Monoliths and Microservices -Architecture is a foundational aspect of software development that has a major influence on how applications are built, deployed, and iterated. As such, having a solid understanding of architectural styles and patterns is crucial for product managers to be effective in their roles.
While architects and engineers handle the technical details and implementation of architectures, product managers need to comprehend the core models at a high level. This enables Product Managers to make better decisions about product planning, prioritization, technology selection, and more.
Monoliths and Microservices
The two predominant application architectures that all Product Managers should have fundamental knowledge of are monolithic and microservices architectures. This article will provide an overview of what each architecture entails, their respective pros and cons when each style makes sense, and why grasping these architectures is vital for product managers.
We’ll cover the key differences between monolithic vs. microservices, typical use cases, how architectural decisions impact velocity and iteration, and strategies for migrating from monoliths to microservices over time. By gaining a solid understanding of these core architectural models, PMs can collaborate more effectively with technical teams, plan smarter roadmaps, and build products that meet customer needs.
What is a Monolithic Architecture?
A monolithic architecture consists of a single unified application. Unlike microservices which break software into independent modular components, monolithic applications have their user interface and business logic tightly coupled in a single program.
Monoliths contain a client-side user interface (UI), server-side application logic, and a database all bundled together in one software package. This means that any change made to one module, such as a new UI feature, requires building and deploying an updated version of the entire monolithic application.
Some benefits of monolithic architectures include:
- Simplicity and ease of development – everything is in one place, less integration complexity
- Straightforward testing since all modules are together
- Easy deployment of the full application
- Better performance when compared to microservices in simple apps, as calls remain within the app
However, monoliths also come with notable drawbacks, such as:
- Lack of modularity – difficult to isolate components for independent development or reuse
- Scaling challenges – the entire app must be scaled even if only a part is bottlenecked
- Tight coupling makes iterative improvement difficult – changes impact many areas
- Single point of failure – bug or outage brings down the whole system
- Difficult to adopt new technologies – monoliths are typically tied to one tech stack
So in summary, monolithic applications can work very well for simple software with limited scope, but they become unwieldy on large complex applications requiring frequent changes. Understanding monoliths versus microservices architectures allows PMs to make smarter technology decisions.
Monolithic Architecture Use Cases
Monolithic applications make the most sense for software projects with a smaller codebase and limited scope. The simplicity of developing and deploying a single unified app is advantageous when engineering resources are constrained or requirements are straightforward.
Some examples where monolithic architectures thrive include:
- Early-stage startups with a minimal viable product (MVP)
- Internal business applications with simple, defined requirements
- Prototyping or proof-of-concept applications
- Solo developer or small team projects
- Apps requiring high performance and low latency
Many successful companies began with monolithic architectures early on when their products and teams were small. As the app and organization scale, migrating to microservices becomes necessary. But starting with a monolith allows for speed to market and lean development.
Some notable companies that utilized monolithic architectures effectively in their early stages include PayPal, Amazon, Facebook, and Twitter. While they eventually transitioned to microservices over time, beginning with a monolith facilitated rapid validation and iteration.
So monolithic architectures can serve as an excellent starting point, even if the longer-term plan involves microservices down the road. The key is determining the inflection points where modular services become advantageous.
What are Microservices?
Microservices are an application architecture composed of independently deployable modules and services. Rather than the single unified program of a monolith, microservices architecturally decompose software into smaller, decentralized components.
Each microservice contains its distinct business logic and persistent data storage. The various services interface with each other via Application Programming Interfaces (APIs) and lightweight protocols like REST, enabling loose coupling between the modules.
Microservices architectures provide numerous benefits:
- Modularity – services can be developed, tested, and deployed independently
- Flexibility – services can use different languages and technology stacks
- Scalability – services can be scaled as needed rather than the entire monolith
- Agility – smaller codebases enable faster development and easier changes
- Resilience – failures are isolated rather than impacting everything
However, microservices also introduce complexity:
- Distribution – must manage many separate components
- Testing and debugging across services
- Inter-service communication with APIs
- Operational overhead of operating many services
So microservices trade simplicity for flexibility. PMs must weigh the pros and cons when considering architectures.
Benefits of Microservices
Microservices provide several advantages over traditional monolithic architectures:
Modularity – Microservices are highly modular, allowing different services to be developed, tested, and deployed independently. This makes development faster and enables better organizational alignment.
Independent scaling – With monoliths, you need to scale the entire application even when only a specific module is bottlenecked. Microservices allow scaling each service independently.
Technology flexibility – Microservices don’t require using the same technology stack. Different languages, frameworks, and data stores can be used for each service.
Faster release cycles – Modular services can be updated frequently without rebuilding the entire monolith each time. This facilitates continuous delivery.
Better resilience – If one microservice fails, it doesn’t break the entire system. Failures are isolated to specific services.
Microservices enable smaller development teams to work autonomously on different parts of the application. This results in faster development velocity long term.
Drawbacks of Microservices
However, microservices also come with some downsides:
Complexity – A microservices ecosystem with many different services is inherently more complex to build and manage.
Testing and debugging – With business logic distributed, testing and debugging are harder across different services.
Operational overhead – Deploying and operating many different services introduces overhead.
Integration challenges – Connecting services via APIs/messaging brings complexity.
No silver bullet – Microservices might be overkill for small, simple applications.
There is added complexity of distributed systems. So microservices may not make sense in the early stages of an application but become beneficial as the product and team scale up.
The distributed nature of microservices also makes robust monitoring and logging essential. Product managers should ensure this is built into the architecture.
Overall, microservices provide powerful benefits but also incur costs. PMs should carefully evaluate if the increased complexity is worth it.
Microservices Use Cases
Microservices architectures make sense for large, complex applications and software built and maintained by sizable teams. The modular approach facilitates agile development and continuous delivery by breaking work into independent components.
Some examples where microservices excel:
- Large enterprise applications with diverse functionality
- Consumer web/mobile apps requiring frequent updates
- Platforms needing to scale rapidly and independently
- Teams with many developers working in parallel
- Software built around APIs and microservices from the start
Many tech giants like Amazon, Netflix, Uber, and PayPal leverage microservices to rapidly build, deploy, and scale applications. The flexibility enables them to experiment and innovate quickly.
However, microservices may be over-engineering for smaller apps. The overhead can slow down development compared to a monolith. Companies like Facebook and Twitter found starting with a monolith effective early on before migrating to microservices.
So microservices work best for sizable, complex software systems and products being built by large, distributed teams. The productivity gains outweigh the costs at a substantial scale.
Key Differences and Considerations
Some key differences between monolithic and microservices architectures:
| Monolithic | Microservices |
| Single unified application | A suite of modular, independent services |
| Tightly coupled modules | Loosely coupled, distributed components |
| Shared technology stack | Can mix languages and data stores |
| Scale the entire app together | Scale services independently |
| Easier to develop and test | Increased complexity to develop and test |
| Simpler ops and monitoring | More ops overhead across services |
| Faster initial dev velocity | Agile, continuous delivery at scale |
When choosing between the two architectures, factors to consider include team size, release velocity needs, application complexity, required scalability, and rate of change.
Monoliths make sense for smaller teams and simple use cases. Microservices are better for large, complex apps and continuously delivered software where agility trumps simplicity.
By understanding the capabilities and limitations of each model, product managers can work more effectively with technical teams in determining the optimal architectural style.
How Understanding Monoliths and Microservices Helps Product Managers
Grasping monolithic versus microservices architectures allows product managers to make more informed decisions and have meaningful discussions with engineers. Here are some key ways it helps Product Managers:
- Enables better planning and prioritization – Knowing how architectures impact velocity and change absorption means PMs can plan more realistic roadmaps and prioritize appropriately.
- Drives technology selection – Understanding architectural trade-offs helps guide choices on language, frameworks, infrastructure, etc. based on project needs.
- Aids communication with engineers – Being conversant in architectures makes collaboration with technical teams more effective.
- Informs scaling, performance, and availability needs – Architectures influence how systems are scaled, monitored, and made resilient.
- Impacts team structure – Monoliths allow smaller teams while microservices work better with larger distributed squads.
- Determines release frequency – Microservices support continuous delivery better than monolithic systems.
In summary, architecture is a foundational aspect of software delivery that impacts project management, planning, technical execution, and product evolution. While Product Managers don’t need to be architects, grasping core models is crucial.
Architectural Transitions
Most companies begin with monolithic architectures and then migrate to microservices over time as complexity increases. Planning this transition is key.
Strategies for incrementally moving from monolith to microservices:
- Strangling the monolith – Build new functionality as microservices, and leave the legacy monolith intact.
- Selectively refactoring subsystems – Extract modules like payments or messaging into standalone services.
- Splitting UI layer – Build a new presentation layer while the backend remains monolithic.
- Prefer microservices for non-core features – Add ancillary capabilities as services first.
- Establish well-defined service boundaries – Avoid tight coupling between microservices.
- Put guardrails in place before transitioning – Don’t prematurely microservice everything.
Migrating from monolith to microservices takes time. PMs should expect a transitional dip in velocity as complexity increases before gains materialize. Careful planning and solid service boundaries are essential.
Best Practices for PMs Working with Architects
Here are some tips for product managers to collaborate effectively with architects and engineers on application architecture:
- Participate in architectural reviews – Contribute user perspective and requirements considerations while architects explore technical options.
- Understand priorities and trade-offs – Architectural decisions involve balances between complexity, velocity, scalability, etc.
- Provide usage forecasts – Estimated traffic, scale, and growth help guide infrastructure decisions.
- Align architecture to business goals – Ensure technical style matches desired agility, time-to-market, TCO, etc.
- Guide appropriate architectural decisions for new features – Influence modular vs monolithic design for new capabilities.
- Anticipate change – What parts of the system are most likely to evolve rapidly? Where is flexibility needed?
- Consider architecture impacts on timeline – Factor in development complexity, testing needs, and velocity.
- Validate architectural direction with stakeholders – Ensure executives understand the implications of architectural choices.
- Participate in proof-of-concepts – Hands-on exploration of new technologies or architectural patterns.
By partnering closely and sharing insights, PMs and architects can determine optimal technical solutions together.
Monoliths and Microservices: Key Takeaways
- Monolithic and microservices are two fundamental software architectures that Product Managers should grasp.
- Monoliths provide simplicity while microservices offer increased modularity and agility.
- Monoliths make sense for smaller teams and apps, while microservices empower large distributed teams.
- Microservices enable continuous delivery and independent scaling but add complexity.
- Understanding architecture trade-offs helps Product Managers plan roadmaps, prioritize, and collaborate with engineers.
- Most companies start with monoliths and incrementally transition to microservices over time.
- Architectural decisions have far-reaching impacts on product development and iteration that Product Managers must consider.
By comprehending architectural styles, product managers can make smarter product decisions and lead technical teams more effectively.
