOAP is more common.

Though APIs and web services can both facilitate data transfers between applications over the internet, they are not the same, and the terms should not be used interchangeably in every case. The key distinction is that web services are a type of API: All web services are APIs, but not all APIs are web services.

Both APIs and web services are technologies that enable the transfer of data between separate software applications. API is an interface that exposes an application’s data to outside software, whereas web applications are one type of API with stricter requirements. These requirements include network communication, SOAP as the primary protocol, and less accessibility for the public.

While these definitions might seem quite nuanced, it’s essential to comprehend the subtle but important distinctions between web technologies. Armed with this knowledge, you’ll be well-equipped for discussions with developers and better understand your product’s integrations.