The verdict in three sentences
Securing a business web app in Berlin starts with a security audit at 3,000-12,000 EUR, followed by hardening that represents 10 to 25% of the build budget. The non-negotiable fundamentals: encryption, role-based access control (RBAC), logging and penetration testing. A GDPR breach can cost up to 4% of global turnover or 20 million euros: security is not optional, it is insurance.
The cost of securing a business app
Security is priced in layers. Here are 2026 orders of magnitude for an app handling personal or sensitive data.
| Service | Content | Budget |
|---|---|---|
| Security audit | OWASP analysis, code review | 3,000-12,000 EUR |
| Penetration test (pentest) | Simulated attack, report | 4,000-10,000 EUR |
| Encryption and RBAC | Data at rest/in transit, roles | 8-12% of build |
| Logging and monitoring | Logs, alerts, traceability | 4-8% of build |
| Sovereign EU hosting | France/EU datacenter, backups | 300-1,200 EUR/month |
| GDPR compliance | Records, DPA, policy | 3,000-8,000 EUR |
On an 80,000 EUR build, full hardening thus represents 8,000 to 20,000 EUR — far less than a single data breach.
OWASP, GDPR and the cost of non-compliance
The OWASP Top 10 lists the most critical vulnerabilities. Addressing them at design time costs a fraction of an incident.
| Risk | Example | Measure | Cost of an incident |
|---|---|---|---|
| Injection | SQL, commands | Parameterised queries | Full data breach |
| Broken access control | Unauthorised access | Strict RBAC | Fine + loss of trust |
| Exposed data | No encryption | TLS + encryption at rest | Regulatory sanction |
| Misconfiguration | Open ports, defaults | Server hardening | Server compromise |
| No logging | No traceability | Logs + monitoring | Impossible to audit |
The data protection authority can impose a fine of up to 4% of global turnover or 20M EUR. In 2025-2026, enforcement intensified on apps handling HR, health and financial data.
Mini case study
Julien, IT director at a 90-person biotech SME in Berlin, deploys an internal app handling employee health data. A breach would expose the company to a fine and lost contracts. Kolonell runs a 7,500 EUR audit, fixes 4 critical vulnerabilities, implements encryption, RBAC and logging for 14,000 EUR, and sovereign hosting at 550 EUR/month. Total investment: 21,500 EUR in the first year. Compared with a potential fine of several hundred thousand euros and lost clients, the return on risk reduction is immediate.
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FAQ
Is a security audit really necessary?
Yes, as soon as the app handles personal or sensitive data. An audit at 3,000-12,000 EUR finds flaws before an attacker exploits them, for a fraction of an incident's cost.
Where should sensitive-data apps be hosted?
In a datacenter located in the European Union, ideally sovereign, with encrypted backups. Count 300 to 1,200 EUR/month depending on load and service level.
What is RBAC and why does it matter?
RBAC (role-based access control) ensures each user only accesses authorised data. It is the first defence against unauthorised access and a GDPR requirement.
How much does GDPR non-compliance cost?
Up to 4% of global turnover or 20 million euros, not counting reputational and customer loss. Compliance typically costs 3,000 to 8,000 EUR.
How often should we run a pentest?
At least once a year and after every major change to the app. A pentest costs 4,000 to 10,000 EUR and provides an actionable report.
Let's scope your project. Tell us the nature of the data processed, the size of your app and your deadline: we will cost the audit and hardening plan. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
