We build custom software, tailored to your business.
From websites to internal systems: we start by understanding how your business actually runs, then build the solution around it. A first working version can be ready in as little as 3 days — depending on how complex the job is and what capacity we have free.
Whatever your business actually needs
We don't sell off-the-shelf packages. You tell us where things get stuck, and we build the solution for it — a website, an internal system, or an app.
A website for your business
A site with a look of its own: who you are, what you offer, prices, gallery, booking — exactly as much content as you actually need.
- Custom design, not a template
- Works just as well on a phone as on a desktop
- Google Analytics: see how many people come, and from where
- Search optimization, so Google finds you too
Internal systems
When the business runs on notebooks and separate spreadsheets, it costs time and mistakes slip through. We build a system shaped around the way you actually work.
- Warehouse and inventory management
- Customer, order and appointment records
- Invoicing and reports in one place
- Permission levels: everyone sees only what concerns them
Mobile apps and integrations
An app for your customers or your team, or connecting the systems you already use so nobody has to enter the same data twice.
- iOS and Android apps
- Connecting booking, payment and invoicing systems
- Syncing data between your existing software
- Automating repetitive manual work
And we don't disappear afterwards.
Hosting, maintenance and support stay with us — free for 12 months after launch. If you need something that isn't on this list, just ask: so far there hasn't been a job we couldn't solve.
What we've built so far
An internal system for a healthcare provider and a mobile app — both in real, everyday use with real users. Alongside them, two demo sites we built for fictional businesses: they show how we work when it comes to websites.
Delelő & Éjfél
A demo website for a fictional Budapest bistro and bar: an opening-hours arc in the hero, a palette that follows the time of day, a menu and table booking.
Kontúr
A demo landing page for a fictional studio management product: an animated hero, an interactive capacity table, a phone view and pricing.
UltiPro mobile app
A React Native mobile app for Ulti score tracking and gameplay statistics, available on the App Store, with cloud sync, guest mode and a dedicated marketing website.
Medical software
An internal healthcare web application with role-based access, questionnaire workflows, medical software integration, and automated data ingestion from 5 medical devices.
Who we are
There are three of us, all software developers, with 4–5 years of professional experience each. We work on production systems at larger companies day in and day out — the kind where a mistake costs real money. We started Rosavallis so that this kind of work reaches businesses that never had access to it.
The three of us take every project from start to finish: no subcontractors, no junior the work gets handed down to. We price each job to what it involves, and we're working with launch pricing at the moment.
Why us?
- 4–5 years each, building production systems in daily use
- AI-assisted development: a first working version can be ready in as little as 3 days
- A fixed price you agree to up front, with no extras added later
- 12 months of free support, 3 months of free bug fixing
- Not a one-off cost: the solution keeps working for you
- You talk directly to the person building your system
How it works
Four steps, no complications. You'll always know where your project stands, and you can ask us anything — we reply within 48 hours on business days.
No salespeople, no agency.
You talk to the person building your system. No middlemen, no misunderstandings, no waiting weeks for an answer.
1. We talk
You tell us what you do and where things get stuck. Twenty minutes is enough, over the phone if you like — and it's free.
2. You get a fixed price
In writing: what we build, for how much, and by when. Nothing beyond that quote gets added to the bill later.
3. We build it, you try it
You try it live and tell us what to change. Within the agreed scope we keep adjusting until it's right.
4. It goes live, and we stay available
We launch it on your own domain. After launch we support it free for 12 months — including one small content change a month — and fix anything that went wrong on our side free for 3 months.
What most people ask
If your question isn't answered here, write or call — we get back to you within 48 hours on business days.
What does it cost?
We price every job to what it actually involves, so we always talk first — that consultation is free and commits you to nothing. After it you get a fixed price in writing, and nothing beyond that quote gets added later.
How long does it take?
A first working version can be ready in as little as 3 days, depending on how complex the job is and what capacity we have free. A larger internal system naturally takes longer, but the deadline is fixed when we agree on the work.
Why is it that fast?
Because we work with AI-assisted development: it takes most of the routine work off our hands, so our time goes into the thinking and the testing. The code still passes through us — three developers with production experience behind them.
What do you need from me?
Tell us what you do and send over whatever already exists: logo, texts, photos, prices. If those aren't ready, we help you put them together.
Who owns what you build?
You do. You're not renting it from us and it isn't locked to our platform: the site runs on your own domain, in your name, and you can take it with you at any time.
Is there a monthly fee?
Not from us. Hosting and the domain have a yearly cost, which we tell you up front. After launch we support the site free for 12 months, and that includes one small content change per month.
What if we find a bug after launch?
Anything that went wrong on our side we fix free for 3 months after handover. A new feature or a larger extension is a separate agreement — with a fixed price agreed up front, as always.
Do you only work in Budapest?
Budapest and the surrounding area is home, but we can work online from anywhere in the country. We reply within 48 hours on business days.
Let's work out what you need.
Write a few lines about what you do and what you had in mind. We always price to your actual requirements, so we talk it through first — that consultation is free and commits you to nothing.