Monolithic vs. microservices architecture: The pros, cons, and everything else

It’s not something you might immediately be aware of, but software architecture plays a significant part in the experiences that you get when you visit a website. Software architecture can affect page load times, site uptime, updates, SEO, security, and more — all factors that make it an important development consideration. 

When software architecture serves content well, it’s likely you won’t notice any issues, but if there’s a mismatch, the browsing experience can get frustrating. If you’re running an ecommerce website, for example, page issues can drive customers to competitors, damaging both your bottom line and your reputation.  

That said, two types of software architecture stand out from the rest when it comes to designing and building digital experiences: legacy monolithic architectures and microservices architecture.

Both types of architecture are used widely by companies across the world, but research suggests that microservices are gaining ground on their legacy monolithic counterparts. The microservices market is expected to reach a value of $15.97 billion by 2029, with a compound annual growth rate of 21.0% — that momentum driven by uptake from competitive, successful companies, the introduction of serverless computing, and the opening up of online channels to mobile and tablet users, wearables, and the Internet of Things (IoT).

So, assuming you have a choice between monolithic and microservices architecture when you build your website, or if you’re thinking about switching from a monolithic system, it’s going to be useful to know which architecture will suit your needs best. 

In this post, we’ll get into the “what” and the “why” behind the monolithic vs. microservices discussion, offering an overview of both types, and comparing their core capabilities as they pertain to running a website and managing content.

An overview of architectures

What is a monolithic architecture?

Considered the more traditional of the two architectures, monolithic systems are provided by a single vendor and package a series of business capabilities — or functions — into one.

In monolithic architecture, the administration of backend code and business logic is tightly coupled to the frontend presentation of website content, which means that changes or updates to web pages require a degree of technical expertise. That coupling also means it’s difficult to upgrade monolithic architecture, or integrate new capabilities from other vendors. 

One reason applications supported by monolithic architecture are favored is that they provide out-of-the-box functionality and consistent technical support, which is ideal for startups or companies with small teams that need to create and launch their websites quickly. 

What is a microservices architecture? 

Microservices architecture is an evolution of monolithic architecture. 

In microservices architecture, backend administration is decoupled from frontend presentation. This separation untangles content from code, and makes website development, and content management, more flexible and open to integrations or upgrades. In this environment, multiple services can function independently without affecting other services, so content team members may, for example, make changes to pages without disrupting code. 

That flexibility means that businesses can build their website’s tech stack from scratch, populating it with an array of smaller, modular components — or microservices — that provide collective functionality.  

Microservices architecture is sometimes called composable architecture, or MACH architecture (microservices, APIs, cloud and headless), because it enables development teams to mix and match the tools needed to carry out a specific project, or meet individual and team preferences. These tools are considered loosely coupled, with communication between each occurring via application programming interfaces (APIs). Note that each microservice has its own database, unlike monolithic architectures which share a single database. 

In a microservices environment, businesses can constantly evolve their tech stack to meet the needs of their users, integrate modern tools, and react to changing market demands.

Comparing core capabilities

Now that we understand the basics of monolithic and microservices architectures, let’s compare core capabilities and key benefits.  

Development

Microservices architecture: While microservices play well with each other, they have no problem doing their own thing. To get more technical, the individual services included in the microservice “ecosystem” are both programming language agnostic and framework agnostic. This means that you and your team have flexibility when modeling and building your tech stack. You can be strategic in the components, coding languages, and frameworks you select, choosing those that play to your skill set or to the needs of a specific project. 

Similarly, microservices architectures can be managed on an individual basis by a smaller team — a factor that often streamlines the buy-in and onboarding processes. This approach speeds up development cycles, enhances site agility, and increases team productivity.

Monolithic architecture: Since they deliver prepackaged functionality, monolithic applications lack the developmental flexibility of microservices architecture, and favor a single programming language. 

This lack of flexibility can present a learning curve for developers who may not be well versed in the given language and framework. Furthermore, because the business logic and functional components of the application are coupled across the back end and front end, they cannot be managed independently. Instead, they must be managed by individuals, or a team of individuals, who understand their entire scope. Depending on how large the monolithic application is, retaining this level of technical information and responsibility can be taxing on smaller teams.

Deployment and delivery

Microservices architecture: Organizations that want to make quick or frequent updates to their tech stacks typically prefer microservices architecture.

In a microservices environment, it’s possible to deploy individual components independent of the rest of the framework, rather than redeploying (and disrupting) the entire suite of services. As a result, release cycles can be spontaneous (i.e., continuous integration and continuous delivery), reflecting changes in the marketplace, greater competition, and new customer demands. 

Monolithic architecture: The deployment and development of monolithic applications is often more complex and drawn out. Instead of small-scale, incremental deployments, monolithic applications must be deployed in their entirety, every time an update or change is made.

Because this process can be time-consuming, monolithic deployments are tied to a strict schedule, making business processes less agile, and reducing speed to market. In these contexts, the deployment of an application is treated as a project rather than an easily (and frequently) iterated product. 

Integration

Microservices architecture: In microservices architecture, the focus is on endless iteration, and the freedom to constantly add new business capabilities and features. These integrations can come from a third party or be custom built; moreover, they can be introduced into the existing framework without disruption. The microservices architecture powering a website may be extensive: for example, Amazon’s desktop application calls up to 150 microservices to build a web page at a given time. 

Monolithic architecture: Because monolithic architecture includes a suite of tightly coupled tools and business capabilities provided by a single vendor, it can be difficult to integrate both third-party and custom-built applications. Development teams may be able to create workarounds to patch in these tools, but this adds complexity, and makes the architecture more susceptible to security issues. Monolithic applications may offer integrations that are developed or permitted by the vendor, but these vendor-locked options may not be cost-effective, or align with business objectives.

Scaling

Microservices architecture: Because components within a microservices architecture are separate, and loosely coupled via APIs, they can be managed and scaled independently of one another. This offers a huge financial benefit because you only pay for the components you need, and can swap out resource-heavy components for efficient alternatives. 

Monolithic architecture: Monolithic applications, and their large, single codebases, make scaling complicated. Scope for integrations is often limited by the vendor and, when greater capacity and bandwidth are needed, developers must scale the whole system at once,  which can be costly and labor-intensive.

Reliability

Microservices architecture: Microservices are inherently more resilient than their monolithic counterparts. When one microservice fails, the functionality of the wider application typically remains — it might be less complete, but it’s still accessible and functional for users. Similarly, microservices architectures enable teams to test new components thoroughly prior to integration without disrupting the wider framework to further reduce failure post-deployment.

Monolithic architecture: Errors that occur in a monolithic application can take the whole framework down. While debugging is relatively straightforward, since there is only one codebase, DevOps must nonetheless redeploy the whole application. Depending on the application’s size, this can result in significant periods of downtime, which can be frustrating for the end user.

When to use monolithic and microservices architectures

The comparative strengths of monolithic and microservices applications isn’t a factor businesses should account for when selecting an architecture — instead, teams should take a more holistic perspective.

For example, since monolithic architectures use a single codebase, they are better suited to smaller or simpler website tech stacks that won’t need extensive upgrades or adjustments in the future (as far as that can be anticipated). Meanwhile, the scalability and flexibility of microservices architecture make it ideal for complex applications in distributed systems, or for websites with plans to scale.

However you choose your software architecture, it’s important to consider these broader contextual factors: how and where will users access your website? What kind of marketing campaigns will you run? What languages do you need to publish content in? What features might users want in the future? The answers to these questions should inform your development strategy, and how you model content in your new architecture. 

If there are substantive benefits to both a monolithic and a microservices approach to your tech stack, it’s worth noting that the software architecture you choose doesn’t have to be either/or. There may be scope to adopt a microservices architecture and integrate monolithic tools to fill specific needs — Contentful customer CodeDay’s microservices tech stack is a good example of that approach in action.

Migrating to a microservices architecture

If you do decide to migrate from a monolithic to a microservices architecture, you’ll need to be strategic about it. 

Your plan should start with an outline of the features and functionalities that you want for your website, and then research into the microservices that you’ll need to integrate to achieve your goals. You’ll also need to decide how to transition to the new environment. You may opt to make the switch in phases, or develop the new architecture independently and switch in one go. 

You can learn more about migrating from monolithic applications to microservices ecosystems in our CMS migration guide. 

More resources to help you select the right architecture

If you’ve followed our monolithic vs. microservices discussion this far, it’s likely you have an idea which architecture best suits your website. Before you kick-start any development work, here are a few additional resources to help you get the most out of your new framework:

• White paper: How to assess the performance of your composable architecture

• Checklist: Find the right solution for your scaling business

• Guide: The Composable Content guide

Explore the microservices ecosystem with Contentful

Built with an API-first design philosophy, the Contentful® Composable Content Platform is the gateway to an ecosystem of microservices. We understand how precious flexibility and future-proofing are to content management strategies: you can plan your tech stack down to the smallest components, create content that can be used and reused across channels, and scale easily when the picture changes. 

We’ve helped some of the world’s biggest brands make the transition from outdated monolithic applications to create their own microservices architecture — expanding their footprints across digital channels, and connecting with new audiences and users. So, if you’re ready to begin your own microservices journey, we’re ready to help you take that first step.

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