How Do You Choose Between Microservices and Monoliths?

Building mobile apps means making hundreds of decisions about how your backend should be structured—and honestly, one of the biggest questions I get asked is whether to go with a monolithic architecture or split everything into microservices. It's a bit mad really, because there's no simple answer that works for everyone. The choice between microservices vs monoliths isn't just about following the latest trends; it's about understanding your specific needs, your team's capabilities, and where you want your app to be in two years time.

I've built backends both ways over the years, and I can tell you that both approaches have their place in app architecture. Sure, microservices get all the attention these days—everyone wants to talk about how they're more scalable and flexible. But here's the thing: I've seen plenty of apps that would have been better off starting with a simple monolithic structure. And I've also worked on projects where microservices saved the day when we needed to scale rapidly.

The architecture decision you make today will impact every feature you build, every developer you hire, and every scaling challenge you face tomorrow.

What really matters is matching your backend development approach to your actual situation, not just copying what the big tech companies are doing. Your team size, budget, timeline, and growth plans all play a role in determining the right software design patterns for your project. Actually, most successful apps I've worked on started simple and evolved their architecture as they grew—which is probably the most practical approach for most mobile app projects.

Understanding Monolithic Architecture

Right, let's start with the basics—what exactly is a monolithic architecture? Think of it as building your entire app as one big, self-contained unit. Everything lives together: your user authentication, payment processing, content management, and all the other features are bundled into a single codebase that gets deployed as one piece.

I've built plenty of monolithic apps over the years, and honestly? They're not the outdated dinosaurs some developers make them out to be. When you're starting a new project, a monolith can be your best friend. You write all your code in one place, you deploy it all at once, and debugging is straightforward because everything's right there in front of you.

Key Characteristics of Monolithic Apps

Here's what defines a monolithic architecture:

• Single deployable unit—everything goes live together
• Shared database across all features
• Direct function calls between different parts of your app
• One technology stack throughout the entire application
• Centralized logging and monitoring

The thing about monoliths is they're predictable. When a client comes to me with a new app idea, I often recommend starting with a monolithic approach. Why? Because you can move fast, make changes quickly, and you don't have to worry about managing multiple services talking to each other. It's like having all your tools in one toolbox instead of scattered across different rooms.

But here's where it gets interesting—as your app grows and your team expands, that single codebase starts feeling a bit cramped. Different developers working on different features begin stepping on each others toes, and suddenly what felt simple becomes... well, less simple. That's when the conversation about microservices usually starts happening.

Breaking Down Microservices Architecture

Right, so we've talked about monoliths—now let's get into microservices. I'll be honest, when microservices first started gaining traction, I thought they were just another tech buzzword that would fade away. Boy, was I wrong! But here's the thing: they're not magic, and they're definitely not right for every project.

Microservices architecture breaks your app down into small, independent services that each handle one specific job. Think of it like having a team of specialists instead of one person trying to do everything. Your user authentication runs as one service, payment processing as another, notifications as a third—you get the idea.

Each service has its own database, its own codebase, and can be deployed independently. This means if your payment service crashes, your users can still browse products and add items to their cart. The services talk to each other through APIs, which gives you loads of flexibility in how you build and maintain things.

Key Benefits of Microservices

• Scale individual services based on demand (your payment service might need more resources during sales)
• Use different technologies for different services—Python for machine learning, Node.js for real-time features
• Deploy updates to one service without touching the others
• Different teams can work on different services without stepping on each others toes
• If one service fails, the others keep running

But—and this is a big but—microservices come with their own headaches. Network calls between services add latency. Debugging becomes more complex when you're tracking issues across multiple services. And honestly? Managing deployments across dozens of services can be a nightmare if you don't have the right tooling in place.

Start with a monolith and extract services as you grow. I've seen too many teams jump straight into microservices and spend months fighting deployment pipelines instead of building features their users actually want.

When Monoliths Make Perfect Sense

Right, let's talk about when monoliths aren't just acceptable—they're actually the smart choice. I know everyone's obsessed with microservices these days, but honestly? Sometimes a good old monolith is exactly what your mobile app needs.

If you're building your first app or working with a small team, monoliths are brilliant. They're simple to develop, test, and deploy. You don't need to worry about service communication, network latency between components, or managing multiple databases. Everything lives in one place, which means debugging is straightforward—when something breaks, you know where to look.

Perfect Monolith Scenarios

• Startups and MVPs where speed to market matters more than perfect architecture
• Small to medium apps with straightforward business logic
• Teams with fewer than 8-10 developers who can all understand the codebase
• Apps with tightly coupled features that naturally belong together
• Projects with limited DevOps expertise or infrastructure budget

Here's the thing—most successful apps started as monoliths. Instagram, Twitter, even Netflix began with monolithic architectures. They only moved to microservices when their scale demanded it, not because microservices were inherently better.

The beauty of monoliths is their simplicity. You deploy one thing, monitor one thing, and scale one thing. For mobile apps especially, where you're often dealing with user authentication, content management, and API responses, having everything in one cohesive system makes perfect sense.

Don't let architectural trends dictate your technical decisions. If your app serves thousands of users happily with a monolith, there's absolutely no reason to complicate things. You can always refactor later when—and if—you actually need to.

The Case for Choosing Microservices

Right, so when does it actually make sense to go down the microservices route? I mean, after hearing about all the complexity, you might wonder why anyone bothers! But here's the thing—there are genuine scenarios where microservices become not just helpful, but pretty much necessary for your app's success.

If you're building an app that needs to handle millions of users, microservices start looking very attractive. Take a social media app, for instance. Your photo processing service might get hammered while your messaging feature ticks along nicely. With microservices, you can scale just the bits that need it without wasting resources on everything else. Its like having different sized engines for different jobs rather than one massive engine doing everything poorly.

Team dynamics play a huge role too. If you've got multiple development teams working on different features, microservices let each team move independently. The payments team can deploy their updates without waiting for the user profile team to finish their work. No more "we can't release because Dave's still fixing the notification bug" situations!

The beauty of microservices isn't in the technology itself, but in how it mirrors the way successful organisations actually work—small, focused teams delivering specific value

Language diversity is another big win. Maybe your recommendation engine works brilliantly in Python, but your real-time chat performs better in Node.js. Microservices don't care—use whatever works best for each job. Plus, if one service crashes, the rest of your app keeps running. Your users might lose the ability to post comments, but they can still browse and make purchases. That's the kind of resilience that keeps businesses alive during those 3am server panics we all dread!

Team Size and Development Considerations

Your team size actually plays a huge role in deciding between monoliths and microservices—and honestly, this is where I see loads of companies get it wrong. They read about some tech giant using microservices and think "right, that's what we need" without considering their team structure.

Here's the thing: microservices require serious coordination. You need teams who can work independently but still communicate effectively. If you've got a small team of 3-5 developers, managing multiple services becomes a nightmare. One person ends up maintaining several services, context switching constantly, and debugging becomes... well, bloody difficult when issues span across services.

The Two-Pizza Rule Actually Matters

There's this concept where each microservice should be maintained by a team small enough to be fed by two pizzas (roughly 6-8 people). But here's what they don't tell you: you need multiple of these teams to make microservices work properly. A single "two-pizza team" managing ten microservices isn't really following the pattern.

With monoliths, your entire team can understand the whole system. New developers can contribute faster because everything's in one place. Code reviews are simpler, debugging is straightforward, and deployment coordination is straightforward rather than complex.

Skill Requirements

Microservices demand a broader skill set across your team. You'll need people comfortable with:

• Container orchestration (Docker, Kubernetes)
• Service mesh configuration and monitoring
• Distributed system debugging techniques
• API design and versioning strategies
• Database per service patterns
• Event-driven architecture principles

If your team is still learning the basics of mobile development, adding microservices complexity on top is asking for trouble. Start with a monolith, grow your team's expertise, then consider breaking things apart when you have the skills and team size to support it properly.

Performance and Scaling Realities

Right, let's talk about what actually happens when your app gets busy. I mean really busy—the kind of traffic that makes your server cry and your monitoring alerts go mad. This is where the rubber meets the road with microservices vs monoliths, and honestly? Both approaches can handle massive scale, but they do it very differently.

Monoliths get a bad rap for scalability, but that's not entirely fair. Some of the world's busiest applications run on monolithic architectures and handle millions of requests just fine. The thing is, you scale the entire application as one unit—which means if your user authentication system is getting hammered, you're also scaling your payment processing and email services even though they might not need it. It's a bit wasteful, sure, but its also wonderfully simple.

Monitor your actual bottlenecks before making scaling decisions. Most performance issues come from database queries or external API calls, not your architecture choice.

Microservices shine when you need granular scaling. Your image processing service can run on powerful machines whilst your simple user preferences service sits happily on smaller instances. But here's what nobody tells you—network latency becomes your new enemy. Every service call adds milliseconds, and those milliseconds add up fast when you're making dozens of internal API calls to render a single screen.

Scaling Patterns That Actually Work

• Database read replicas solve 80% of monolith performance issues
• Caching layers work brilliantly with both architectures
• Load balancers are your friend regardless of your choice
• Auto-scaling works better with microservices but costs more to manage
• Content delivery networks boost performance for both approaches

The real scaling challenge isn't technical—it's operational. Microservices require sophisticated monitoring, distributed tracing, and proper service mesh configuration. Monoliths need careful resource management and smart caching strategies. Both can fail spectacularly if you don't plan properly, but they fail in very different ways.

Making the Architecture Decision

Right, so you've read all about the pros and cons—but how do you actually make this decision? I mean, both architectures can work, both have their place, and honestly, there's no magic formula that spits out the perfect answer.

The truth is, most of the time your constraints make the decision for you. If you're a two-person startup with limited funding, microservices probably aren't your friend right now. If you're a massive company with dozens of development teams and complex deployment requirements, a monolith might hold you back.

Start With Your Current Reality

Here's what I ask my clients to consider first:

• How many developers do you have right now? And how many will you have in six months?
• What's your deployment experience like? Do you have DevOps people who know containerisation inside out?
• How complex is your domain? Are you building a simple e-commerce app or something that needs to handle millions of transactions?
• What's your timeline? Monoliths generally get you to market faster initially
• How's your budget looking? Microservices infrastructure costs add up quickly

Actually, here's something most people don't think about—you can always start with a monolith and break it apart later. It's called the "strangler fig pattern" and it works brilliantly. You gradually replace parts of your monolith with microservices as your team grows and your understanding of the domain improves.

The Hybrid Approach

You know what? You don't have to go all-in on either approach. I've seen successful apps that use a monolith for their core business logic but split out specific services—like image processing or payment handling—into separate microservices. Sometimes the best architecture decision is the one that acknowledges your app isn't just one thing.

After building mobile apps and their backend systems for nearly a decade, I've watched countless teams struggle with this decision—and honestly, it's gotten more complex over time. The choice between microservices vs monoliths isn't just about app architecture; it fundamentally shapes how your team works, how fast you can ship features, and how much you'll spend on infrastructure.

Here's what I've learned from all those projects: there's no universal right answer. The best backend development approach depends entirely on your specific situation. If you're a small team building an MVP or working under tight deadlines, a monolithic architecture will probably serve you better. It's simpler to develop, easier to debug, and you won't waste time managing distributed systems complexity when you should be focusing on user feedback.

But if you're looking at serious scalability requirements—think thousands of concurrent users or complex business logic that different teams need to work on independently—then microservices might be worth the extra complexity. The key word there is "might." I've seen too many teams jump into microservices because they thought it was the "modern" way, only to spend months fighting deployment issues instead of building features users actually wanted.

My advice? Start with a well-structured monolith and keep your software design patterns clean. Make sure different parts of your application are properly separated, even within a single codebase. This gives you the flexibility to extract services later when—and if—you actually need to scale specific parts of your system. Remember, you can always break things apart later, but putting them back together is much harder.

The best architecture is the one that lets your team move quickly and your app perform reliably for your users.