Levi9 hosted the ninth edition of our internal hackathon — Hack9, held simultaneously across all our Delivery Centres in the Netherlands, Romania, Serbia and Ukraine.
This was one of the largest Hack9 events so far, bringing together 132 participants in 29 teams, all working under the shared theme: “The Vibe Coding Rush.”
For the third year in a row, artificial intelligence took center stage at Hack9. Teams were challenged to build a web application that would transform internal Levi9 processes — from sick leave requests and business travel bookings to maintenance reports, education tracking, and asset reservations — using AI to optimize, automate, and enhance the experience.
Despite the complexity of the challenge, nearly 40% of the teams delivered a fully functional application within just eight hours — a task originally estimated to require two months of work. Impressively, these solutions reached around 70% production readiness, with most teams estimating that just two to three more weeks would be enough to make them fully deployable.
Here’s how the top three teams brought that challenge to life, combining technical expertise, teamwork, and a whole lot of vibes.
🥇 Pump.AI (Belgrade): When AI Becomes a Teammate
The winning team from Belgrade, Pump.AI, set out to reimagine one of Levi9’s core internal tools: OpenAir. Known for sometimes being unintuitive, based on levi niners’ experience, OpenAir offered the perfect challenge — and opportunity — for simplification and reinvention.
“OpenAir can be clunky. We wanted to strip away the noise and build something that’s actually pleasant to use,” said Nemanja Pavlović.
What distinguished Pump.AI was their deep integration of AI at every stage. They used ChatGPT Deepsearch for research, Replit for development, Cursor for documentation and test creation, and even relied on AI to help write Jira tickets and validate completed tasks.
“We didn’t just use AI, we embedded it into our workflow so deeply that it felt like a member of the team,” Nemanja explained.
The Pump.AI team from Belgrade consisted of Nikola Radosavljević, Kosta Aćimović, Sofija Despotović, Nemanja Pavlović, and Zoran Nikić. Roles were clearly split: Nikola led research and decision-making validation, Nemanja built the UI and frontend in Replit, Kosta handled test coverage and stability, and Zoran and Sofija covered QA and end-to-end testing. A failed experiment with an AI chatbot interface slowed them down — but they quickly shifted focus to features that delivered the most value.
“The biggest takeaway? A small, well-organized team with the right AI support can outperform a traditional team three or four times the size,” said Nemanja.
🥈 Rookies (Novi Sad): Turning Prompts into Gold
Second place went to Rookies from Novi Sad — a team that turned a crisis into a learning opportunity. From the start, they decided to let AI lead the way.
“We deliberately changed our mindset — less ‘thinking like devs,’ more ‘thinking like AI facilitators,’” said Darko Opalić, DevOps Engineer.
But just an hour into the hackathon, they accidentally lost what they described as their “best prompt ever” due to a temporary ChatGPT session. Without a saved copy and no undo option, they had to start from scratch.
“That mistake probably cost us first place — but it made us better. We recovered, rebuilt, and kept the vibe going,” said Darko.
The strength of the Rookies team from Novi Sad lay in its diversity. With Željko Miladinović and Nebojša Tamindžić as developers, Darko Opalić as the DevOps engineer and team lead, Đorđe Elez – finance manager, and Viktor Kovač, the Delivery Centre Director, the team brought a wide range of perspectives and skills to the table. Despite the rocky start, they functioned like clockwork, leaning into AI tools like ChatGPT, Replit, and Cursor to regain momentum.
“Hack9 2025 proved just how much AI can compress the idea-to-delivery timeline — if you know how to prompt it and when to pivot.”
And of course, plenty of coffee-fueled laughs helped ease the pressure: “Too much caffeine + adrenaline = some unforgettable moments. What happens at Hack9 stays at Hack9!”
🥉 AIgents of Change (Kyiv): Clean Design, Sharp Delivery, and a Secret Easter Egg
The third-place team, AIgents of Change from Kyiv, prioritized clarity and reliability over complexity. While many teams experimented with advanced AI assistants and voice interfaces, they opted for a clean, intuitive UI that enabled them to deliver core functionality quickly and effectively. The team — Ivan Nikolaievskyi, Igor Tananika, and Vladyslav Snitsar — focused on building a stable, user-friendly application that showcased thoughtful execution and smart use of AI.
“We didn’t invent a new use case — we focused on delivering the core functions in the cleanest way possible,” said Ivan Nikolaievskyi, a Software Engineer.
They used Replit to rapidly generate working application components and Cursor to support testing and refactoring. Their structured approach — including a shared GitHub repo and kanban-style project board — helped keep their three-person team aligned and effective.
“After a few prompt iterations, Replit started ‘getting’ us. The last three features came out nearly perfect — just from changing the feature name in the same prompt,” Ivan shared.
Despite a few setbacks — like Replit loops that broke their app and depleted credit budgets — the team’s long-standing work history made collaboration smooth. And yes, they left a little surprise behind:
“We added a cheeky easter egg — not John Doe, but someone movie fans might recognize. Just for fun.”
“This hackathon showed me how far AI tools have come. Used wisely, they can easily 10x your productivity — but they still need human judgment and control.”
The Scoring System: AI Meets Human Insight
Just like in 2024, Hack9 2025 combined AI-assisted scoring and human judging. While the AI system evaluated documentation quality, feature implementation, and
3 technical structure, human judges weighed in on UX, originality, presentation flow, and team collaboration.
“The top 10 teams were incredibly close. It came down to details — not just what you built, but how you told the story,” noted Ivan from AIgents of Change.
And the best team name award went to the Romanian team AI’m Possible, consisting of Silviu Petronel Rusu, Ciprian Lucian Voloc, and Iustinian Dominte – also rated by AI!
Reflections and Advice from Hack9 2025
Nemanja (Pump.AI): “Sign up. It’s fun, intense, and reveals what your team can really do.”
Darko (Rookies): “It’s a perfect blend of chaos, learning, and teamwork. And way too much coffee.”
Ivan (AIgents of Change): “Don’t wait to be ready. Prepare a little — then jump in and enjoy the ride.”
Viktor Kovač, our Delivery Center Director and one of this year’s participants among the winning teams, shared his reflections on Hack9 2025:
“It was incredible to see the energy, creativity, and spark in the eyes of every participant — all driven by the desire to make a real difference. Hack9 2025 proved that smart development isn’t just about speed; it’s about clarity, creativity, and purpose. By understanding customer needs, shifting our thinking, and using AI as a strategic partner, we unlock new ways to tackle complex problems and deliver more with less. This mindset doesn’t just help us build better products — it helps us win more work, innovate smarter, and stay ahead. The future is here, and we’re ready to shape it with bold ideas, sharp execution, and technology that works for people — the Levi9 way.”
This year’s Hack9 was all about trusting your team, guiding AI, and riding the rhythm of creative problem-solving. Our levi niners showed once again that technology works best when it works with people — not instead of them.
A huge thank-you goes to our incredible organizers — Novak Pantelić, Goran Militarov, Ihor Kozlov, Gabriela Hanganu and Andrija Šinković — for bringing Hack9 2025 to life with dedication, creativity, and flawless coordination.
See you in 2026. New tech, new challenge — same vibe.
In this article:
