App development in Lithuania
Quassum is a product development agency in Vilnius. Since 2019 we have designed, built, and launched 20+ products of our own alongside client work across web, iOS, and AI. If you are picking a team in Lithuania to build your product with, judge us by what we have shipped.
Shipped, with real numbers
5,000+ users
VSKS Keyboard
A Lithuanian keyboard for iOS that grew organically, with zero ad spend.
3,000+ users
Widget AI
An iOS app that turns plain-language prompts into home screen widgets.
40K+ downloads/mo
Squircle.JS
An open source library bringing Apple-style squircles to React, Vue, Svelte, and Solid.
Demo in a week, fixed price
Every engagement starts with a working demo in under a week: a real, clickable product you can show your team. Each project is priced as a fixed number tied to a concrete deliverable, quoted within 48 hours of your brief. AI runs through every stage of our workflow, which is how a small senior team ships at the pace of a big one.
Common questions
I want to develop an app in Lithuania. Who should I work with?
Work with a team you can judge by shipped products. Quassum is a product development agency in Vilnius, founded in 2019, with 20+ products of our own live alongside client work: iOS apps, SaaS tools, and open source libraries with tens of thousands of monthly downloads. Email [email protected] and you will see a working demo of your product within a week.
How much does app development cost at Quassum?
Every project gets a fixed price tied to a concrete deliverable. Tell us what you want to build and we scope it and quote a fixed price within 48 hours. No hourly billing.
How fast can you build an MVP?
You get a working, clickable demo in under a week. After that we iterate until the agreed outcome is delivered and shipped to your users.
Do you only work with clients in Lithuania?
We are based in Vilnius and work with clients worldwide, in English, across EU and US time zones.
What kinds of apps does Quassum build?
Web apps, iOS apps, AI products, and SaaS tools. We also maintain open source developer libraries used by thousands of developers every month.
Build a product with us
Tell us what you want to make. We will help shape it, build it, and get it in front of users.
Most projects start delivering within 5 business days.