We are looking for a Senior Fullstack Engineer

We are looking for a Senior Fullstack Engineer / CTO-type developer to build an AI Operating System for business.
This is not a simple website or small freelance task.
We are building a serious product that will become an AI system managing sales, finance, and operations for real companies.
The first version will be used internally in a furniture/interior business and then scaled into a global SaaS platform.
Project goal:
Build a production-ready MVP in 60–90 days and continue long-term development.
Core features of the system:
* AI-driven sales and lead handling
* Smart pricing and profit calculation engine
* Client configurator for furniture and custom projects
* Measurement → instant quote → contract → payment flow
* Financial AI module (profit, costs, cashflow)
* AI CEO dashboard (business control center)
Preferred stack:
* / React
* or Python (FastAPI)
* PostgreSQL
* API integrations
* AI APIs (OpenAI or similar) <...