AI & Backend Developer (m/w/d)

With Tess (gotess.de) we are building the first AI-agent for SMB-accounting on top of DATEV (Germany's most widely used legacy accounting software). Leveraging LLMs and AI-powered automation, Tess empowers accounting firms to close financials in record speed, thereby helping accounting firms tackle an industry-wide shortage of skilled talent.

We are growing extremely fast: We already serve >120 accounting firms , >500 bookkeepers and process >10,000 invoices per day .

As Backend Engineer , you’ll partner directly with Lukas, our Founder & CTO , and play a pivotal role in building the backbone of our AI-driven accounting engine. You’ll be close to the core logic, the data, the integrations — and the accounting magic. You will:

• Architect and expand the backend services that power document processing, reconciliation, and workflow automation
• Build reliable, high-throughput pipelines that ingest, normalize, and enrich accounting data
• Integrate deeply with DATEV and third-party financial systems
• Work closely with frontend and AI teams to deliver features end-to-end
• Own systems across their lifecycle — from design to deployment to continuous iteration
• Ensure our platform is fast, secure, resilient, and ready to scale with 10x more volume

What You Bring

• Solid backend engineering track record building and scaling data-heavy, business-critical applications
• Strong experience with modern backend stacks
• Familiarity with databases, event-driven architectures, APIs, and distributed systems
• Ideally hands-on experiences working with Large Language Models (LLMs) on business cirtical tasks
• A strong ownership mindset — you ship, you iterate, you raise the bar
• Excellent English communication (German not required)

What We Offer

• Real product ownership: Come in early and shape core platform architecture
• Senior-level mentorship: Work closely with seasoned founders and engineers
• Category-defining potential: Build infrastructure that could power tens of thousands of SMBs