By Ronny Shani
In recent years, Berlin’s startup scene has seen quite a few unicorns roaming around its alleys. One of the latest joiners to this prestigious category is Trade Republic, whose goal is to democratize access to capital markets.
Launched in January 2019 in Berlin, the company is active in 17 European countries: Austria, Belgium, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Lithuania, Luxembourg, the Netherlands, Portugal, Slovakia, Slovenia, and Spain. With a valuation of over $5B, Trade Republic is amongst the highest-valued private FinTech companies in Europe (and a Certified Unicorn: A privately owned startup with a valuation of at least $1B) serving over 1 million customers.
Project A has been investing in Trade Republic since its series A round — both financially and as an operational partner. Our Tech team spent two years (April 2020-March 2022) supporting the company in delivering a web app and several backend services that have helped Trade Republic evolve from a startup into a major European player.
Michael Lande — Head of Frontend Engineering, and Marco Gregorini — Senior Backend Engineer, who led these large-scale projects, share their takeaways and tell us how it feels to build the backbone of an app that millions of people trust their money with.
Frontend: Taking over the browser
Led by Michael, Project A’s frontend team was tasked with building Trade Republic’s web platform and laying the foundation for feature-parity with its mobile apps to enable users to track stocks, trade, and manage their trading portfolio via a browser.
As Trade Republic’s web presence was minimal, our experts had dual responsibilities:
- Work together with the internal team to define, develop, and launch the trading web app, and
- Build and grow the web team while establishing engineering culture and best practices in collaboration with Trade Republic.
Michael: When we joined in the summer of 2020, Trade Republic’s core business was mobile, and the web team was in its infancy. Headed by the very talented Lead Web Engineer Mohit Tilwani, the 2–3 people on the team worked on internal apps, and we helped establish an engineering culture that would allow them to deliver a best-in-class web app.
Our job was to support existing web assets (the internal back-office app, a small onboarding app, and the marketing website) while developing the public-facing trading app and the team that would eventually take over. We got to build everything from the ground up: Doing discovery and initial work on the app while developing methodologies and onboarding new hires.
Many questions arise at this point, both technical and organizational: How do we develop, what technology would work best, and what tooling do we use? How do we work as a team? How do we pair? How do we onboard newcomers?
We were at least half of the team for a long time, bringing our methodologies, experience, and expertise. This collaborative effort between our people and the Trade Republican people resulted in one of the best teams I’ve worked with. I left when there were around ten engineers in the web team — all committed to top quality and standards.
It was a great opportunity to be a part of establishing something like this. You can see that it had an actual effect on the product: We had a successful launch and continued to release many new features with a zero-bugs policy in place.
Backend: An API to remember
Marco spent 23 months supporting Trade Republic. He and his teammates developed several services as part of the Core Banking and Payment team, including APIs for internal and external communication with partners (banks and data providers) and apps.
Trade Republic was working with one bank (Solarisbank) when it launched. As the company prepared to expand into new markets and experienced hyper-growth, it needed to develop an infrastructure that would support the seamless integration of new banks, shifting away from having a single bank holding its entire user base’s liquidity.
What started as an item on the roadmap quickly became a priority. To continue onboarding new customers in Germany and other European countries, we had to complete the integration with other banks (Citibank and Deutsche Bank) as fast as possible — without compromising Trade Republic’s zero-bugs policy and high standards.
If you had to choose, what would you say was a highlight of your work?
Marco: Trade Republic is a bank that people trust with their money. When you provide a financial service, you must be a hundred percent reliable, and we took measures to ensure that the code and processes are resilient and scalable. The code we wrote guarantees that if something goes wrong, you’ll understand what happened and when, so you can swiftly resolve any issue without affecting end users.
Writing stuff from scratch is different from maintaining it. You have a chance to apply the good practices you’ve learned so far and avoid the bad practices, and this was very interesting in this context:
- What steps do you need to take when building an app that must be bulletproof?
- How do you track and record transactions?
- How to deal with high traffic and transaction volume?
Michael: Trade Republic’s app requires constant live updates. You connect to many data sources that keep pushing changes that need to be reflected in the UI. The most obvious example is stock price tickers. This functionality can affect performance, and we invested time in analyzing, mapping, and improving the app’s behavior to proactively mitigate its effects on the user experience. A fundamental technique was an in-memory cache layer that ensures the user sees the latest non-stale value and only then opens the rest of the connections and updates the UI. This increases the perceived performance when users navigate across pages, giving them the feeling of an immediate transition and ensuring they get the latest information.
Another way was to reshape how we consume and render the data efficiently. For example, specific data points — like a stock’s name — rarely change, so we can close this connection (or skip it altogether) and allocate more bandwidth to other parts.
Focusing on optimizing the UX for performance in this highly dynamic app at such scale and depth was very cool.
Stoked on stocks: Building products and teams
Trade Republic became a 5x unicorn a year after our people stepped in (May 2021) and helped launch a brand new web app, design and implement an API that moves loads of money, and build essential services from scratch. The company has recently raised another €250M Series C extension, bringing its total funding to $1.2B.
Anything you’d like to tell our future Tech Team?
Working with startups, we enter a lot of eclectic environments, but it’s important to recognize patterns that work and refine them. One such practice that’s worth preserving is a regular roundtable meeting — where engineers can exchange ideas beyond everyday product development — that gives the team space to form its culture together.
Want to turn your startup into a unicorn?
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