Before building a house, the architect makes a drawing that describes the building area, premises, communications, lighting, etc. A well-designed project is almost 100% a guarantee of a successful result. It considers all the nuances paying particular attention to the client’s needs. When the project is finished, the builders enter upon the implementation. They lay the foundation, build walls, poot roof, and do the interior decoration. Following the defined plan, they avoid annoying mistakes and quickly achieve the goal.
If we translate all the above into app development, it won’t be any different. The right app architecture gives a good start and acts as a skeleton that will be further expanded with muscles and skin. This post will talk about different software architectures and advise on choosing the best one for your enterprise app.
What Is App Architecture?
In short, app architecture is a collection of methods and patterns that helps create well-structured apps. The architecture requires developers to make critical decisions about the organization of the software system and includes:
- selecting structural elements and their interfaces that compose the entire system
- linking selected elements and building a more extensive system
- creating an architectural style that guides the organization as a whole
App architecture depends on many factors:
- The target audience
- Feature set
- Team skills
When you create typical personas, you understand which devices are your priority. Further, you can decide on the features set and agree on the app development timeline. Of course, a team of professionals will deliver the product faster and better, so pay enough attention to the contractor’s choice.
In this article, we will skip the step of creating personas and describing features. Instead, we will focus on different app architectures for big projects. The next section will explain them in detail.
As the name suggests, such app architecture consists of several layers or tiers. The number of layers depends on the app specifics and is selected individually for a project. Each layer unites similar elements and interacts with two neighboring layers. The last or lowest layer is usually the database. Therefore, requests to it pass through all tiers that are connected in sequence.
Developers often choose multitier architecture for ease of use and many frameworks. Although the layers are linked, they are still autonomous units. So, if you need to change something in one layer, it will not affect the rest. Imagine, for example, that you want to replace MySQL with Cassandra DB. You will have to do a lot of work in the database layer, but this will not affect the other app components in any way.
On the other hand, handling layered apps may be challenging if you work with a big project. Even though the tiers are independent, the app runs as a single system when it is installed. If you need to adjust something in one particular layer, all the app components will have to be revised. Besides, multitier architecture is not the best choice for fast-growing projects because it is hardly scalable.
When to use
Multitier architecture is a tried-and-true option with a great many tools. Developers often choose it for fast and error-free implementation. The layered structure may be the right pick for specific departments’ apps, e.g., accounting, marketing, and sales. Such apps usually have a defined set of features and rarely require scaling up.
The event-driven pattern works on the event-response principle. An event is an action that initiates either some notification or a change in the app state. For example, if a new user creates an account, it is a notification, and if the user edits their address, it is a state change. Note that not all events should be added to the event-driven solution. Only business-relevant events matter in the app architecture. For instance, the event “user places an order” is important from a business point of view, but “user eats ordered pizza” is not.
This architecture is good for its efficient use of app resources. In this case, not the entire system is involved in events processing, but only specific modules. Moreover, the event producer determines the event’s urgency and puts them in a query, so the system works with maximum performance. Another advantage is easy scalability due to the multi-module app system. This makes event-driven architecture a perfect match for large and small projects.
The weak side may be a relatively slow operational speed if the system processes events as and when they are received. Also, it may be tough to debug if many modules take part in the event handling.
When to use
Developers often opt for an event-driven architecture when working on apps that instantly process multiple requests. These are mainly streaming services that scale tasks on demand. This architecture design pattern is also great for IoT apps, where you have to include hardware into the events processing model.
This type of architecture consists of two components: the system kernel and plugins. Plugins are responsible for the business logic, and the kernel manages their loading and unloading. What is the purpose of such an app architecture? First of all, maximum customization and increased productivity. Imagine using a tool for time management like Jira or Trello. For small companies, a basic set of functions may be sufficient, while large corporations may want to add extra modules, for example, departments-based. In this case, the microkernel pattern is ideal because it meets different needs and does not overload the user with unnecessary features.
The microkernel-based apps are very flexible and adjustable. You can adapt them for any business goals and safely debug the plugged-in modules without touching the app kernel. Corporations benefit from such software because it always works at peak efficiency. Thus, organizations face minimum downtime and bear the smallest losses. Besides, they can scale software as the business grows or decreases.
App performance may go down if you plug in too many modules. Yet, it may be problematic to find the right balance between the number of plugins and microkernel tasks. It is also challenging to set in advance (before app development starts) the optimal microkernel code fragmentation degree. Later, it is almost impossible to change the chosen approach.
When to use
Microkernel architecture is excellent for scalable apps with many users and apps with a clear separation of base methods and high-level rules. It will serve well the systems with dynamically changing rules that need to be updated frequently.
The microservice-based app consists of many independent parts (microservices), each responsible for a specific task. The services can be written in various programming languages because they interact using REST APIs (for example, using JSON or Thrift). Symmetric app architecture sets peer-to-peer dependencies excluding hierarchical connections.
Usually, it takes no more than two weeks to create one microservice. Such timeframe is optional yet optimized for writing lightweight code that is easy to read and modify.
The foremost benefit is perfect scalability, which is essential for enterprise apps. If you want to add a new function, it is enough to write a new service. If the feature is no longer needed, the microservice can be disabled. Each microservice is a separate project, so it is easy to distribute work between development teams.
It is difficult to spot mistakes. You have to dig through tons of logs to detect the “guilty” process and find out why the request wasn’t completed. This results in overhead costs when passing messages among microservices. According to our estimates, the growth of network costs can reach 25%.
When to use
Microservice architecture is the number one choice for extensive apps with high loads, such as chats or call-centers. You can quickly scale them by adapting to load changes. Also, it is good for fintech apps that require high security. The matter is that microservices are isolated and communicate via API, so you can be sure the only data needed for a particular service will be transmitted.
Why We Choose Microservices At Softensy
At Softensy, we specialize in enterprise-level apps. We develop financial services, CRM/BPM solutions, real estate, and smart farming apps. Currently, our main project is mobile banking for a large European bank. The app runs on iOS and Android and has over a million downloads. The project is continually growing and gaining new features. That is why we develop it based on a microservice architecture because it allows us to add, edit, or remove certain functionality quickly.
On top of that, this approach allows us to use diverse technologies and select the most efficient tech stack for particular services. For example, the microservice, which is in charge of push notifications and SMS, is written in Go, the internal app for bank employees runs on Flutter, and the basic app functionality is coded with Kotlin and Swift.
Another argument for microservices is cloud infrastructure. We recently entered into a partnership with Amazon and ultimately migrated the project to AWS. The cloud/microservice union has allowed us to achieve the maximum performance and scalability effect. We reduced downtime and made the app work equally well during regular and peak times.
Summing up the above, we believe that microservice architecture is the best choice for large-scale projects. It allows you to adapt quickly to business needs and work at top efficiency. Anyhow, each project has unique nature with different goals and users. It is crucial to set the right tone from the very beginning to get a great result. If you have a fresh idea to launch an app or want to refactor the existing project, get in touch for expert advice.