Some finance teams never get past the first security question. Where do the invoices go when the model reads them? If the answer is a US cloud API, or a consumer file drive, the conversation is over. Defense suppliers, hospital groups, tax advisors, and law firms are not being difficult. Their auditor, their RFP, or their professional secrecy rules already decided.
High-security Cortena is the same bookkeeping product on a different deployment target. Application, AI inference, email, and reference data stay inside a German or customer-controlled perimeter. No Google. No OpenAI. No US cloud APIs for core processing. You still set the rules, and nothing posts without your approval.
Who this is for
This path is for buyers who cannot accept a consumer cloud for invoice and payment data. If a standard SaaS deployment already satisfies your security review, you do not need it.
- Defense and dual-use: supply-chain invoices, restricted vendors, and a preference for a hard boundary around processing.
- Medical and life sciences: hospital groups, labs, and commercial documents that must stay inside a controlled estate.
- Tax advisors and law firms: client confidentiality and professional secrecy, with German residency for AI and email.
- Any buyer whose RFP forbids third-party LLM APIs and consumer cloud file sync.
What local means
Local is not a sticker on the same stack. Sensitive invoice PDFs, bank data, and AI prompts stay inside the perimeter. That is the promise, and it has four parts.
- AI on your side of the wall. Open-weight models run on Hetzner or on customer GPU servers. Inference does not leave the environment.
- Email stays internal. Send and receive run inside the estate. A separated public ingress exists only where mail must enter.
- No consumer cloud files for core bookkeeping. Reference data and files sync inside the environment. No Google Drive or similar for that work.
- Agent orchestration and guardrails run inside the estate, not as a third-party SaaS bolted on the side.
Same Cortena product. Different deployment target. You set the rules. You approve.
Shared: a German high-security platform
Shared is Cortena on German servers. It is multi-tenant, on an isolated high-security stack. Storage and processing are air-gapped, with clearly defined ingress and egress where they are necessary: inbound email, outbound email for receivables, dunning, and reminders, and export to the accounting system you already use. Access is VPN only.
This is the fastest path to German residency and local AI. Cortena operates and patches the platform. You do not buy hardware or wait on a long server procurement. The product roadmap stays the same, with the high-security constraints baked in.
Dedicated: a single-tenant estate you control
Dedicated is Cortena for one customer only. It runs on your premises or on dedicated servers you own or control. Cortena operates it. You hold the legal control. Encryption at rest is on by default.
Only your data and processes sit on that stack. You control the network, the backups, and who can audit access. That is the stronger story when procurement language requires you to hold the keys, or when you cannot share infrastructure with any other customer.
How to choose
Both paths keep the same sovereignty baseline. The choice is how much isolation your auditor and your procurement team need.
- Data must stay in Germany. No US AI. No Google Drive. Shared high security.
- You cannot share infrastructure with any other customer. Dedicated.
- You need on-premises racks, or your contract must own the servers. Dedicated.
- You want sovereignty without running IT yourselves. Shared, or Dedicated on servers Cortena manages.
- Procurement requires a dedicated estate plus local AI and email. Dedicated.
If shared German high security already satisfies the auditor, dedicated is usually more isolation than you need.
Same product, different deployment
This is not a fork. Payables, receivables, approvals, and the booking-ready handoff to DATEV, Exact Online, or Twinfield stay on the product you already know. Accounting export targets remain the integrations you choose. Cortena's own processing stays local. The trail is GoBD-aligned: you see every step, and nothing posts until your team signs off.
Book a demo. Tell us what your auditor and procurement require. We map residency, isolation, and network with your IT and security team, then recommend Shared or Dedicated and a rollout that fits.