About the Job
We're a highly specialized tech startup in the heart of Berlin — working on one of the most relevant challenges of our time: bringing AI where it has the greatest impact — into the German public sector. What we build isn't theory. It's live, in production, used by over 1,300,000 people across 8 federal states every day — and growing fast. As one of Germany's fastest-growing GovTech startups (50% MoM growth over several months, currently at ~375k € ARR), something genuinely new happens here every single day. Hours fly by, weeks feel like months. No politics, no theatre — just 100% customer focus. In short: maximum impact, minimum friction.
Your Role
As Founding Fullstack Engineer, you own the technical vision, architecture and engineering culture behind Charly — the AI phone and chat assistant for German public administrations that serves both citizens and the public-sector employees. We're scaling fast, and we need senior technical leadership to grow the team and harden the platform for the next growth phase. This is a founding-team role: we're looking for a late cofounder who takes real ownership, not an employee — with equity to match.
Your first mission: scalability. Our biggest opportunity right now is making the platform scale cleanly to the next growth phase. You'll evolve the architecture from a fast-moving startup stack into a system that horizontally scales for citizen-facing telephony — the foundation everything else builds on.
Concretely, that means:
- Own the technical vision and architecture across the full platform — from the real-time voice pipeline to the multi-tenant chat products
- Drive our applied AI roadmap: LLM agents (pydantic-ai), RAG over pgvector, agentic crawling and evaluation systems for LLM accuracy
- Solve real scaling and reliability challenges for citizen-facing telephony: real-time processing, latency, uptime and horizontal scaling
- Own multi-tenant data isolation, security and DSGVO/GDPR compliance on a Postgres foundation (RLS, zero-trust access, migration discipline)
- Partner with the founders on product strategy, technical trade-offs and the long-term architecture of the company
- Lead, grow and mentor a small, senior engineering team across multiple services in Python and TypeScript, and set the hiring bar as we scale
What You Bring
This role is for you if you lead from the front — a proven engineering leader who never stopped building. You've grown and mentored teams, and you still have a strong hands-on mentality. Corporate mindsets won't thrive here.
- Proven experience leading and growing engineering teams, with a strong hands-on technical foundation you haven't left behind
- Deep experience building and operating production systems in Python and/or modern TypeScript/React
- Applied AI experience: LLM agents, RAG, and evaluation — you've shipped these to real users, not just prototyped them
- Strong instincts for multi-tenant data isolation, security and EU data protection (DSGVO/GDPR)
- A reliability engineering mindset for real-time, latency-sensitive, citizen-facing services
- The judgment to balance speed and substance — you ship fast prototypes, then harden them into robust, well-architected systems
- Nice-to-have: experience in regulated, security-critical, or public-sector environments
- Nice-to-have: German language proficiency
Benefits
- Competitive salary with significant equity — this is a founding-team role, weighted toward ownership
- A defining leadership role at one of Germany's fastest-growing GovTech startups
- Direct influence on technical vision, architecture and company growth
- A beautiful and central office right at Rosenthaler Platz
- 28 days of vacation per year
Application Process
- Informal application with CV to info@zaitgeist.com
- First interview with the founders
- Technical deep-dive & architecture discussion
- Culture & team fit
Rolling Deadline: We review applications on a rolling basis.
More information: hallocharly.de
