Web apps
Fast, multilingual Next.js products with SEO that works: storefronts, dashboards, SaaS.
Software studio · Luxembourg
Four products built. Yours is next.
DevFIRE WEB designs, builds and runs its own apps for web and iPhone. We build for clients the same way: web apps, mobile apps and AI features, from the first sketch to launch day.
- 4own products
- 12+years building software
- 6languages, EN to LB
- EUhosting, GDPR by design
- Next.js
- Flutter
- TypeScript
- Supabase
- Google Gemini
- React Native
- Vercel
- Stripe
- Postgres
- Cloudflare
What we do
From idea to app store
Mobile apps
iPhone and Android from one Flutter codebase, offline-first where it counts, store-ready.
AI features
Vision, voice and generation with guardrails, run on the server in the EU, never on the phone.
Design systems + lead
Token-driven design systems and frontend architecture, or a hands-on lead for your team.
Our products
Built and run by us
Four products we design, build and operate end to end. The same team, process and stack you get as a client.
Web liveMobile coming soon
Portia
portia.ro · portia.luYour whole city, one app.
Order food, book a haircut, reserve a table or rent a car from the businesses around you. Each merchant gets its own storefront, couriers get their own app.
View Portia
Web liveiPhone in review
KachFit
kachfit.appPlan the week, shop once, cook what you have.
Meals planned around your goals, one merged shopping list for the shops you use, and AI that reads your fridge and receipts. In English, French, German and Luxembourgish.
View KachFit
Web liveiPhone in review
BeaconStep
beaconstep.appReal-world quests, verified by the phone.
AI drafts a city or campus quest in seconds; the app checks place, time and photo on the spot. For team days, school trips and family weekends.
View BeaconStep
Private betaiPhone coming soon
Nomentous
nomentous.appMake the no's the number.
An AI coach for the uncomfortable ask: a daily mission, a boost before you go, and a high-five for every no. 100 no's in 30 days, until asking feels easy.
View NomentousHow we work
You see it before we build it
Talk
One call about what you want to build, for whom, and what success looks like. You get a written scope and a fixed first phase.
Design first
Tokens, logo and clickable HTML mocks of every screen. You approve them before a line of product code is written.
Build in the open
Short cycles with a live preview link. You watch the real thing grow, not a status report.
Launch + run
Store listings, SEO, monitoring and EU hosting. We stay on after launch, the way we run our own products.
EU-only dataSupabase in Frankfurt, row-level security on every table.
AI on the serverModel keys never ship in the app. Users review before anything changes.
Multilingual day oneEN, FR, DE, LB, RO, HU: strings from one dictionary.
Accessible by defaultWCAG AA contrast checked automatically, in both themes.
Behind the studio
Otto Kartye
Started as a network admin in Satu Mare in 2004, moved to Luxembourg in 2013 and led frontend teams for fintech, telecom and SaaS platforms. Founded DevFIRE WEB to build products end to end: mobile, web, AI and the backend behind them.
12+years building software
15engineers in the largest team led
6languages spoken
Satu MareLuxembourgTeam leadArchitectDevFIRE WEB
Read Otto's storyStart a project
Got an idea? Let's build it.
Tell us what you want to make and who it is for. Otto reads every message personally.