Mobile development in the financial sector is not just about code—it’s the infrastructure relied upon by thousands of businesses. In this environment of extraordinary demands and rapid technological change, Vitalii Sosin is one of the few who not only follows trends but shapes them. As a Senior iOS Software Engineer at Raiffeisen Bank, he has become a key figure in building the next generation of mobile products. Thanks to his deep expertise, technical leadership, and successful personal projects, he confidently stands among the top specialists reshaping the face of digital banking in Russia.
We spoke with Vitalii about his journey in the industry, the challenges he’s faced, his own apps, the role of AI in development, and the future of the profession.
Vitalii, how did your journey in IT begin, and why iOS? What inspired you to make that choice?
— My journey in IT started with a childhood fascination for technology and a desire to create something that brings real value to people. When I discovered the Apple ecosystem, I was struck by its coherence and attention to detail. iOS is a platform where quality, performance, and UX are top priorities. That became the decisive factor: I wanted to influence the user experience and solve engineering challenges on the cutting edge of technological development.
Today you work at Raiffeisen Bank on a business-oriented app. What is your main role there?
— I am responsible for the development of the “Raiffeisen Business” mobile application, aimed at legal entities. My responsibilities cover the entire cycle—from designing the architecture of new services to releasing updates on the App Store. I lead key features, conduct code reviews, participate in interviews, and implement technological solutions that allow the bank to stay ahead of the competition.
Which of the projects you’ve implemented do you consider the most significant in terms of complexity, business impact, and personal challenges?
— Probably, it’s the launch of the regular (automatic) payments feature. This was one of the most important projects for the bank, and I essentially led its technical implementation. The architecture, business logic, integration with the backend — all of it was my responsibility. As a result, clients were able to automate routine operations, reduce costs, and the bank strengthened its position in the corporate segment. The feedback was exclusively positive.
You mentioned a deep architectural overhaul of the application. Tell us why this became a turning point.
— Initially, we had a monolithic structure that slowed down development. I initiated and implemented the transition to a micromodular architecture, introduced the Tuist and Swift Package Manager tools. This solution sped up builds many times over, improved stability, and allowed teams to work in parallel and independently. For the business, this meant: launching features faster and reacting to the market faster.
How tangible was the effect of your work in numbers?
— Here are a few telling cases. The admin panel I developed reduced the time to bring new features to market by five business days, allowing us to bypass App Store moderation. Switching to GraphQL doubled the loading speed of the main screens, significantly boosting performance. And the launch of key services — auto payments, the fast payment system, and QR payments — directly affected the growth of the client base, ensuring an increase in the bank’s share in the corporate banking segment.
You mentioned projects outside Raiffeisen Bank. Tell us about your own applications.
— I have six applications in the App Store, and each of them is a field for experiments.
For example:
– Random Pro — a randomness generator with AI elements, over 400,000 downloads, about 1 million views;
– EncryptoIt — a utility for quick and deep encryption of photos and videos;
– Pixel Mask — an application with steganography: it hides data inside images;
– CurrencyFy — a convenient currency converter;
– O-Chat — a super-private messenger without servers;
– A game in the style of “Crocodile” (charades), where one player draws and others guess, with its own backend.
Personal projects make it possible to try out new architectures and test approaches without fear for production.
Which of these projects were the most technologically challenging?
— Pixel Mask, in terms of concept and implementation, is probably one of the most unconventional projects. There are many subtle points there with colors, bytes, and security. Also, a challenging case was the integration of the C++ Smart Engine library for QR code recognition into the banking application. I had to write a wrapper for Swift to give the entire team access to the library’s functionality.
You not only code but also develop the team. What role do you play here?
— I am actively involved in building engineering culture. I conduct interviews, evaluations, technical assessments, and act as a mentor. My task is not just to assess technical level, but to help grow within the team, share approaches, and establish standards. A product is created by a team, and everything depends on its maturity.
What do you think about the role of artificial intelligence in development? Is it an assistant or a competitor?
— AI is a powerful tool, but only in the hands of a specialist. In my Random Pro app, AI generates greetings, and there it’s clear how important configuration is: the level of “imagination,” variability, structure. Beginner developers often rely on AI as magic, without delving into the fundamentals. That’s a mistake. AI should empower an expert, not replace them.
How do you develop as a specialist?
— Three sources: conferences and meetups — in our bank this is encouraged and paid for; internal community — we have our own knowledge base we share with each other; personal projects — the most lively and flexible way to learn in practice.
Technology is changing rapidly now. What would you advise young specialists?
— The main thing is to love your work. It’s a cliché, but it works. Without love for the product, for technology, for the result, it’s impossible to truly grow. And of course, fundamental knowledge, such as architecture, algorithms, systems. AI, frameworks, trends — these are tools, and without a foundation they are worth nothing.
Finally, what helps you recharge outside of work?
— I love active recreation, for example cycling or tennis. This gives an opportunity to step back, clear my head, and… often the best technical solution comes to mind. Rest is also part of productivity.
