Crypto Index a crypto portfolio app
A mobile app for tracking crypto portfolios: it shows the whole portfolio in one place and works out the buys and sells needed to rebalance it.
Fintech and payments
Payment systems, banking apps
A fault in a payment system can cause direct financial and business harm. That is why we base the build on years of banking systems experience, thorough testing and verifiable behaviour.
For fintechs, payment service providers, merchant systems and e-commerce platforms.
Related work
Anonymised case (NDA)
Instant payments by QR code
QR-code instant payments to the national standard: customer app, merchant console and settlement on a single platform.
Other work
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horgaszjegy.hu — a national fishing licence system
The Hungarian National Angling Association's licence system, used by many points of sale. We developed the framework its web interface is built on.
-
onlinePénztárca — a shared discount network for online shops
A shared discount balance that grows from purchases made at partner stores and can be used when shopping online.
Years of banking systems work
Our experience with banking systems helps us plan from the start for the requirements banks commonly place on integrations, checks and approvals.
- Technical design of a retail banking frontend.
- Architecture of an international online banking platform.
- Connecting that platform to the bank's back-end systems, leading a development team of more than 10.
- Later, we also took part in building a complete instant payment platform, from the customer app to settlement.
What does it cost?
We use the same pricing bands for three project sizes across every service area:
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MVP or pilot
HUF 3–8M
Typically 4–12 weeks
-
Production system
HUF 8–20M
Typically 3–6 months
-
Platform
from HUF 20M
From 6 months, quoted individually
Before every project: Review and technical plan — HUF 0.9–1.5M, 2–3 weeks.
What each range includes, and what drives the price
Prices are net of VAT and indicative. The final price is set after the review.
Already have a plan or a prototype?
If you have already worked out your idea with ChatGPT, Claude or another AI tool, we don't need to start from scratch. We review the specification, the screen designs, the prototype or the source code, and tell you what can safely be built on. What works, we keep; what needs it, we fix or redesign.
When we are not the right choice
- If an off-the-shelf payment provider module solves your problem, use it instead of calling us.
- If you need advice on financial licensing or legal compliance, that calls for a lawyer and a specialist, not a developer.
- If your total project budget is under HUF 3M, a smaller off-the-shelf option will serve you better.
Frequently asked questions
Have you worked on a live payment system?
Yes. Our most recent work is an instant payment platform we can only describe without names because of a confidentiality agreement. We also have years of banking systems experience.
Why can't I see the client's name?
Because we are under an NDA. In a conversation we can show more.
How long does a project take?
The review takes 2–3 weeks and ends with an itemised quote. Adding a payment feature typically takes 2–4 months, depending on the standard it has to meet and the deadlines the bank sets.
Who owns the source code?
You do. We put it in the contract, and the review materials stay with you even if you continue with someone else.
Andor Kerti
Founder, agentic software engineering
At Appific, we have used an AI-agent-based development system since 2024: the agents work within strict technical rules, while a specialist decides on the system's structure and accepts the result. I have more than twenty years of experience as a software developer and architect; I previously worked on fintech systems. I now put that experience to use designing systems, reviewing them and managing their technical risks.
LinkedIn (opens in a new tab)Tell us what you are working on, and we will show you how we would start.