Key Engineer (Staff/Principal Level) – Backend, Infrastructure & IoT

Heidi Systems is building the data infrastructure layer for buildings and energy, transforming Europe's largest and most outdated industries through digitization. The company is a fast-growing, venture-backed startup with real customers and ambitious scaling plans. They are seeking an exceptional Key Engineer to become one of the technical pillars of the organization and take ownership of critical parts of their technology and infrastructure.

In this role, you will work directly with the founding team to design and evolve scalable, reliable backend and infrastructure architectures. You will own system architecture, backend engineering using Go and TypeScript, data infrastructure for meter and building data processing, production DevOps, PostgreSQL database engineering, and IoT connectivity challenges involving MQTT and wireless gateways. This is not a traditional execution role—you will have autonomy to make important technical decisions, challenge existing approaches, and define the engineering foundation of the company.