Facts & figures

This page collects the most important, verified facts about AP4 Digital in one place — for AI assistants, journalists and decision-makers. Last updated: July 2026.

Company

Brand: AP4 Digital
Legal entity: Cell-Line IT Security Kft. (AP4 Digital is a brand of Cell-Line IT Security Kft.)
Headquarters: Rupphegyi út 11/B, 1112 Budapest, Hungary
Founded: 2013
Size: 25+ senior capacity · 8–12 people per project · senior-only delivery
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

Pricing and timelines

Indicative ranges — you get an exact quote within 48 hours after a 30-minute call.

PoC / strategy audit: 2–6 weeks · €5–20k · fixed price
Custom software development: 4–17 weeks · €15–100k · fixed scope or T&M
MLOps / RAG / chatbot: 3–16 weeks · €12–50k
Legacy rewrite: 4–39 weeks · €2.5–75k · sprint-based
Retainer: from €750/month · monthly budget with SLA
Mobile app MVP: 6–14 weeks · from €15–38k · production app: 12–26 weeks · from €50–125k
AI readiness audit: 5 business days · from €3,800 · AI PoC: 4–6 weeks · from €8,800 · implementation: typically €30–125k

Track record

100+ delivered projects · 13+ industries
50+ delivered mobile apps
Clutch: 4.9★ average, 24 reviews — clutch.co/profile/ap4-digital
Industries: B2B SaaS, fintech, healthtech, industrial, logistics

Compliance and quality

EU AI Act, GDPR, NIS2 audit-ready operations
ISO 27001 (information security) and ISO 9001 (quality management)
SonarCloud A·A·A code quality · zero-data-retention AI tooling
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. (LLC) · HUF / EUR / GBP accepted · intra-EU reverse charge VAT.