Microservices or monolith? The debate continues in 2026

For years, adopting microservices has been presented as an almost natural evolution for applications that needed to grow. Dividing a platform into independent services promised greater scalability, faster deployments, and teams capable of working with greater autonomy.

In 2026, the architectural decision requires more context. Microservices continue to be a solid option for certain systems, but the accumulated experience with distributed architectures has made their operational cost more visible. At the same time, the modular monolith offers an alternative to keep an application within a single deployment unit without giving up clear boundaries between domains.

The choice affects development, infrastructure, data, testing, observability, and team organization. Therefore, deciding between a monolith and microservices should start with the characteristics of the product and the organization that will have to operate it.

Monolith and microservices solve modularity differently

A monolithic architecture packages different functionalities within a single deployable application. This simplifies certain operations because much of the communication occurs within the same process, and components can share infrastructure and persistence mechanisms.

The risk arises when internal boundaries begin to disappear. Modules that directly access components from other areas, business logic distributed throughout the code, and hard-to-identify dependencies can turn every modification into a change with unpredictable impact.

Microservices shift some of those boundaries to the infrastructure. Different capabilities run as independent services and communicate through defined contracts, usually APIs or messaging.

This separation can facilitate independent deployments and scaling, but it also turns problems that previously occurred within a process into issues typical of a distributed system.

A good Software Architecture needs to evaluate both sides of that equation.

The modular monolith introduces a third alternative

Comparing only a large, tightly coupled monolith with an architecture of dozens of microservices leaves out an important option: the modular monolith.

In this approach, the application continues to be deployed as a unit, but internally it is divided into modules with controlled responsibilities and dependencies. Each module can represent a capability or domain and expose specific interfaces to the rest of the application.

The goal is to gain some of the discipline associated with service boundaries without immediately assuming the operational complexity of a distributed architecture.

This feature can also facilitate future evolution. When a module develops scalability, availability, or autonomy requirements different from the rest of the application, its boundaries are already better defined to evaluate a possible extraction.

What microservices really bring

The main value of a microservices architecture appears when the independence between components addresses real needs.

A service can be deployed without redeploying the entire application. It can also scale independently when its load pattern differs significantly from the rest of the system.

This autonomy can extend to teams. When a domain has clear boundaries, a team can take responsibility for its code, deployment, and operation, reducing certain organizational dependencies.

Backend Developers can work on services with defined contracts while other teams develop different components of the platform.

There is also a potential advantage in fault isolation. If the architecture is designed correctly, a problem in one service can be contained without necessarily causing the entire system to fail.

However, achieving these advantages requires that the services be sufficiently independent. Separating code into multiple repositories or containers does not guarantee decoupling.

Distributing an application introduces new problems

An internal call within a monolith is usually fast and predictable. When two capabilities become separate services, that interaction crosses a network.

From that moment, latency, timeouts, retries, temporary loss of connectivity, and partial failures can arise.

The system needs to decide what to do when one service responds and another does not. It must also prevent a failure from generating retry chains that can further increase the load.

Complexity also appears in the data. An operation that could previously be executed within a single transaction may need to coordinate changes between different services and information stores.

Concepts like eventual consistency, idempotence, sagas, and messaging then cease to be secondary decisions and become part of the design.

Observability and debugging are also distributed

Investigating an error within a monolithic application may require following logs and execution within the same environment.

In microservices, a request can traverse several components before producing a response. Identifying where a problem started requires correlating information between services.

Centralized logs, metrics, distributed tracing, correlation IDs, and alerts become part of the operational platform.

DevOps Engineers gain special relevance in this scenario because CI/CD, observability, and automation need to support a larger number of deployable components.

The modular monolith avoids distributing complexity too soon

A product that is still discovering its domain boundaries may struggle to correctly define its future services.

An incorrect separation generates frequent dependencies between components. If a new feature requires simultaneously modifying four services, coordinating four deployments, and maintaining compatibility between several APIs, part of the independence that justified the architecture disappears.

Within a modular monolith, moving responsibilities between modules is generally less costly because the boundaries are not yet conditioned by remote communication, independent infrastructure, and contracts deployed in production.

This can be especially useful during the early stages of a product when the domain is changing rapidly.

A team of Full Stack Developers can maintain high speed working on a modular application without immediately assuming a distributed platform that the product's volume does not yet justify.

Discipline remains necessary. A modular monolith loses much of its advantages when any module can directly access any internal component.

The distributed monolith combines costs without achieving autonomy

One of the most problematic scenarios arises when an application is physically divided into services but retains a high level of dependency between them.

A service needs to know the internal structures of another, several components directly share the same database, or practically every release requires coordinating changes in multiple services.

The architecture is distributed from an operational point of view but continues to behave as a single unit from a development perspective.

This is often described as a distributed monolith.

The organization then assumes much of the cost of microservices — network, multiple deployments, distributed observability, and coordination — without achieving sufficient independence.

The most common signals include:

• seemingly small changes that require modifying several services;

• releases that must be coordinated between different teams;

• multiple services writing directly to the same tables;

• long chains of synchronous calls to complete basic operations;

• failures in one service causing successive errors in other components;

• difficulties in identifying which team has real ownership over a process.

Under these conditions, creating even more services can increase complexity without correcting the root of the problem. Reviewing domain boundaries and dependencies often adds more value than continuing to fragment the application.

When do microservices start to make sense?

The scale of users alone does not determine the architecture. A system can manage a considerable load within a well-designed monolithic application deployed on scalable infrastructure.

Microservices become particularly interesting when different parts of the system develop clearly distinct needs.

A component may need to scale much faster than others. A domain may require an independent release cycle. Certain services may need specific availability or isolation requirements. There may also be a large enough organization for several teams to need to work and deploy autonomously.

In these scenarios, distributing the architecture can address existing limitations rather than anticipating hypothetical problems.

Cloud Engineers can design the necessary infrastructure to support that model, but the availability of Kubernetes, containers, or managed Cloud services does not in itself constitute a reason to adopt microservices.

The infrastructure must respond to the architecture, and the architecture to the needs of the product.

Traditional monolith, modular monolith, or microservices

All three alternatives can be valid depending on the context. The difference lies in how much isolation the application really needs and how much operational cost the organization can bear.

The table shows why the modular monolith occupies an interesting position. It maintains a relatively simple operation while forcing work on architectural boundaries that can facilitate future evolution.

The organization is also part of the architecture

Technical architecture and team structure end up influencing each other.

An organization with three or four developers probably gains little benefit from maintaining twenty independent services. The same people will have to modify, deploy, and operate practically all of them.

When there are numerous teams working on different domains, the situation changes. Service boundaries can provide ownership and reduce the need to coordinate every modification within a shared codebase.

Before adopting microservices, it is advisable to review four conditions:

• whether there are sufficiently clear domains to establish stable boundaries;

• whether different components need distinct deployment or scaling cycles;

• whether teams can take operational ownership of their services;

• whether the platform has sufficient automation and observability to operate a distributed system.

The absence of these capabilities can turn the architecture into an additional source of work for the same team that was trying to gain speed.

Migrating from a monolith to microservices does not require rebuilding everything

When an existing application begins to encounter limitations, the transformation can be carried out progressively.

The Strangler Fig Pattern allows for extracting certain capabilities while the rest continues to function within the monolith. In this way, the organization can start with the domains where independence produces a concrete benefit.

A module with particular scalability needs can become one of the first candidates. The same can happen with a capability maintained by an independent team or with a component whose deployment cycle is slowing down the rest of the application.

This approach allows checking whether the organization can operate the first services correctly before extending the model.

It also avoids a massive migration whose return may take years to materialize.

The IT infrastructure must evolve in parallel to support automation, observability, networking, security, and operational continuity as the number of components increases.

The right architecture introduces the complexity that can be justified

The debate between microservices and monolith continues in 2026 because neither architecture alone solves software design problems.

A poorly structured monolith can become a difficult application to modify and deploy. A poorly designed microservices architecture can transfer that same coupling to the network and add a considerable layer of operational complexity.

The modular monolith offers a particularly useful alternative when the product needs clear boundaries but does not yet require physical independence between its components. Microservices make more sense when specific needs for autonomy, scalability, isolation, or ownership between teams arise.

The decision should arise from those conditions and be reviewed as the system evolves.

An architecture designed today does not need to become a permanent decision. Maintaining good boundaries between domains allows starting with a simpler structure and distributing components when the product's growth justifies the cost.

In 2026, architectural maturity also means knowing when not to add complexity.