Custom AI software
Custom AI software development — at a fixed price
Off-the-shelf AI tools automate someone else's process. We build AI software around yours — and you know the full price before the project starts.
Who builds it: Onterion is a founder-led studio in Essen, Germany — more on how we work and who is accountable on the about page. Where fixed-price AI projects pay off first is summarised under industries.
Why custom AI software — and why fixed price
Most small and mid-sized businesses don't fail at AI because the technology isn't ready. They fail because generic tools don't fit the way their operation actually runs. A subscription chatbot doesn't know your approval chain. An off-the-shelf extraction tool doesn't know which fields your ERP needs, or what should happen when a supplier sends a malformed invoice at 4 pm on a Friday.
Custom AI software development closes that gap: we design the system around your workflows, your data and the systems you already use. The result is not another tool your team has to adapt to — it is software that quietly removes work from their day.
The second reason projects stall is commercial, not technical. Open-ended day rates put all the risk on your side: scope drifts, budgets balloon, and nobody can say what the finished system will cost. That is why every Onterion project is delivered at a binding fixed price, agreed before the build begins. Scope, timeline and price are written down. If we misjudge the effort, that is our risk — not yours.
What we build
Our focus is operational AI — systems that carry real workloads in daily business rather than demos that impress in a meeting and die in a drawer. Typical projects include:
- Document AI: invoices, delivery notes, contracts and inbound mail are read, validated and posted to your systems automatically — with a human review step wherever confidence is low.
- Process automation: recurring workflows such as email triage, quote preparation, order handling and reporting run end-to-end without manual copying between systems.
- AI assistants for your team: internal copilots that answer questions from your own documentation, prepare drafts and look up cases — grounded in your data, not the open internet.
- Workforce scheduling: shift planning that knows your qualification rules, working-time limits and fairness constraints, and re-plans automatically when someone calls in sick.
- Operational web applications: the surrounding software — dashboards, planning boards, portals — that puts AI output where your team can act on it.
Every system ships with the unglamorous parts that make AI dependable in production: validation rules, exception handling, audit logs and monitoring.
How the fixed-price process works
1. Discovery
We start with a structured look at your operation: which workflows consume the most time, what data exists, which systems are involved. This is a short, focused phase — typically a handful of conversations and a review of sample data, not a months-long audit. The outcome is a clear picture of the use case with the greatest leverage and a realistic assessment of what AI can and cannot do for it. If we conclude that a project isn't worth your money, we say so.
2. Fixed-price proposal
You receive a written proposal that defines the scope in plain language: what the system does, which systems it connects to, what "done" means, and when it will be delivered — with one binding price. You can compare it, question it and plan your budget around it. There are no hidden day rates and no "estimate subject to change".
3. Build
We develop in short iterations, and every iteration ends with working software you can click through. You see real progress within weeks, correct course early and never wait for a big-bang reveal at the end. Requirements that emerge during the build are handled transparently: small adjustments are absorbed, genuine scope changes get their own mini-proposal — again at a fixed price.
4. Operate
Go-live is not the end of the project. We train your team, monitor the system in production and stay responsible for it running reliably. As your operation grows, the system grows with it — with the same fixed-price logic for every extension.
What's included in every project
- A binding fixed price, timeline and written scope before kickoff
- Integration with your existing systems (ERP, time tracking, email, industry software)
- GDPR-compliant architecture: data processing agreement, data minimisation, auditable processing
- EU data residency on request — your data stays on German or EU infrastructure
- Human-in-the-loop review steps wherever automated decisions need oversight
- Documentation, team training and a defined support arrangement after go-live
What drives the price
Every proposal is individual, but the cost drivers are consistent and we are transparent about them:
| Factor | What it means in practice |
|---|---|
| Process complexity | How many steps, decisions and exceptions the workflow contains |
| Integrations | Number and quality of systems to connect (modern API vs. legacy export) |
| Data situation | Whether usable data exists, and how much cleanup it needs |
| Review requirements | How much human oversight regulated or high-stakes steps require |
| Operating model | Cloud, EU-hosted or fully on your own infrastructure |
A focused first project — one workflow, one or two integrations — is deliberately scoped so that a first production version is live within weeks, proves its value and builds the foundation to extend from. Starting small is not a limitation; it is how sustainable automation programmes begin.
You own the result
A fixed price would mean little if the system tied you to us forever. It doesn't. Every project is built on proven, maintainable technology and handed over with documentation, source code and a clean deployment setup. You own the software outright — including the right to run it, change it and have anyone you choose maintain it. Most clients stay with us for operations and extensions because it's convenient, not because they're locked in. That distinction matters more than any feature list.
The same thinking applies to AI components: where a commercial model is the right tool we use one, where an open model on your own infrastructure serves you better we use that — and the proposal states which, and why. Model choices are documented and replaceable, so your system doesn't inherit a dependency on any single AI vendor's pricing or policy changes.
GDPR and the EU AI Act, from day one
Because we are a German studio, European regulation is not an add-on for us — it is the default. Systems are designed for data minimisation, processing is logged and auditable, and model choices take into account where your data is allowed to travel. Where the EU AI Act imposes obligations — transparency, human oversight, documentation — we build them into the architecture rather than bolting them on before an audit.
Who this is for
Our clients are typically owner-led or operations-heavy businesses with 20 to 250 people: property managers, logistics operators, hospitality groups, healthcare providers, professional services. What they share is not an industry — it is a situation: recurring work that eats skilled people's time, knowledge trapped in inboxes and spreadsheets, and software that almost fits but never quite does.
If that sounds familiar, the first step is a free, concrete conversation about your process. You'll leave it with a clear idea of what's feasible, what it would roughly take — and whether we're the right partner for it.
Frequently asked questions
How can a fixed price be possible for custom AI software?
The discovery phase exists precisely to make it possible. Before any quote, we map the workflow, the data and the integrations in enough detail to scope the work honestly. You then receive a binding fixed price for that defined scope. Small adjustments during the build are absorbed; a genuine change of scope gets its own small fixed-price proposal, so you are never surprised by an open-ended invoice.
How quickly will we see working software?
Within weeks, not quarters. We build in short iterations, and every iteration ends with software you can click through on your own cases. A first production version of a focused project is typically live within a few weeks, so you correct course early instead of waiting for a big reveal at the end.
Do we own the software and the source code?
Yes, outright. Every project is handed over with source code, documentation and a clean deployment setup, and you have the right to run, change or have anyone maintain it. Where we use AI models, the choice is documented and replaceable, so you never inherit a lock-in to a single vendor's pricing or policy.
Is our data handled in line with GDPR and the EU AI Act?
Yes. As a German studio we treat European regulation as the default: data minimisation by design, EU data residency or your own servers on request, a data processing agreement as standard and auditable processing logs. Where the EU AI Act requires transparency, human oversight or documentation, we build those into the architecture rather than bolting them on later.
What if we are not sure AI is worth it for our business?
Then the discovery conversation is the right place to find out. If we conclude a project will not pay for itself, we tell you plainly instead of selling it anyway. The initial consultation is free and leaves you with a clear view of what is feasible and roughly what it would take.