API vs Web Services: What Are the Differences?

Published on 08-08-2021

As 55% of companies use APIs to support their revenue streams, their importance is obvious in the world of technology. But what about web services? How can you use them to support your company as it grows?

This article will help you understand the myriad of differences between an API and a web service. It will define what each is, as well as go over the different types of web services available to you. With this information, you will be able to move forward and make decisions on which is the best choice for tasks you need to complete.

What is an API?

When you wish to create a method for allowing one application to interact with another, you must create an API. This Application Programming Interface is a set of functions and procedures. You can use such procedures to allow any other program to communicate with the application you are producing.

Generally, when discussing an API we mean one that works over the Internet. Although this is not always the case. Even two applications on the same computer that needs to talk to one another are making use of APIs to ensure this can happen.

Some examples of APIs you may have used include:

  • Using your Google account to log into a non-Google website
  • Attaching an authenticator app to an online profile
  • Logging into Twitter using an app on your smartphone

What is a Web Service?

While APIs generally expand on an application's functionality, a web service is like a very specific type of API. Web services are resources that center around a network to perform a specific function.

One often-repeated quote is that "All web services are APIs, but not all APIs are web services."

Web services use XML to represent the data they communicate back and forth. This allows them to present their information regardless of the format. It can thus use any operating system, platform, or any other factor that might otherwise get in the way.

Any client application and web service are not bound to one another. This means that a client or web service can update over time without always requiring the other to also update.

This loose coupling means that you can manage the web service a lot easier and you can develop integrations between the systems a lot faster.

Examples of Web Services

There are two main types of web services. These are SOAP and REST.

SOAP: Simple Object Access Protocol is, as the name suggests, a protocol. It was the standard for web service creation for a long time before the industry developed REST.

It uses a standard HTTP protocol, which allows it to work through firewalls or other network add-ons without someone needing to change it. But, its complex format makes it a bit slower than other communications methods such as COBRA and ICE.

SOAP was first developed by Microsoft for assisting with object access. These days, it is often used if you need to use specific security protocols such as WS-Security, or if you need more security for data privacy.

SOAP is also often used when network connections are prone to failure. This is because it has in-built compensation for failed communication. This is not found in many other protocols, allowing it to succeed where other systems fail.

REST: This is also known as a representational state transfer. The REST is a set of constraints that exists for working with components. This can include hardware components, media files, or even any specific files.

REST does not only work with XML, it allows you to make use of XML, but also plain text, HTML and JSON formats for its data. It is also not a protocol like SOAP, it is instead an architectural style that has specific constraints applied to it. If these constraints are not followed, it is not considered "RESTful" by its users.

While REST and SOAP are separate, REST can make use of SOAP's protocols. It can do this due to its nature of only being an architectural pattern, and can then use SOAP to enact its web service actions.

API: Pros

The positive elements of using an API are as follows:

CRUD: When working with an API you are able to use the four basic operations of persistent storage. These are Create, Read, Update and Delete. The HTTP verbs of "Get, Put, Post and Delete" are analogous to these operations and as such work to give you all the basic commands you will need.

Exposing service data: API is able to assist you in exposing service data when utilizing the API within the browser. This lets the application using the API operate more efficiently.

HTML core : As API is based on HTTP, it is very easy to define or expose. This allows you to work moving forward in a way that is RESTful.

API: Cons

Some of the drawbacks of APIs are the following:

Knowledge: You must have a level of programming expertise in your team if you wish to create or make use of an API. This means you will have to pay more for that sort of knowledge in your team.

Maintenance: Not only will you need to create an API, but you will need to maintain it. Technology changes and adjustments to software will mean that an API may not always be up-to-date. This maintenance cost may end up very high.

Scalability: You must design scalability into the core architecture of any API you create. This means that if you have not planned for it from the get-go, you will end up doing more work in the future.

Many companies offer go-to solutions and "silver bullets" for scalability. Unfortunately, they often inflate their capabilities for marketing purposes.

Time: While an API can be a very powerful tool, it can be a long process to get it up and running. This means that you could end up investing a lot of effort and money into the system before you know if it is the right thing for you.

Web Services: Pros

The positive traits of web services are the following:

Communication: Web services are for the most part data-exchange systems that use XML. They offer opportunities for faster communications channels within or outwith your organization.

Independent: Each web service works without interacting with other systems in your network. This allows them to be free of requirements involving other areas of your organization.

Interoperability: A web service is able to exchange data between different programs and platforms. Because of this, it suits attempts to solve interoperability problems that exist in your organization.

Browser Compatability: Many web services were first designed to work from a web browser via a web page. This allows them to retrieve data through a user interface that is accessible and a positive experience for users.

Modular: Web services are often built of smaller components that you can reuse in different applications. This can offer you the opportunity of saving time and money on future projects. You can do this by taking components that you built in an earlier application and using them moving forward.

Use of Standards: Web services are often deployed using common Internet standards such as Apache and Axis2. This allows it to be compatible with a great many other online services and applications with very little work. Especially when compared to other data communications systems.

Web Services: Cons

We have written about some negative traits of web services below:

HTTP Reliance: While the HTTP protocol is old and oft-used, it can be unreliable. It does not guarantee that a response to any data request will occur. This means that you must handle such a lack of response in any application programmed to use a web service.

Incompatibility: Several more recent web technologies are incompatible with existing web services. For example, XMLHttpRequest and Semantic Web. This means that you must create unique solutions to deal with these emerging technologies.

Tech Issues: Some web services have problems with specific hardware. As you get more customers, you may find that you come across more and more specialized requirements. The extra work to support these will take time and money away from other projects or priorities.

Verbose: Although a web service is not limited to using XML, this can be a drawback. A web service with a poor design may have very complicated data packages that may not be useful for you or your purposes.

Further Thoughts

You should now have a much greater understanding of what an API or web service is and how each one offers its own advantages or disadvantages. It is understandable, though, if you still have several questions on which you should use. Lucky for you, we are here to help you determine that.

Our specialists can help you comprehend exactly how to use either an API or web service, as well as what we can do to make that even easier. So, get in contact today and see what we can do for you moving forward.

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