Best Practices for Microservices in FinTech

Microservices fundamentally changed the way applications are built, managed, and supported after launch. Even more – they had changed the way engineers and managers think about digital products in the first place. The idea behind them is very simple – let’s make something scalable to power a fast-paced market and the need for constant change. Easy to say, harder to do. That’s why we have gathered some best practices for microservices. They will help you build a great FinTech product and manage its growth.

Main patterns and general best practices

Before we dive a little deeper, let’s talk about what microservice architecture is and how it can be of… well, service. In a nutshell, microservices are a way to structure a product’s code in a way that boosts the product’s performance. Thanks to the model of architecture, it’s also much easier to introduce new modules and even entire technologies to an already existing code.

Microservices are nothing more than a group of interconnected, yet independently working frameworks, tools, and libraries designed to run their respective tasks. They also cooperate to form added value. They are:

• written with the use of different languages to support business logic

• build within small, multidisciplinary teams

• easy to deploy

• easy to test and maintain

The best way to approach development is to know what you want to do. The business justification for product development is always the most important guidance. When you know what needs will the product fulfill and what are market expectations towards it, everything will be easier. 

The second step would be to understand that microservices require a non-standard approach. Or rather, a new standard, since small and entirely autonomous teams are nothing new in the industry. Full-stack teams should take ownership of the entire process of software development and be responsible for every step of the way. Every team should have full domain authority and knowledge. It should have specialists to cover the development of the user interface (UI), business logic, and data layer. These are the necessary building blocks.

The third step is called turnover management. People will leave the team, for whatever reason. They can get sick, move, change their role in the team or within a company. They can be also rejected by the client; it happens when you deal with a third-party vendor. It’s very important to find someone who can easily fill the shoes and pick up the slack. 

Not also when it comes to software development per se, but also when we talk about the widely understood business layer. Areas like AWS consulting, for example, are not easy things to do. Not every developer can perform on a certain level and have the necessary knowledge to help you. The need for quality replacement and turnover management is a very important aspect.

Best microservice practices

Some of the tips you’ll see below are low-level. That means a commitment on your part. A hands-on approach when implementing them will only benefit your organization, not to mention the product itself.  

1.         Ensure the availability of a dedicated infrastructure. Issues like load balancing, caching, performance, monitoring, and apps’ security are so vital, that development starts before a single line of code gets even written. You have to make sure that hosting or quality cloud computing services are in place. To handle the load and the traffic but also to simply make the product work. Without unnecessary hiccups.

2.         If you migrate a monolithic app, do it slowly. The thing about microservices is that they’re complicated. They can incredibly boost the app but first, they must be applied with knowledge and care. Monolithic architecture does not compute with microservices. Migration should be done slowly and with business justification in mind. What do you want from a new architecture? How can it power your business goals? What legacy functionalities do you want to introduce in a new product? Figure out the basics and go from there. 

3.         Rest with RESTful APIs. You don’t have to install anything on the client-side. Also, you don’t need software development kits (SDKs) or even frameworks. Also, RESTful APIs are very flexible and portable. That gives you, for example, the ability to migrate from one server to another and carry out changes on a database with ease.

4.         Make “loosely coupled principle” a priority. In the world of microservices, there’s a term called “a single responsibility principle”. One microservice is created to do… well, just one thing. By doing so, it’s easy to maintain, test, and rescue after a fault. The loosely coupled principle is healthy because if something goes down, only one functionality suffers. Not the entire application, which is unfortunately true for the monolith. 

5.         Take care of security issues. The matter of application security is one of the best known, not only among FinTech, which falls into many categories of state regulation. That’s why it’s best to tackle the topic early on. Adopt the DevOps model to ensure the security of the entire framework. Because the nature of microservice patterns and best practices are vastly different than what’s in store for the monolith, DevOps is the best tool. 

6.         Design and implement a discovery mechanism. With a monolith, you get one solid product. That’s it. With microservices, you have many micro products that work independently and together at the same time, to form one big structure. That’s why it’s so important to design a mechanism helping services to find and talk to each other. A single source of truth for that is called the “service registry”. There are two methods to get this done: self-registration and external monitoring. Both keep services in check. But that’s not all. You also need to make sure microservices find themselves dynamically. For that, you need smart servers or smart clients. Alternatively, for a simplified approach, you may use load balancers and DNS.

7.         Implement service templates. Microservices need to perform their basic business logic. Execute commands, monitor application status, reroute communication, display messages to the user, manage loads, etc. On the other hand, service templates speed up these processes. Another thing is the availability of cross-team code reviews, which is very useful for developers. 

8.         Introduce centralized logging. A system for centralized logging should be provided to the services by the system. All should submit their logs to the same location in one, standardized log format. This enables developers to quickly spot bugs and search for queries in one location. 

9.         Remember about containers. With containers, you can deploy and manage services independently. You won’t affect services hosted on other containers, which boost an already flexible architecture. With containers, you have interoperability and platform independence.

10.      Keep in mind open-source tools and their dependencies. Developers like to use open-source tools for things like monitoring, security, logging, or debugging. Open-source tools are very useful but they also bring concerns related to the safety of the entire architecture. The way to deal with that? Establish repositories for previously approved versions of the software. Verify and trust open-source authors and vendors as well as set up governance for exceptions.

11.      Make sure your API changes are backward compatible. Adopt contract testing for your APIs and integrate these contracts tests as part of your builds. This will prevent unlawful changes.

12.      Keep code at a similar level of maturity. It’s called the “immutable infrastructure principle”. In a nutshell – make sure all microservices are at a similar level of development and none of them lags in quality, overall maturity, and stability. If you need to replace some of the code deployed in any given microservice that performs well, a good approach is to create a new microservice with this new or changed code. Then you leave an already existing service in its place. In this approach, you can safely test new code until it’s free of bugs, without “infecting” a good microservice with faults.

When things get complicated, simplify them!

Microservices are great for many different reasons. They can be hard to implement but when you get your head around it, you can be sure life will be a lot easier. If you can’t do it alone, find the team that can do it for you. Microservices are building blocks of modern digital products and ecosystems. They are not a remedy for everything but don’t be discouraged by this fact. Don’t miss out on the opportunity!