Two shadows holding hands

The differences between microservices and web services deal with different concepts in modern application design. A microservice is a small, independent, application that performs a highly focused service as well as possible. A web service is an internet-based interface that makes the “services” of one application available to applications running on different platforms. 

Since microservices are one of the most popular concepts in application development right now, they’re getting a lot more attention than web services. However, both concepts are highly relevant when building a modular, services-oriented application architecture – so it’s important to understand how both fit into the picture of modern app design.

In this article, we’ll use the following sections to explore the differences, advantages, and disadvantages of microservices and web services:

Need an API for your Microservice? Did you know you can generate a full-featured, documented, and secure REST API in minutes using DreamFactory? Sign up for our free 14 day hosted trial to learn how! Our guided tour will show you how to create an API using an example MySQL database provided to you as part of the trial!

Build Your Microservice Now

Microservices vs. Web Services: An Overview

In the simplest of terms, microservices and web services are defined like this:

  • Microservice: A small, autonomous application that performs a specific service for a larger application architecture.
  • Web service: A strategy to make the services of one application available to other applications via a web interface.

Both microservices and web services can be used to build application architectures. Here’s a brief description of both architectural styles:

  • Microservices application architecture: A modular, services-oriented application architecture comprised of loosely connected, independently running microservices. These microservices usually offer APIs so other microservices and apps can integrate with them.
  • Web services application architecture: A modular, services-oriented application architecture where the applications that comprise the architecture connect via web services. Developers can use web services to connect microservices, monolithic applications, and more to form a larger application. 

It’s common for modern, services-oriented application architectures to include a mix of microservices and monolithic applications. It’s also common for them to use a mix of APIs and web services to integrate the apps and microservices services that comprise them.

Microservices Application Architecture

A microservices-based application architecture breaks a traditional monolithic application into its component functions. Rather than programming all application functions into a single piece of source code – as a monolith does – the microservices architecture isolates each function as a small, autonomously-running application, i.e., a microservice, which it typically runs in a containerized environment. 

A group of microservices that make up a microservices-based application usually interconnect with each other through APIs (Application Programming Interfaces). When developing a microservices-based application like this, developers may use an API gateway – like DreamFactory – which offers an easy way to manage access to and establish integrations with the microservices that comprise the application.

How flexible are API connections for microservices?

APIs are the preferred method for connecting microservices because APIs support the widest variety of message formats (such as XML, XML-RPC, JSON, etc.) and the widest variety of message protocols (such as HTTP, HTTPS, MQTT, REST, and SOAP). 

As we’ll discuss in the next section, developers can also connect microservices apps via “web services” to form a web services application architecture.

For a more detailed overview of how microservices work, please read our guides “What Are Microservices?”

Web Services Application Architecture

Instead of carrying out a specific function on behalf of a larger application,  – web services provide a standardized, web-based interface that makes the services of an application available to other applications on the internet.

W3.org nicely sums up the role of web services:

A web service is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the web service in a manner prescribed by its description using SOAP messages, typically conveyed using HTTP with an XML serialization in conjunction with other web-related standards.

Since web services allow diverse apps to connect and interact with each other, they are more like the glue that developers use to connect individual apps and build a web services application architecture. In fact, web services are APIs – or rather, one of the many representations of APIs. Artjoker Blog explains this distinction:

[A web service] is only one of the many API representations that use HTTP protocol for connection with third-party software solutions (for fairness’ sake, we’ll note that in rare cases, this connection is established via the other transport protocols like SMTP).

Another way of seeing web services is to view them as an “HTTP wrapper” around an API. This HTTP wrapper presents different services – that belong to a specific application – through a web interface, so other applications or microservices can interact with those services, even when the connecting systems are written in different programming languages and running on different OS platforms. 

In this way a web service functions as a bridge – regardless of whether the connection is cloud-to-cloud, server-to-server, server-to-premises, cloud-to-premises, or client-to-server. This makes web services particularly valuable for enterprises that want to connect diverse software components running in different locations.   

There are some however understandable obstacles you’ll need to keep in mind when using web services:

  • ]The applications and web services that comprise a web services application architecture need to share the same message format (typically XML or JSON).
  • The applications and web services also need to share the same message protocol (HTTP, MQTT, REST, SOAP, etc.).  

Fortunately an advanced iPaaS solution like DreamFactory can quickly overcome this lack of connection flexibility by converting messages from one format/protocol to another. 

How Web Services Work

Here’s a quick overview of how a SOAP-based web service works to establish integrations between a third-party client and the application it offers services for:

  1. The web service is a web-based interface that allows clients (or third-party apps) to access the services of the application that sits behind the web service.
  2. The client calls the web service by sending a series of RPC (Remote Procedure Call) requests to the server that hosts the web service. The advantage of an RPC request is that it doesn’t matter what language the client and the application are written in. For example, if the client is written in .Net and the application in Java – both can still communicate through the web service.
  3. The web service responds to the RPC by returning XML data to the client. XML is a standard messaging platform that most programming languages understand.
  4. When transmitting the XML document to the client, the web service uses the messaging protocol SOAP (Simple Object Access Protocol) and sends the data through HTTP.

Comparing Microservices and Web Services

Let’s look at the similarities and differences of microservices and web services from several different angles:

Service Specificity

On the topic of “service specificity,” a  microservice carries out a very specific service or task. For example, the Facebook Messenger platform includes a specific microservice that handles file attachments. You can access this specific functionality by using Facebook’s Attachment Upload API

In contrast, a web service can offer one or or a multitude of services from a single application. This allows a web services architecture to organize access to the different services provided by an application. For an ecommerce application one web service could present customer-facing ordering and payment services, while another web service presents non-customer-facing inventory services. Even though access to these services is offered by separate web services, they couldl belong to the same application In this way, web services can help you manage and control access to the various services that belong to the same application.

Pluggability

With both microservices and web services application architectures, developers can easily add, remove, and upgrade the microservices and applications that form a larger application architecture. This modularity results in a more flexible, agile architecture because upgrades are faster, cheaper, and easier to achieve without disrupting the entire application. 

With microservices, the APIs that connect them offer greater flexibility because they support both HTTP and HTTPS, and they can establish connections between dissimilar message formats and protocols. 

Conversely, web services do not support HTTPS and the connected components must share the same message format and protocol. That being said, an iPaaS like DreamFactory can easily overcome the message format and protocol requirements of a web service connection.

Cost-Effectiveness

Microservices often run in containers. Since multiple containers can run on the same operating system kernel, this reduces costs by requiring fewer operating system licenses to run the various microservices that comprise a larger app architecture. Also, the universal connective capacity of APIs means that developers save time and money when establishing microservices API connections – as they can forego the labor required to build a hand-coded, point-to-point connection. Since web services are an HTTP-based presentation of APIs, they also forego the time and expenses of hand-coded, point-to-point integrations. Finally, the pluggable nature of both microservices and web services architectures makes upgrades faster, simpler, and more cost-effective to achieve. 

Resilience

In microservices and web services architectures, the failure of one microservice or application is less likely to result in a cascade failure that affects the rest of the ecosystem. In both cases, developers can implement a circuit breaker design pattern to detect service failures and prevent them from disrupting other microservices or applications connected to the system. 

Language and Platform Agnostic

Developers can create both microservices or web services architecture by connecting applications running on any platform written in virtually any programming language. This gives developers the freedom to choose the most suitable languages and platforms for the different microservices, apps, and web apps that comprise an architecture. It’s also easy for them to establish premises-to-premises, premises-to-cloud, and cloud-to-cloud integrations. 

Smaller Development Teams

Microservices and web apps both allow for smaller, more focused, and easier-to-manage development teams. Managers can assign ownership of each web service or microservice to a small development team, allowing teams to work more independently and granularly on perfecting a single aspect of the application – without the fear of coding conflicts with other systems. 

A difference to note is that web services development teams must stay on the same page regarding the common messaging formats and protocols shared across the web service integration.

When Are Web Services Appropriate?

If you’re developing a modern application architecture – or managing a large enterprise IT infrastructure – there’s a good chance you’ll need to integrate a mix of microservices and monolithic applications, and a mix of web services and APIs connect these diverse systems. While it’s true that microservices and API connections are getting the most attention these days, there are some situations when web services are better for connecting applications:

  • When organizing access to different services offered by a single monolithic application, a web service allows you to create a service-oriented architecture that makes specific services from the monolith available through different web services. This helps you manage and organize access to different aspects of the same monolithic application.
  • Since each microservice has its own connection to a corresponding database, microservices architectures can be taxing on system resources when all of the microservices are constantly calling their databases. Conversely, a monolithic application requires fewer database connections and calls, which can save on system resources. With web services connections, developers can still benefit from a service-oriented architecture, while simultaneously reducing system slowdowns caused by too many database calls. 

Build Connection for Web Services and Microservices the Easy Way

After reading this guide, you should have a better idea of what microservices and web services are — and how microservices and web services based applications are different. You should also be able to recognize the situations when web service connections offer a better solution than APIs. 

If you’re in the process of developing a new application or IT infrastructure, the DreamFactory iPaaS can blow through your integration bottlenecks. As an advanced API gateway and web services connection solution, DreamFactory can automatically convert XML to JSON and SOAP to REST for web services integrations. Moreover, the platform features a point-and-click interface to instantly generate REST API for any system you want to connect. 

Sign up for a hosted trial of DreamFactory now! 

Related Articles

What are Containerized Microservices, ESB vs Microservices: Understanding Key Differences, API Trends: Monolithic vs Microservices, Microservices Examples: How Amazon, Netflix, Uber, and Etsy Broke Their Monoliths and Scaled to Unprecedented Heights with Microservices, What are Micro Apps on iOS?