Forward Deployed Engineer, Frankfurt am Main

About Donnerstag.ai

We are building the autonomous reconciliation layer for the CFO stack. Our platform automates financial reconciliation at the position level: matching invoices, deductions, credit notes, payments, and delivery data across multiple data sources to detect discrepancies, prevent revenue leakage, and produce audit-ready traceability for finance teams.

Our customers are enterprise finance and operations teams across the EU, Türkiye, and the UAE in logistics, automotive supply chain, payments, and retail. We work with controllers, CFOs, and IT directors of large enterprises where data correctness and audit traceability are non-negotiable. We are backed by top European and US venture capital. Our engineering team is led by an experienced CTO with a deep AI background, working alongside engineers in Germany and Spain.

The Role

This is not a traditional product engineering position. You partner directly with enterprise customers to understand how their billing, settlement, and operational data actually flow, then build the reconciliation logic that runs against real data in production.

You sit at the seam between our platform and the customer's reality. Every engagement starts with a different ERP setup, a different chart of accounts, a different definition of done. You translate that into deterministic matching logic, ship it, and own the outcome.

You also represent Donnerstag.ai engineering in front of customer technical teams: walking ERP architects through integration design, explaining matching logic to controllers, and answering the hard security questions live in enterprise sales cycles. Every pattern you see flows back into the core product, the template library, and our delivery playbook.

This is a hands-on generalist role. No two engagements look the same. You move between extraction pipelines, reconciliation configuration, customer workshops, and production debugging in the same week.

Key Responsibilities

Own customer delivery

• Run Proof of Value engagements end to end, from kickoff to the first reconciled period
• Lead technical discovery sessions with customer finance, IT, and operations teams
• Translate open-ended business problems into deterministic, auditable matching logic on the Donnerstag platform
• Own the customer outcome: reliability, accuracy, and the trust of the finance team

Build the integrations

• Build and operate integrations with ERP systems (SAP, Oracle, Microsoft Dynamics, NetSuite), TMS, WMS, EDI feeds, bank statements, and PDF or email-based invoice flows
• Work with structured invoice standards (XRechnung, ZUGFeRD, Peppol, FatturaPA, Türkiye e-Fatura) and the unstructured documents that arrive next to them
• Write production-quality code (Python and TypeScript) for connectors, parsers, normalizers, and customer-specific reconciliation rules

Hold the line on what AI is for

• Configure and tune the LLM-powered ingestion path (OCR plus LLM extraction for PDFs, Excel, unstructured supplier documents) with explainability, data-quality flags, and exception handling
• Defend the architecture decision live in customer rooms: language models do extraction and assist configuration, the matching engine is deliberately deterministic
• Enforce data handling rules for every model call: PII exclusion at ingestion, EU residency, audit-grade logging of every prompt and response

Represent engineering in front of customers

• Run workshops with CFO offices, controllers, and finance operations teams
• Walk through findings and discrepancies with auditors and Big-Four advisors when the customer brings them in
• Handle the engineering side of security reviews, vendor due diligence, and DPAs

Required Qualifications

• Located in Frankfurt or willing to relocate. On-site presence in our office is the default, not the exception
• Several years of professional software engineering experience, with at least one end-to-end production system you owned from design to operations
• Hands-on experience integrating with enterprise systems (ERP, billing, ledger, TMS, or comparable). You know that the API spec and the actual data are rarely the same
• Strong written and spoken communication. You can sit with a controller, an ERP architect, and a CFO in the same week and earn trust in all three rooms
• Working proficiency in German (B2 or higher) and fluent English. You are comfortable running a customer meeting in German
• Comfort separating probabilistic from deterministic components in one system. You can explain to a procurement team and a Big-Four auditor why one part of the product uses LLMs and another part categorically does not
• Strong programming skills (Python and TypeScript preferred)
• Ownership mindset. You do not hand off problems
• Comfortable with regular travel to customer sites across the EU, Türkiye, and the UAE

Nice to Have

• Previous experience in forward deployed, solutions engineering, implementation engineering, or technical consulting roles
• Direct experience with reconciliation, accounting close processes, or AR/AP automation
• Background in fintech, accounting tech, ERP, logistics tech, or B2B finance automation
• Working knowledge of e-invoicing standards (XRechnung, ZUGFeRD, Peppol, FatturaPA, Türkiye e-Fatura)
• Production experience with LLM extraction pipelines, eval frameworks, or multi-provider routing
• Experience with PostgreSQL, Docker, and Google Cloud
• Turkish or French language skills
• You have been part of a fast-growing startup and enjoy the pace

Our Tech Stack

Cloud: Google Cloud Platform (Cloud Run, GCP services)

Database: PostgreSQL on Google Cloud

Backend: Python, containerised with Docker

AI / ML: Multi-provider LLM stack (OpenAI, Anthropic, others)

What We Offer

• Highly competitive compensation benchmarked against the senior engineering market
• Founding FDE scope. You define how delivery gets done at Donnerstag, working directly with the CPO and the Frankfurt team
• Real product surface area. You will work on a deterministic reconciliation engine processing real enterprise transaction volumes, not a demo, not a wrapper around an LLM
• Direct line to founders. You work alongside the CPO in Frankfurt
• Travel budget for customer sites across the EU, Türkiye, and the UAE, plus team offsites with the wider engineering team
• Modern tech stack and the freedom to choose the right tools for each engagement

What Makes You a Great Fit

You have shipped systems inside large, messy enterprise environments and you know that the work that matters happens after the contract is signed. You get energy from walking into a new customer landscape, mapping the data, and watching the first reconciliation run clean. You can hold your own in a room with a controller, an auditor and an ERP architect and you want to be the person who closes the gap between what the platform can do and what the customer actually needs. You want significant impact on both product and delivery, in a market and at a company where the next two years will define the trajectory.

Donnerstag.ai is an equal opportunity employer. We value diversity and are committed to creating an inclusive environment for all employees.