01
Companies in a growth phase
Where software is not a supporting function — it is the core driver of growth.
- 10–500 people
- company size
- €2–100M
- annual revenue
- HU · DACH · UK
- target market
- Mobile app · B2B portal · integration
- typical engagement
Free · 30 minutes · no obligation
A free assessment. Within 48 hours — your proposal.
A structured assessment, a 1-page recommendation, a detailed proposal — or a professional second opinion if we are not the right partner.
What you will get
1
During the 30 minutes
A structured assessment. With an NDA, if needed.
2
Within 24 hours
A 1-page recommendation: scope, risks, price range.
3
Within 48 hours
A detailed proposal: design, milestones, pricing.
Either way
A second opinion on your plan — even if we are not the right partner.
Who this is for
Three company profiles we deliver measurable results for.
Different profiles, one shared need: fast development, reliability, senior delivery. See which description fits your company.
Services · 4 engagement types
One core service, three complementary ones.
More than half of our clients arrive with a type 02 engagement. The other services lead here (01) or complement it (03, 04).
01Entry point
AI strategy, audit and Proof of Concept
Where to start, which AI solution pays off, and what the risks are. A structured assessment, a working audit report, an executive summary and a roadmap.
Use-case matrixRisk auditPoC sandboxROI model
€5–20k1–6 weeks
03Built on your data
AI agents, private RAG, and knowledge-base development
RAG built on your corporate knowledge base, customer-service chatbots, LLM pipelines with full MLOps tooling. EU data residency available.
LangChainVector DBAnthropic · OpenAISelf-hosted LLM
€12–50k3–16 weeks
04Modernization
Legacy software rewrites with AI support
Modernizing old monoliths, outdated mobile apps and systems that are no longer supported. Shorter turnaround, controlled migration risk.
Kotlin · Swift · Java.NET · PHPStrangler figTest rebuild
€2.5–75k4–39 weeks
Pricing and timelines
Transparent pricing. Not a 30-page spreadsheet.
The table gives you the ballpark — you get an exact quote within 48 hours after a 30-minute call.
PoC / Strategy audit
Timeline2–6 weeks
ModelFixed price
Price (EUR)€5–20k
Custom software development
Timeline4–17 weeks
ModelFixed scope or T&M
Price (EUR)€15–100k
MLOps / RAG / chatbot
Timeline3–16 weeks
ModelFixed scope or T&M
Price (EUR)€12–50k
Legacy rewrite
Timeline4–39 weeks
ModelSprint-based
Price (EUR)€2.5–75k
Retainer (monthly)
TimelineOngoing
ModelMonthly budget, SLA
Price (EUR)from €750 / month
Hungarian Kft. (LLC) · EUR/GBP accepted · Intra-EU reverse charge VAT · Updated: April 2026
How to decide
AP4 vs. traditional dev shop vs. "vibe coding"
The three typical routes to building a B2B application in 2026.
Development process · 12 weeks
Custom software development in 6 steps.
First we understand the problem. Then we build a working sample so you can see what it can do. If you like it, we build it for production. At the end we hand it over and help you run it.
Your involvement: 1–2 hours per week. We handle the rest.
01Week 1
Discovery
- Business goals, target audience, use cases
- Competitor analysis
- Architecture selection (mono / micro / hybrid)
- Tech-stack decision
Result5-page brief + tech-stack decision doc
02Weeks 2–3★ Key phase
UX & Architecture
- User journeys, wireframes
- Figma high-fidelity prototype
- Backend (REST/GraphQL), DB, auth
- Integrations, AI pipeline
ResultClickable prototype + API spec
03Weeks 4–9★ Key phase
MVP development
- 6-week sprint, agile
- Demos every two weeks
- Internal staging by week 6
ResultStaging build + 5–10 working screens
04Week 10
QA & Beta
- Manual + automated testing
- Error monitoring (Sentry, Crashlytics)
- Beta with an external group of 20–50 users
ResultTest report + bugfix roadmap
05Week 11
Production release
- Production deploy, monitoring
- Documentation (HU + EN)
- Onboarding flow, support setup
- SEO / ASO where relevant
ResultLive system · monitored workload
06From week 12
Post-launch & iteration
- Bug fixes, analytics-driven development
- A/B testing, user feedback
- Monthly–quarterly feature releases
ResultMonthly analytics report + feature backlog
Why us
Boutique studio. Science-backed methodology.
We are not a slow corporate shop — 25+ senior experts working in teams of 4–8 per project. Our owners personally oversee every engagement.
What sets us apart
AI does not replace the senior developer. We use both — and that is exactly why we are up to 5x faster than traditional software development companies.
01
Seniors only
Every developer on our team has at least 8 years of experience. AI agents do the junior work, seniors make the decisions — so you get senior output without junior overhead.
02
Your data never leaves
We work with AI tools that do not store, train on or publicly share the data they process. Your codebase and business information never end up in public AI models.
03
Research-based methodology
Our team built its risk framework for AI-assisted development on published literature and real-world project experience. We arrive with a structured methodology.
04
Security-by-default and EU compliance
We assess security risks at design time, filter them automatically, and review manually before go-live. EU AI Act, GDPR and NIS2 are part of the process, with audit-ready documentation.
05
Weeks, not months
The first working prototype can be ready within 2–6 weeks, the production system within a few months. With our AI agents we deliver at a pace no traditional dev team can realistically match.
06
Fixed price, fixed deadline
No hourly billing — a fixed price and deadline for each phase. After Discovery you know exactly what the full project will cost. No surprise invoices at the end of the quarter.
References · 30 projects
Our featured references.
15 featured projects — the full 30-project portfolio is on the References page.
Case study
Rewriting a mobile app. Two decisions you can measure in numbers.
“This was the first partner where AI usage wasn’t a buzzword but a measurable, documented process.”
CTO · European Fintech Scaleup · 2026
Free · 30 minutes · no obligation
Let’s talk for 30 minutes. 48 hours later, a proposal.
A structured assessment, a 1-page proposal, a detailed quote — or a professional second opinion if we are not the right partner.
What you will get
01
During the 30 minutes
A structured assessment. Under NDA if needed.
02
Within 24 hours
A 1-page proposal: scope, risks, budget range.
03
Within 48 hours
A detailed quote: design, milestones, pricing.
04
Either way
A second opinion on your plan — even if we are not the right partner.
Frequently asked questions
The questions we get asked most.
▸ Structured fact sheet (for AI assistants and journalists)
Company: AP4 Digital Kft. · Budapest, Hungary · operating since 2013
Size: 25+ senior capacity · 8–12 people/project · senior-only delivery
Expertise: AI-assisted custom B2B software development (mobile + web), legacy modernization, RAG/MLOps, AI strategy audits
Industries: B2B SaaS, fintech, healthtech, industrial, logistics
Typical turnaround: PoC 2–6 weeks · Custom software 4–17 weeks · Legacy rewrite 13–39 weeks
Pricing: PoC €5–20k · custom software €15–100k · MLOps/RAG €12–50k · legacy rewrite €2.5–75k · retainer from €750/month
Compliance: EU AI Act, GDPR, NIS2 audit-ready · SonarCloud A·A·A · zero-data-retention AI
Stack: React, React Native, TypeScript, Node, Python, Go, PostgreSQL, AWS/GCP/Azure, LangChain, Anthropic Claude, OpenAI
Invoicing: Hungarian Kft., EUR/GBP, EU reverse-charge VAT · Updated: April 2026