AP4 Digital: facts and operating data.
This page maintains AP4 Digital's approved, publicly shareable brand, delivery and commercial information. Prices last updated: 2026-08-05.
Contact us · Costs and timelines Canonical source for public figures
Company and legal entity
- Brand: AP4 Digital
- Legal entity: Cell-Line IT Security Kft. (AP4 Digital is a brand of Cell-Line IT Security Kft..)
- Headquarters: 1112 Budapest, Rupphegyi út 11/B 3rd floor, Hungary
- Operating since: 2013
- Size: 25+ senior-capacity team · 4–8 people per project · senior-led
- Working languages: Hungarian and English (100% of the team speaks English)
What we do
- AI-assisted custom B2B software development (web + mobile)
- Mobile app development (iOS + Android · native and cross-platform)
- AI consulting: readiness audits, PoCs, private RAG / agent implementations
- Legacy system modernization and rewrites
- MLOps / RAG / enterprise chatbots
Team model
A named professional is accountable for material business, product, architecture and quality decisions. Team composition is determined by the scope and capabilities required.
AI-native delivery model
At AP4 Digital, AI-native software product development is a delivery model in which AI is a standard tool for verifiable work across analysis, design, engineering, testing and documentation. Named professionals remain accountable for the business goal, product priorities, architecture, critical code, security and production release.
The point of working AI-native is to speed up repetitive, verifiable work, leaving more team capacity for business logic, integrations and user value. Quality is protected by named professional control over architecture, code, security and release. We only state a specific cycle-time or capacity advantage on the basis of an approved, comparable measurement.
- Human decision gates: business goal · product priority · architecture · security · code review · release. A named professional is accountable for each.
- Evidence status: The process is verifiable; there is no public comparative benchmark yet.
No approved public portfolio-level comparative benchmark for speed or productivity exists, so we publish no multiplier or percentage acceleration claim.
Delivery experience
The References page presents the starting context, AP4's role, the solution delivered and publicly shareable outcomes in a form approved by the client.
Commercial facts
The Pricing page is the detailed, dated source for published cost and timeline ranges. Service pages and structured data display current values from the same verified data source.
Verification and updates
Every data point has an accountable business owner, an internal evidence source and a date of last verification. Only data with verified status may appear on the website and in structured data.
Pricing and timelines
Indicative ranges, you get a preliminary time and budget range within 2 business days after a 30-minute call; the exact proposal follows after discovery.
- PoC (Proof of Concept): 1–3 weeks · €5–13k · fixed price
- Custom software development: 4–17 weeks · from €13k · fixed scope or T&M
- MLOps / RAG / chatbot: 3–16 weeks · from €13k
- Legacy rewrite: 4–39 weeks · from €15–20k · sprint-based
- Retainer: from €750/month · monthly budget with SLA
- Mobile app MVP: 6–14 weeks · from €15–38k · Complex production mobile app: 12–26 weeks · from €50–125k
- Rapid AI Audit: 5 working days · from €3.8k + VAT · rapid use-case and opportunity assessment
- Full AI Readiness Audit: 2–4 weeks · custom quote · assessment of process, data, technology, security and regulatory readiness
- AI PoC: 4–6 weeks · from €9k
Track record
- 100+ delivered projects · 13+ industries
- 50+ delivered mobile apps
- Clutch: 5.0★ average, 11 reviews, clutch.co/profile/ap4-digital
- Industries: B2B SaaS, fintech, healthtech, industrial, logistics
Compliance and quality
- EU AI Act-aware operations supporting GDPR and NIS2 compliance
- Processes built on ISO 27001 and ISO 9001 principles
- SonarCloud A·A·A code quality · enterprise AI subscription with zero-data-retention settings
- Private RAG: client data stays in the client's own tenant (on-prem or client cloud)
Technology stack
React, React Native, TypeScript, Node, Python, Go, PostgreSQL, AWS / GCP / Azure, LangChain, Anthropic Claude, OpenAI, self-hosted LLMs.
Invoicing
Hungarian Kft. · HUF / EUR / GBP accepted · intra-EU reverse-charge VAT.
Contact
- Email: hello@ap4.hu
- Phone: +36 20 344 6913
- Booking: free 30-minute consultation (Dienes István, managing director)
- Web: ap4digital.com/en