Krzysztof is our Head of Products and he leads the technical development behind the suite of our ready-made solutions. Throughout the years in Solidstudio, he gained an invaluable insight into the eMobilty industry’s requirements and is now more than qualified to share his knowledge with others.

Krzysztof Ciombor

While not as revolutionary as some other programming languages, 

 has been steadily growing in popularity over the past couple of years.

The initial spike on May 17, 2017, was caused by the Google Android team 

Of course, this shouldn’t be at all surprising that the majority of Kotlin development is done for 

. Official docs encourage Kotlin usage and most SDK docs offer snippets of code in Kotlin making it very easy to get started. Growing popularity on StackOverflow means that it’s sometimes easier to find the answer to your question in Kotlin than in Java.

Many big companies already switched their development to Kotlin and are amazed by the results. Big names on this list include Google and JetBrains themselves, Amazon, Netflix, Coursera and, Uber, but many smaller companies are also making the switch.

https://firebase.google.com/docs/firestore/query-data/get-data#kotlin+ktx

https://developer.android.com/kotlin/stories

https://medium.com/@daveford/who-is-using-kotlin-84b11b4fb51a

Android development is not the only thing we can do in Kotlin though. By leveraging Kotlin Multiplatform Mobile capabilities we can create a re-usable domain logic code that can be shared between mobile apps on Android and iOS. Even though this project is still in the alpha phase, some big companies are already experimenting with this technology and the results are promising. The premise of sharing business logic between multiple platforms is very appealing both in terms of development speed as well as maintenance costs. This was clearly visible in the recent shift towards cross-platform frameworks like React Native or Flutter, but it should soon be possible to 

https://blog.jetbrains.com/kotlin/2020/08/kotlin-multiplatform-mobile-goes-alpha/

Web development is basically all JavaScript, but that does not mean other languages cannot be used for this purpose. Languages like Typescript, Elm, Clojurescript, or ReasonML are all used in Web development by transpiling them back to JavaScript. Using Kotlin/JS we can do the same with Kotlin! If you don’t want to abandon your current knowledge about React, Redux, React Router, or even styled-components, take a look at the kotlin-wrappers repository which provides wrappers for all those libraries and more.

Kotlin/JS gives you all the benefits of Kotlin while still allowing you to interact with DOM or use npm packages directly inside Kotlin code.

Remember Kotlin Multiplatform? It works for Kotlin/JS as well, which means the business logic can be shared between Android, iOS AND web version of your app!

https://kotlinlang.org/docs/reference/js-overview.html

https://kotlinlang.org/docs/tutorials/javascript/setting-up.html

By this point, you may be thinking that Kotlin is perfect for front-end parts. Turns out it is pretty nice on the backend side as well. If you’re already familiar with the usual 

 backend stack which uses Spring Boot it is very easy to make the switch to Kotlin and it’s now easier than ever to write Kotlin-idiomatic code in Spring Boot.

If you’re searching for a lightweight server-side framework in Kotlin, 

 is gaining more and more traction within the community.

Going all-in on Kotlin? By using multiplatform capabilities, one can easily create a full-stack application and share business logic between all frontends and backend (for things like validation logic, shared models, etc)

https://spring.io/guides/tutorials/spring-boot-kotlin/

https://blog.jetbrains.com/kotlin/2020/08/the-state-of-kotlin-support-in-spring/

https://github.com/Kotlin/kotlin-full-stack-application-demo

Sometimes we cannot, or don’t want to, use a virtual machine (JVM), for example when targeting embedded devices. That’s where Kotlin/Native comes into play.

Not only can it produce native Windows, Linux or MacOS binaries but it can even support iOS, watchOS, tvOS, and WebAssembly. It is easy to include compiled Kotlin code directly in an existing C/C++ project as well as call native code directly from Kotlin/Native.

https://kotlinlang.org/docs/reference/native-overview.html

https://www.bignerdranch.com/blog/exploring-kotlin-native-part-1/

Although Python is still very much dominating the data science scene, Kotlin is making its appearance here as well. If you want to leverage JVM capabilities and performance while writing concise, statically typed and null-safe code, Kotlin may be a perfect fit for you. Afraid of losing your favorite tooling? Don’t be! Kotlin kernel for Jupyter Notebook and Kotlin interpreter for Apache Zeppelin will let you do the exploratory research and data visualization within those interactive editors. Want to jump straight into deep learning? Being fully interoperation with Java libraries, Kotlin can integrate seamlessly with existing open-source projects like 

https://kotlinlang.org/docs/reference/data-science-overview.html

As we can see, Kotlin can be used for a wide variety of subjects, starting with Android development and ending among native binaries. Be aware, as some of those technologies like Kotlin Multiplatform and Kotlin/Native are still quite new and can be rough around the edges, but this wide spectrum of Kotlin capabilities shows that there is a real interest in such a versatile programming language. Both the team behind Kotlin and the community are working very hard to make this vision a reality.

Since it is very easy to integrate Kotlin with Java, if you already have a Java project (maybe an Android app or a backend service), don’t be afraid to give Kotlin a try. Who knows, maybe this time it will save you from the 

Not convinced? Feel free to reach out, and we will help you make the switch to Kotlin.

A quick overview of Kotlin framework. Click to read the whole article.

Our rank of the best JavaScript frameworks which you can use in 2020.

Being an eMobility leader in various projects across multiple startups, Piotr was responsible for OCPI and OCPP integration as well as EMP and CPO platforms development. With extensive expertise in the open standards field and eMobility tech solutions, he is leading teams of experienced developers and contributing with invaluable knowledge and experience.

Piotr Majcher

According to the Stack Overflow Developer Survey, JavaScript is the most commonly used programming language – for the seventh year in a row! There's no denying that JavaScript is the go-to technology choice for any web development project. The greatest advantage of JavaScript lies in its rich ecosystem of tools, libraries, and frameworks. New JavaScript frameworks emerge on a regular basis, helping to make the language more accessible and easier to use for software developers.

However, the profusion of tools also makes choosing the best-suited framework for the job a challenge. What are the most popular JavaScript frameworks in 2021? And what factors should developers take into account when choosing the technologies for their projects?

Read this article to get an overview of the best JavaScript frameworks on the market and their defining characteristics.

earned considerable popularity very quickly – it's the fastest-growing JavaScript framework today. Developers use this handy library to build and operate dynamic User Interfaces of websites that experience high traffic. That's why it's such a great technology fit for enterprise-grade applications. High-traffic platforms like Facebook and Instagram use React to support their UIs.

is widespread open-source framework companies use primarily for developing dynamic single-page web applications (SPA). Companies like PayPal, Freelancer, and LinkedIn use the framework for powering their UIs.

What's the key strategic advantage of using Angular in a project? It's one of the most powerful and efficient JavaScript frameworks on the tech scene. Its component-based architecture provides a high quality of code, and the use of TypeScript helps developers to write clean code and scale applications easily. The long-term support of Angular by Google is a mark of its quality – but it also means that the framework has a bright future ahead of it.

Since developers get to work with independent libraries, React is more flexible than Angular – and it offers comparatively better response time. All in all, the technology is an excellent pick for applications that need to deliver optimal performance under significant traffic pressure.

Vue was developed in 2014 and is currently used by giants such as Baidu, Grammarly, WizzAir, Facebook, and Buzzfeed. Vue is a great pick for building single-page applications, but it can also support more complex projects and deliver optimal performance.

The framework is known for its accessibility – it's a perfect starting point for developers who want to learn a new framework quickly. Since it goes back to its JavaScript roots, it's also very convenient to use – accelerating the development process and allowing teams to deliver value faster.

Vue is surrounded by an active community of developers who are happy to share their knowledge. The framework also offers detailed documentation that flattens the learning curve for developers who are Vue newbies.

Ember was developed in 2015 and since then has taken the tech scene by storm. The undeniable strength of this framework lies in the fact that it supports two-way data binding that allows developing a reliable platform for handling complex User Interfaces. Companies like LinkedIn, Netflix, and Nordstrom use Ember to build their websites.

The open-source framework is an excellent technology for single-page applications, but also large, complex web apps. However, Ember is known for being a highly opinionated framework – it makes many assumptions about the application and requires developers to conform to these expectations.

Meteor comes in handy to both frontend and backend developers, covering a major portion of software development. This open-source, full-stack framework provides support in a wide range of tasks, from database management and backend development to business logic and frontend rendering. Meteor was written using Node.js, so it allows creating cross-platform code and supports rapid prototyping. It easily integrates with other frameworks such as React, Angular, or Express. It allows developers to build hybrid applications using JavaScript, CSS, and HTML. All in all, Meteor boosts the productivity of development teams by helping developers write less code. Companies like Qualcomm, Honeywell, Mazda use Meteor to build applications.

s is a server-side JavaScript run-time environment that enables development teams to carry out cross-platform projects to help them save time. One of the most frequently downloaded frameworks, Node is an open-source technology used for building backend services or APIs and developing server-side networking applications. Node is built on top of Google Chrome's JavaScript Engine (V8 Engine).

Node can handle multiple requests asynchronously thanks to a non-blocking single-threaded event loop – that's why it works so well for distributed systems that involve numerous network requests. Used by companies like Uber, PayPal, and Walmart, Node helps developers all over the world to boost the performance of their apps while writing fewer lines of code.

This framework is a collection of open-source modern JavaScript modules. Development teams can use it to implement any sort of interface – it comes in handy, especially for more robust websites. Aurelia is able to extend the HTML for various purposes – for example, data binding.

The framework offers a robust platform for building browser, desktop, and various mobile applications. Companies like Freska, Ordami, and BTEK Software use Aurelia in their projects. This is the only framework that allows developers to build components using TypeScript or JavaScript.

This client-side JavaScript framework is mainly used for developing single-page applications. It's easy to implement, small (< 8kb gzip), fast, and provides plenty of useful features out of the box.

Currently used by companies like Nike and Fitbit – as well as open-source platforms like Lichess – Mithril uses a sophisticated virtual DOM algorithm to minimize the number of updates and accelerate the development process and ensure high performance. It has a gentle learning curve that allows software developers to start using the framework after spending very little time learning about it.

Polymer is an open-source JavaScript library developed by Google. Development teams can use it to create various website elements without having to get into the complex level. Polymer supports both one-way and two-way data binding. That's why it can be applied to solve many different problems.

The framework has gained considerable traction on the market because it provides a structured design process. Polymer was built to take advantage of the features present in the web platform to allow developers to build components easily. It was the first library to enable interactive building applications by composing components. Many Google services and sites use Polymer – for example, YouTube and Google Play Music. Netflix benefits from Polymer as well.

Used by companies such as Sony Entertainment Network, Airbnb, and SoundCloud, Backbone is one of the most famous JavaScript frameworks. It has a gentle learning curve, and developers have an easy time understanding it. You can use it to create single-page applications and client-side applications that run in a web browser. The idea behind the framework was keeping all the server-side functions flowing through an API – that's how teams can build complex functionalities by writing less code. This lightweight library is highly flexible and allows developers to choose the right tools for a specific project.

Which is the best JavaScript framework for my project?

JavaScript frameworks bring many benefits to the development process by making it easier for developers to work with JavaScript. When choosing the framework for your project, pay attention to the level of complexity it can handle and key problems it promises to solve. If you're looking for a technology that would enable your team to bring a product to market fast, choose a framework known for accelerating the development process.

Are you looking for JavaScript experts who could help you pick the best technologies for your project? Get in touch with us; we have a lot of experience working with different JavaScript frameworks in projects across many industries.

10 Best JavaScript Frameworks for 2020

Take advantage over your competitors with cloud

Being a co-founder of Solidstudio, Paweł has got to see all the development phases. He’s a skilled professional with years of experience, both in the software and in the eMobility worlds.

Paweł Głogowski

At first glance, you may think that the e-commerce market has reached its maximum limit and there is no way to grow. However, by using new technologies companies can still increase their revenue - for example, by providing better recommendations or creating more attractive and user-friendly websites.

In this article, I will focus on describing new trends and technologies that help to improve e-commerce businesses. I won’t focus on Big Data technologies that are vital for e-commerce, but instead turn to the cloud technologies, Java, and Node.js.

There are always new trends emerging in online shopping on the e-commerce scene. First is using technologies that offer a literally one-click purchasing method that is quick but also safe. E-commerce ventures are also very interested in artificial intelligence (AI) - it includes chatbots or automatic customer service processes. AI is becoming more and more popular since it can easily interact with customers and facilitate the buying process. The last huge trend in online marketing is Machine Learning that helps profile the user experience for each individual buyer. However, it seems that e-commerce business won’t be able to achieve any of above if they don’t migrate their solution to the cloud.

One of the main problems in e-commerce business is its seasonality. There are some times during the year where the demand for online shopping rises - like Christmas or Black Friday. Companies used to lose billions of dollars because they couldn’t handle the increased volume of transactions. On the other hand, investing in architecture that will be used only for a couple of days during whole year isn’t very efficient. So is there a way to handle that situation? Yes - and the answer is the Cloud!

On AWS, it is possible to improve your architecture based on the current demand and then reduce it when it’s no longer required. This process is completely automated and adjusted to demand. It's very convenient and can help companies to save a tons of money. You can compare it to paying for electricity - you just pay for how much you consumed. You do not need to maintain and pay for servers on the virtual machine when you actually don’t need them.

Moving an e-commerce solution to cloud is also beneficial for other reasons. If your e-commerce solution is hosted on-premise, you need to deal with lot of additional problems like storing, maintaining and securing physical machines. Additionally, you should update software on a regular basis. Experience shows that it usually does not happen and sooner or later you end up with outdated software and less-than-expected availability. Also, you need more resources to maintain all servers. The cloud, on the other hand, is free from these issues. You need to set up your architecture once and then focus on developing software to meet the changing requirements. Your team won’t have to implement solutions like autoscaling or security backups since they are already provided by AWS.

At Solidstudio Software House, we have a lot of experience in moving monolith applications into the cloud, and maintaining and managing them accordingly. We are familiar with AWS solutions that can help your business grow.

Why Java is a great option for ecommerce?

Each branch of e-commerce is different and needs to face different problems. In e-commerce, there are many problems to solve. You will have problems with performance if you plan to sell a lot of cheap products relying on the scale of your project. However, if you plan to sell few but very expensive and luxury products then you need to rely on marketing and relations with customers. Each of these approaches requires different tools.

Java supports a lot of different frameworks which solve these problems. If you are an omnichannel company that needs complex tools for marketing or a CRM solution with customers, you may pick Hybris. If your company is smaller and you just need some basic support for orders or payments, you can choose one of the dozens available e-commerce solutions.

Java as a language that can also bring a lot of benefit for your company. It offers a lot of well-established tools, there are already many engineers who know how to use Java, the language itself is developed and updated accordingly to worldwide trends. That popularity makes it really easy to integrate Java tools with various solutions. The only drawback I can see from using Java as an e-commerce business is that for a very small scale it can be a little overkill. If you need to set up a small online shop, then using Java along with frameworks can end up becoming too costly. Consider using other languages to avoid following some Java conventions that are not feasible to all solutions.

Java is our main expertise at Solidstudio Software House and we already integrate our clients’ applications with dozens of third-party solutions, not only from the e-commerce field. We can help you choose the best option for your needs and integrate it with selected solutions seamlessly.

Node.js as a great tool for smaller scale.

If you do not need a complex CRM tool or support for online marketing and your business is rather small, you can start with some basic solutions based on Node.js. It uses Javascript for both the server and client side which can be beneficial since you need only experts with one programming language skills. It also offers great performance, so the costs of Node.js solutions are rather low. The existing Node.js frameworks like vue.js or koa.js can be really helpful for solving e-commerce problems. Node.js is a great tool to implement an MVP solution, however once your scale grows and you will need more complex tools and frameworks, we recommend switching to Java and one of its frameworks.

E-commerce has still a huge potential for growth and there is a lot of challenges that e-commerce ventures will have to face in the future. Technology can be a great support in achieving more, so keep a close eye on the cloud revolution. If you waste your time on outdated solutions, you will surely lose with your competitors. Start to move into cloud and use available tools wisely to be two steps ahead!

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AWS and Java - a good duo for your ecommerce environment

Improve your e-commerce application with AWS, Java and Node.js.

Serveless testing - tools and techniques.

Serverless architecture was one of the hottest topics in 2018. Just take a look at Medium articles and the number of threads and discussions on Reddit, Twitter, and other social media. It’s becoming more and more popular - and some well-known companies have started to use serverless architecture in their projects (Netflix or Coca-Cola, for example). However, popularity also serves to reveal some drawbacks and challenges of introducing serverless architecture. One of the biggest challenges is testing which is much different than in “traditional” applications. In this article, I would like to share some hints and tips about testing a 

The obvious difference between a traditional and serverless application is that it requires a lot of collaboration with external services - in the AWS world, it can be API Gateway, Dynamodb or S3, for instance. It’s often hard or even impossible to integrate with real services. Fortunately, there are some useful tools that can help with emulating some external services to help with writing tests. Let’s talk a little about possible tests that we can perform in the serverless world.

Firstly, to speed up every local development developers should be able to invoke code locally. At Solidstudio Software House we choose NodeJS to write our lambda functions because it’s lightweight and it’s easy to execute your code locally. We also find the serverless framework very handy as it that allows us to execute NodeJS code with some input parameters that can be really helpful.

Let’s imagine that our lambda subscribes to AWS S3 event for further processing. It thus has to consume the S3 event. It could be very helpful if we could use that event and invoke lambda as if it was consuming a real S3 event. We can easily capture the real AWS event and save it in a local JSON file. We can later use it for input of our lambda without actually using our infrastructure.

Of course, invoking lambda locally for several scenarios every time we want to change a single line of code isn’t very efficient. That’s why we need to write some automated tests. The most basic and easiest type of tests is, of course, unit testing. It's a must-have in all kinds of projects and the serverless environment is no different. The good thing is that serverless functions are "well-modularize” and so can be unit tested easily.

Like in any other system, we need to have decent code coverage in unit testing. We need to simply mock every interaction with external services. If we want to simulate some AWS events, we can use the captured AWS events discussed earlier. Every modern programming language has a framework to write and mock unit tests with. For NodeJS, we can use Mocha or Jasmine which offers a very easy way to simulate external events. Building and running tests must be a part of building a deployable package.

Once you have your code well-tested locally and are confident that the code is working correctly, you should deploy it to the development environment. This process need to be automated to avoid the potential risk of manual deployment. In serverless development, it’s crucial to test your function on the real environment because of some configurations like IAM permissions or AWS lambda limitations that don’t occur in the local environment like memory, disk space, timeout, payload size. Sometimes we forget about these limitations and something that works well on our local machine may fail in the real AWS world.

When our code has successfully reached the dev environment, you can check its behaviour by emitting event that particular functions are subscribed to. You can, for instance, upload a file to the target bucket and check if particular lambda behaves as we expect. Obviously, it's just a technique to debug and improve the development process - and testing cannot rely on it. We need some automated tests to make sure that all our functions work well after every change. We should run the entire test suite after applying changes to a single function.

Integration testing in serverless application

In a serverless project, we also need to have a decent integration of the test suite to make sure our application works as expected. Each lambda usually handles one event and most of the time we need several lambdas to cover our business story. Creating a user by the REST API can trigger events that will be consumed by several lambdas that will handle adding a user to DynamoDB, uploading photos to S3, or sending greeting emails. So, one integration test must make sure that all these three lambdas are invoked and done their job properly.

With a serverless framework along with Event Gateway, we can very simple hook up our functions to particular events and trigger our functions. Then we need to have code that will verify whether the lambdas have done their job well. It's good to write tests in one language rather than mix several techniques. The programming language should work well with AWS and update their SDK quite often so it works with the newest version of services.

Each test suite has to start with an emitting event and wait till lambdas react on it. That could be challenging as there’s no easy way to indicate whether a lambda is complete. One approach could be invoking some lambda and waiting for some fixed calculated time before testing - for instance, we could take lambda timeout as our wait time. However, it's not a good idea since delays may happen or some lambdas will finish before that time - its either risky or inefficient.

The best approach is checking periodically if some condition is fulfilled - if we expect an object to appear on S3 then we can check whether it’s there, as well as check for data in our storage (DynamoDB, RDS etc). We can then finish the test as soon as the lambda has finished its job, or fail if the outcome is not what we expected or the lambda hasn’t finished its work in a reasonable amount of time.

At Solidstudio Software House, we’ve started our latest project in a fully serverless architecture. We noticed that it requires a significant mindset change, but developers who have in microservice architecture should be able to move to serverless quite smoothly. As serverless architecture becomes more and more popular, they can take advantage of reliable and easy-to-use tools. We find serverless framework and event gateway as the best technology choice.

Read this article to get familiar with serverless testing.

What is Kotlin used for

12 NOVEMBER 2020 • 5 MIN READ