We craft
digital products
that matter.
Finnish software consultancy specializing in mobile development, web applications, and immersive 3D experiences. From startups to enterprises.
Full-stack expertise
for digital products
From concept to deployment, we handle every aspect of your digital product with precision and care.
Mobile Development
Native-quality mobile apps built with React Native. Cross-platform expertise for iOS and Android with seamless user experiences.
Web Applications
High-performance web applications using modern frameworks. From complex dashboards to elegant marketing sites.
3D & Interactive
Immersive 3D experiences and interactive visualizations. WebGL, Three.js, and React Three Fiber for engaging digital products.
Product Strategy
End-to-end product development from ideation to launch. UX design, technical architecture, and growth strategy.
Our tech stack
We use modern, battle-tested technologies to build fast, scalable, and maintainable products.
Frontend
Mobile
3D & Graphics
Backend
Companies we've worked with
From Finnish enterprises to global brands, we've helped build digital products used by millions.
Projects that made
an impact
A selection of projects from the past years. Each one unique, each one solving real problems for real users.
Posti Design System
Led the development of a comprehensive design system for Finland's national postal service. Built accessible, reusable components used across multiple teams.
Halton.com
Rebuilt the global website for Halton, a leading indoor air solutions company. Features immersive 3D product visualizations using React Three Fiber.
Noice Mobile
Developed the mobile application for Noice, a live streaming platform. Built real-time features with WebRTC and complex state management.
Adidas Finders
Built interactive product finder experiences for Adidas Running, Outdoor, and Bra categories. Helped millions of customers find their perfect fit.
Veri Health
Developed iOS and Android apps for metabolic health tracking. Complex data visualization and real-time sync with wearable devices.
Yle.fi Mobile
Contributed to Finland's national broadcaster mobile application, serving millions of daily users with news and media content.
Sharing knowledge at
global conferences
As a speaker at major React and React Native conferences, I share insights on cutting-edge topics including 3D graphics, cross-platform development, and mobile monetization strategies.
Chain React
Portland, USA
App.js Conf
Krakow, Poland
React Native London
London, UK
React Advanced
London, UK
React Day Berlin
Berlin, Germany
Built by an engineer
who ships
Fenrir Digital is the consultancy of Perttu Lähteenlahti, a senior software engineer with over a decade of experience building digital products.
With dual Master's degrees in Computer Science and Cognitive Science from the University of Helsinki, I bring both technical depth and human-centered thinking to every project.
I've worked with companies ranging from Finnish startups to global enterprises like Nokia, Adidas, and Posti. My expertise spans mobile development, web applications, and increasingly — immersive 3D experiences.
As a conference speaker at events like Chain React, App.js Conf, and React Advanced, I share knowledge about cutting-edge development techniques, particularly around 3D graphics in React Native.
Core Skills
Perttu Lähteenlahti
Founder & Lead Developer
Conference Talks
3D Experiences in React Native
Cross-platform 3D with Expo-GL
How to Make Money with React Native
Building Cross-Platform Libraries
Education
M.A. Computer Science
University of Helsinki · Minor in Economics
M.A. Cognitive Science
University of Helsinki · Minor in Usability Studies
Have a project
in mind?
Whether you need a mobile app, web application, or immersive 3D experience, I'd love to hear about your project.