API vs Web Service: What’s the Difference?

API vs Web Service: What’s the Difference?

The highly competitive environment of today’s business world makes workflow digitalization a must for all businesses. When you leverage technology to optimize your processes, you can get the job done faster, helping you get ahead of your competitors.

Application Programming Interfaces (APIs) and web services are two of the most vital components in digital transformation. While these two tend to overlap, you must know how to distinguish them from one another.

In this article, we’ll explore the key differences between API vs. web service.

Table of Contents

What Is an API?

An API is a set of guidelines that outline how two software systems should communicate with one another. It provides a standardized way for one system to access another platform’s functionalities, features, and data. This can include features such as reading and writing data, performing calculations, or triggering actions.

Aside from standardized communication, here are some common features you’ll find in APIs:

1. Platform independence

APIs are often designed to be platform-agnostic. This means that they can be used to enable communication between systems regardless of their underlying technology or programming language.

2. Authentication and authorization

This technology often include mechanisms for authenticating and authorizing users or applications that want to access the API, including basic authentication, OAuth, or API keys.

3. Documentation

APIs usually come with detailed documentation explaining how to use the API along with examples of common scenarios and use cases. This can include information about the API’s endpoints, input parameters, and output data.

4. Versioning

Versioning mechanisms enable developers to update the API without breaking existing applications that depend on it. This can involve using different URLs or header values to specify the version of the API that an application is using.

5. RESTful architecture

Many web APIs use a RESTful (Representational State Transfer) architecture. RESTful is a set of guidelines used for designing scalable, flexible, and easy-to-use APIs.

API vs Web Service: What’s the Difference?

What Is a Web Service?

A web service is a software system that enables communication and data exchange between different software systems over the internet. It typically uses a combination of standards-based technologies such as XML, SOAP, and HTTP to allow different systems to communicate with each other in a platform-agnostic way.

Some common features of web services include:

1. Data transformation

Web services may include mechanisms for converting data from one format to another. This allows different systems to communicate even if they use different data formats.

2. Data validation

This technology offers features used for ensuring the accuracy and completeness of data being exchanged. This helps to ensure that the data is correct and reliable.

3. Error handling

A web service should be able to handle mistakes and exceptions that may occur during communication between systems. This can include returning error messages or codes to the calling system or logging the error for later analysis.

4. Transactions

It also supports transactions, allowing multiple operations to be grouped together and treated as a single unit of work. This can help ensure that data is consistent and accurate across different systems.

Key Differences Between API and Web Service

At first glance, API and web services appear quite similar to each other. After all, both technologies are used mainly for communication between two platforms. But there are key differences between these two. Let’s take a look at some of them:


One of the major factors that differentiates API from web service is the manner in which they are used. In a business setting, both of them are used in different ways. For example, an organization might use an API to integrate its CRM system with its invoicing system. They can also use it to allow their mobile app to access data from its back-end database.

On the other hand, a web service might allow an e-commerce application to access real-time shipping rates from a shipping company’s system. Businesses can also use it so that their financial application can access real-time quotes from a stock exchange.


APIs are accessed using specific programming instructions, while web services use standardized protocols such as HTTP, XML, and SOAP to enable communication between systems.

For example, an API might be accessed using a programming library or a set of functions provided by the API provider. In contrast, a web service might be accessed using an HTTP request and response.


There’s also a key difference in terms of the systems architecture between API and web services. The former may use a variety of architectural styles, including RESTful, RPC (Remote Procedure Call), or SOAP-based architecture.

In contrast, the latter are typically designed using a RESTful or SOAP-based architecture. For example, a RESTful API might use HTTP methods such as GET, POST, PUT, and DELETE to perform different actions. A SOAP-based web service might use a more complex message-based architecture.

Data format

APIs may return data in a variety of formats, including JSON, XML, or CSV. Web services typically return data in a standard format such as XML or JSON.


APIs are typically accessed through specific programming instructions, while web services are accessed over a network using standardized protocols.

Overall, while APIs and web services both enable communication and integration between different software systems, they differ in terms of their protocols, architecture, data formats, and access methods.

API vs Web Service: What’s the Difference?

The Pros and Cons of Using Web Service vs API

Pros of API

Improved efficiency

APIs can help organizations streamline and automate their processes by allowing different systems to communicate with each other. This can save time and reduce errors by eliminating the need for manual tasks.

Enhanced functionality

This technology allows you to create a more unified system. This means that APIs can provide access to the functionality of other systems. Your organizations can leverage the capabilities of those systems in their own applications.

Greater flexibility

As mentioned earlier, APIs are often designed to be platform-independent, which means you have the ability to connect two different platforms from varying built and designs. This allows organizations to be more flexible and adaptable in their use of technology.

Enhanced security

APIs can include built-in security features such as authentication and authorization, which can help protect against unauthorized access and data breaches.

Cons of API


One of the biggest downsides of using APIs is that it can be complex to implement and maintain. You must have specialized knowledge and resources on this matter. Otherwise, you might have to spend extra on experts to help you integrate.

Dependency on external systems

Organizations that rely on this technology for key functionality may be vulnerable if the external system becomes unavailable or experiences issues. You might also encounter problems if there are any updates or changes in the resources.

Limited or no control

Organizations may have limited control over the functionality and performance of external systems accessed through APIs.

Pros of web services


Web services enable companies to take advantage of existing capability without having to rebuild it by allowing it to be reused across many apps and systems.


This technology is typically designed to be maintainable and support updates and enhancements over time. This can help reduce the long-term maintenance costs of integrating with other systems.


Since web services are often designed to be compatible with a wide range of systems and applications, it makes it easier for you to integrate them into an organization’s existing technology stack.


Web services are extensible, which allows organizations to add new functionality and capabilities as needed.

Cons of web services


Depending on the complexity of the web service, it may require a significant amount of time and resources to integrate it into an organization’s systems.


If an organization relies heavily on a web service, it may be at risk of disruption if the service is unavailable or experiences downtime.

Limited functionality

A web service may not provide access to all of the functionality that an organization needs, requiring the development of additional custom integrations.

Security risks

If a web service is not properly secured, it may be vulnerable to data breaches or unauthorized access.


Web services may not always be as performant as other integration methods, especially for applications with high volumes of traffic.


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By using a fax API, businesses can eliminate the need for expensive hardware and long-distance phone charges, resulting in significant cost savings. This can also help you save time while also improving security and supporting remote work.

When you sign up with iFax, you can integrate fax functionality into existing systems and workflows through our online fax API. This can further streamline and automate operations, improving efficiency and reducing the risk of errors. Overall, this solution can provide a powerful and flexible way for businesses to manage fax communications online.

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