Founding Engineer - Backend & Platform

A seed-stage B2B SaaS startup in the German tax advisory technology space is looking for a Founding Engineer - Backend & Platform to join their small, fast-moving team in Berlin. The company is building an AI-powered operating platform that unifies legacy accounting systems across tax advisory firms - automating workflows, enabling data flows, and powering safe AI applications at scale.

As a founding engineer, you will design and operate the core backend that powers this platform. Your work will define how data moves, how work gets done, and how the system scales across dozens of firms. This is a true greenfield environment: your architectural decisions matter from day one, and your code runs in real production environments immediately.

You will work directly with the CTO on system design and core technical decisions. Visa sponsorship is available for this role., * Design, implement, and operate core backend services spanning accounting, payroll, reporting, and compliance domains.

• Build robust data pipelines to ingest, normalize, and reconcile data from accounting software (DATEV), banks, and document sources.
• Design and operate workflow orchestration systems for long-running, stateful, failure-prone processes.
• Own correctness, observability, and performance of the systems you build - end to end.
• Make pragmatic architectural decisions in a greenfield codebase with real production stakes.
• Ship to production frequently; your code runs inside live tax advisory firms from the start.
• Collaborate directly with the CTO on system design and foundational technical choices.

Must-haves (dealbreakers):

• Proven track record of building and operating production backend systems (language-agnostic background welcome; stack is TypeScript-heavy today).
• 3+ years of experience building backend systems., * Strong TypeScript skills.
• Experience designing systems with a focus on data integrity, workflows, and reliability.
• Strong observability, monitoring, and performance optimization skills for production systems (metrics, tracing, logging).
• Experience integrating DATEV and/or other accounting software into a production platform.

Nice to have:

• Hands-on experience building data pipelines to ingest, normalize, and reconcile data from DATEV, banking, and document sources.
• Experience designing and operating workflow orchestration for long-running, stateful, and failure-prone processes.

Who thrives here: Engineers who take full operational ownership, prefer robust systems over theoretical elegance, and are energized by messy, real-world infrastructure problems at an early-stage company.