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Web Services Vs. API | How do They Compare Regarding Their Use

All web services are APIs, but are all APIs web services? Should you use the two terms interchangeably?

Both web services and APIs help in data transfer between various applications on the internet. Although the two tech terms overlap, they don't refer to the same concepts.

Suppose you are looking for the distinction between web services Vs. API, we've got you covered. We'll look at the features that differentiate the two and the pros and cons of each.

Distinction Between Web Services Vs. APIs

A significant distinction between an API and a web service is that a web service is a type of API but not all APIs are web services.

A web service works by sharing files with other applications, making it an API, while an API is broader as it's an intermediary between two disconnected applications.

What Is a Web Service?

A web service is a resource that's available on the internet. It communicates through a network, which is mostly the internet.

It refers to open protocols used to exchange data between various applications and patterns.

Web services are implemented in two major ways, including:

  • REST: the REST webs service works with various components, including media files and objects that work using a specific hardware device. A web service with REST principles can be referred to as RESTful. It works with other components using HTTP protocol verbs such as DELETE, post, GET and PUT.

  • SOAP: according to the SOAP messaging protocol, the web service supports XML data shared via HTTP requests. The SOAP messaging protocol is more secure and preserves data integrity better than APIs. However, REST is more strict than REST as it's more process-intensive and code-heavy.Web services are also associated with Service Oriented Architecture (SOA). The SOA architectural pattern is used for making applications with features that are divided and can be used as services in a network.

devices and services graphic icons

Features of Web Services

  • A web service can be invoked, located, and published across the web. It uses the existing structure. The web service requester uses lightweight Internet Standards, including HTTP, to invoke the service provider.

  • They are self-contained. As a client, you don't require any additional software. XML and HTTP programming languages are enough to get you started. A SOAP and HTTP server is enough on the server-side.

  • Web services are self-describing. With the Web Service Description Language (WSDL), you'll have all the information you require for implementing the service as a provider.

  • They offer programmatic access. They operate at the code level with no graphical user interface.


  • A web service facilitates interaction between various software applications.
  • Web services support remote procedure calls.
  • They help you exchange data between various web applications and platforms
  • You can use them as a web page request and enable you to receive data
  • They offer different applications as a way of linking their data


  • The services may require specialized machines to implement
  • The HTTP protocol is unreliable, and you have no guarantee of delivery

What Is an API?

API stands for Application Programming Interface. The Application Programming Interface allows two web applications to interact without user intervention.

It's a set of procedures and functions that allow you to build on the application and data of another existing web application. It comprises standard rules that determine the type of data to be modified from an application.

An API utilizes data integration. The interface enables you to request data from another application. Most of the integrations on the internet are due to Application Programming Interface.

The interfaces that send data over the internet are known as web APIs. Examples of APIs include:

  • Pay with PayPal
  • Google Maps
  • Weather snippers
  • Twitter Bots
cubes with icons

You can think of an API as a waiter. When you visit an eatery, you order food, and the waiter brings the food to you. However, the waiter isn't the one who has prepared the food. They take your order, take it to the kitchen and bring you the food. The waiter is the intermediary.

In the same way, an API acts as an intermediary that fosters a connection between different technologies for an enhanced user experience. For example, when you get paid using PayPal, the app itself doesn't generate the money. The API connects your payment source and the platform where you access your payment.

Software developers use various architectures in building an API, including Simple Object Access Protocol (SOAP) and Representational State Transfer (REST).

What Is an API Used for?

An API helps to access data of a particular software and works to ensure its compatibility with the interacting software.

An end-user may not have an interaction with an API. However, they benefit from it when their request is fulfilled. As such, APIs are interfaces, but they're not applications. At the back of an API is a lot of coding that powers the internal structures that make it possible to access any software.

Features of a Web API

  • It offers JSON Support/ REST. An API won't be considered good only if it's RESTful. However, most APIs are RESTful and support JSON. Since REST APIs are stateless, they are an excellent choice for applications that require a lot of messaging, such as mobile apps.
  • Authorization via OAuth. It's an open standard for authorization that offers better usability.
  • Good documentation. API documentation should be written with the user in mind who has no clue or knowledge about the API. Therefore, it should include lots of examples.
  • A great API should also include modification timestamps and search by criteria. It should allow you to look for particular data using particular criteria such as by date.
  • APIs are also customizable and language-independent.
  • They also offer a wider reach for the users


  • APIs help you to expose data to your browser
  • They are also based on HTTP protocol, which is easy to define
  • It supports traditional create Read Update Delete (CRUD) as it uses HTTP verbs GET, PUT, POST, and DELETE
  • It enables customization and personalization
  • APIs are time effective


  • Creating an API is a demanding and time-consuming process
  • They have a high maintenance cost

Is REST API a Web Service?

Yes, a REST API is a web service. It is a standardized architecture style that software developers use in developing a web service API.

One requirement for a REST API is using the HTTP protocol when making a request over the web.

A client's REST request from a client has various components that include:

  • URL path
  • HTTP method
  • Header
  • Parameters
  • Body

What Is the Difference Between an API and a Web Service?

Both APIs and web services facilitate data transfer over various applications on the web. Although the two are similar, they're not identical.

The most significant distinction between the two is that web services are a type of API. On the other hand, not all APIs are web services.

data transfer illustration

So how do the two tech terms differ?

Web Services Have Limited Access

One difference between an API and web service applications is that web services offer limited accessibility. The web services owners can control the users to access their data, functions, and also how they use the web services.

On the other hand, some APIs can allow any developer to use them.


Web services mostly stick to the SOAP design as it preserves data integrity better than APIs and is also more secure.

On the other hand, an API can employ a variety of architectural designs, including SOAP, REST, JSON-RPC, and XML-RPC.

Web services usually encode their data using the XML format. Alternatively, APIs mostly use any language to store data. APIs use the JavaScript Object Notation (JSON) language to store their data as it's a lightweight option.


Another differentiating factor between an API and a web service is that the latter is a network-based resource. As such, it requires a network connection to communicate. Usually, network communications happen through the internet.

On the other hand, APIs are no network-based resources. APIs can use networks, such as the internet, in their operation. However, they can also function offline.

You can have two apps on the same device integrating using an API. Communication happens between the two apps, but there's no network involved.

a person using cellphone and laptop


APIs and web services are valuable technologies for transferring data between various software applications. Although they are similar, the two tech terms are not identical and may not be used interchangeably. An API is an interface that enables you to communicate data from a software application to outside software. On the other hand, a web service is a type of API with stricter requirements, and it needs a network to communicate data with other apps. Having a clear distinction between the two will help you better understand your product integrations.

About Dusan Stanar

I'm the founder of VSS Monitoring. I have been both writing and working in technology in a number of roles for dozens of years and wanted to bring my experience online to make it publicly available. Visit https://www.vssmonitoring.com/about-us/ to read more about myself and the rest of the team.

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