Web API vs REST API: What's the Difference?

The differences between a WEB API and a REST API are very subtle. Here, we explore how they're different to help you decide which is right for your project.

Most of us already know what an API is: an interface through which two applications interact, exchanging relevant data to enable them perform their functions. Think of when someone hails an online taxi. The taxi app communicates with a location app like Google Maps to show you the movement of the driver. This communication is enabled by critical resource requests via an API. The application that requests for a resource from another application is known as the client while the application giving the resource is known as the server. This is easy. But if you are a software developer getting down to serious development work, there's more to APIs and you've probably come across so many terms flying around such as “Web API" and «REST API». What do they mean, and how are they different? Find out in our detailed guide. .

What is a Web API?

Just as the name suggests, a Web API is simply an API that is used to facilitate requests on the web. The communication is channeled through the HTTP protocol.  A Web API can be used for web servers or browsers. For example, when you type a URL into your web browser, your browser makes a request to a web server. The server then uses the Web API to process the request and send back the data that you requested. In this way, the Web API acts as a bridge between the two sides.

Another common use for a Web API is in social media.  Many social media applications use APIs to allow third-party developers to create applications that interact with the social media platform. This allows developers to create innovative new applications that would not be possible without the API.

This is not a technology but a concept, meaning a Web API can be implemented by using various technologies. The key point to note here is that a Web API is particularly best suited for use on web applications.

What is REST API?

A REST API is an API that uses the REST architecture (Representational State Transfer ). REST is an approach that is used to design networked applications that are scalable and maintainable. A REST API defines a set of operations that can be invoked, typically using GET, POST, PUT, and DELETE methods. A REST API can be used to access data from a web server or another application. For example, a developer might use the GET method to retrieve a list of users from a database, or the POST method to create a new user. Developers can use a REST API to make it easier to work with data from different sources, and it can also help to improve the scalability of an application.

Key differences between Web API and REST API

The underpinning difference between a Web API and a REST API is simply that Web APIs are used for web-based resources. This could be a website, a blog, or anything that can be accessed through a web browser. REST APIs, on the other hand, are used to access resources that are located on different systems including servers. For example, REST API can be used to enable a website to access resources in an ERP system. They use the principles of REST (Representational State Transfer) to manage communication between the client and the server.

Here are more specific differences between Web APIs and REST APIs

Differences in Scope

Web APIs are often lighter in nature, meaning they are designed to work best for less complex applications that are web-based. These could include applications accessed via desktop or smartphones. Due to their simplicity and lighter footprint, they are an optimal choice for applications that do not require heavy data processing or complex interactions with multiple systems.

On the other hand, REST APIs are designed to handle more complex systems, making them a preferred choice for more intricate applications and integrations. Thanks to the principles of the REST architecture, REST APIs can effectively manage communication with various systems and handle a broad range of operations, thereby aiding in the creation of more robust and complex applications.

Differences in Response Codes

Web APIs can return a variety of response codes, giving a more granular understanding of the status of the request. This capability makes Web APIs a better choice if detailed error handling is a significant concern for your application.

On the contrary, REST APIs also use a comprehensive range of HTTP status codes that offer specific information about the outcome of a request. These codes range from 200 (OK) for successful requests, to 400 (Bad Request) for requests with incorrect syntax, 401 (Unauthorized) for failed authentication, 404 (Not Found) for non-existent resources, and 500 (Internal Server Error) for issues on the server side, amongst others. This range of response codes makes REST APIs quite effective at providing informative feedback about the requests they handle.

Differences in Data Formatting

Web APIs provide flexibility in data formatting. They can return data in various formats, such as XML, JSON, etc., depending on the requirements of the application. This flexibility in data formatting makes Web APIs a suitable choice if your application requires handling different data formats.

In contrast, REST APIs predominantly use JSON as the data format. JSON's simplicity, readability, and widespread adoption have made it the primary choice for data exchange in REST APIs. However, it's worth noting that REST APIs are not limited to JSON and can support other formats like XML, YAML, etc., if properly implemented. But JSON remains the most commonly used format due to its compatibility with modern web applications.

When to use Web API vs REST API

If you need to access data that is publicly available on a website, then a Web API is the way to go. For example, if you want to retrieve data from a weather website, you would use a Web API. Many governments and businesses use Web APIs to serve requests from developers who then go ahead to use this data to develop applications that many people use.

If you need to access data that is not publicly available or that is located on a server or some internal system like ERP, then you will need to use a REST API. For example, if you want to retrieve data from a database, you would use a REST API.

Web APIs are great for projects that need a lot of interactivity. They're perfect for applications that need to be able to communicate with a server in real time.

REST APIs, on the other hand, are perfect for applications that don't need as much interactivity.

Conclusion

With the increasing diversity and complexity of applications both online and offline, both organizations and developers need to make the right decisions on which APIs to use where. This makes it easy to create systems that are easy to communicate and serve users better. Failure to choose the right API can result in systems that users will struggle with. Can you imagine what would happen if for example, a bank’s online banking app cannot communicate efficiently with the bank's core system that holds customer accounts. This would waste customers' time and the bank’s reputation will go up in smoke. Or just imagine if developers were unable to conveniently  use the Google Maps API. It means all the super good applications that rely on Google Maps will not function well, leave alone existing in the first place. It also means that Google Maps will not make sense. The essence of APIs is therefore to create an enabling ecosystem, where different systems support each other to fulfill the requests of users.  So be sure to get it right. Choose the right API.