About the Role
Join a 15-person B2B construction technology startup as a Software Engineer – AI, owning end-to-end AI features that solve real problems for construction professionals. You'll sit within the Product & Engineering team, working across the full stack — from database schema and LLM optimization to UI — while building platform foundations that allow new use cases to ship in roughly a month.
What You'll Do
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Build and own end-to-end AI features from concept through production, including document versioning and agentic chat workflows.
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Design and implement features across the full development lifecycle: database schema, LLM tuning, evaluation, and UI.
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Manage evaluations, scoring, and error analysis on new and shipped AI features to ensure consistent quality.
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Contribute to the workflow harness, decision-trace standard, and evaluation tooling that accelerates shipping new use cases.
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Build reusable human review and approval surfaces that establish trust in AI output.
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Model and evolve a construction ontology and project graph, including entity resolution across documents such as bills of quantities, contracts, and drawings.
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Design features that link answers to evidence and make decisions auditable and traceable.
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Extend multi-modal ingestion of unstructured documents — PDFs, scans, drawings, and 3D models — at scale.
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Build read/write integrations with customer systems (document management, ERP) to complete workflows end-to-end.
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Contribute to scalable data pipelines and support native BIM/DWG file processing.
What We're Looking For
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3+ years of full-stack software engineering experience in fast-paced, B2B startup environments.
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Proven track record delivering production-grade applied AI features to customers.
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Proficiency in TypeScript, Python, and SQL for building full-stack applications.
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Experience building backend APIs and database schemas (e.g. Fastify, Prisma, or equivalent).
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Experience integrating and optimizing LLM APIs (e.g. OpenAI, Azure, Gemini, Cohere, or similar).
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Experience with cloud infrastructure such as AWS (RDS, S3, Elastic Beanstalk) or equivalent.
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Experience building data pipelines and ETL workflows for processing unstructured data at scale.
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Experience with vector databases and semantic search implementations.
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Experience designing and implementing evaluation frameworks and error analysis for AI systems.
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Experience building internal platform or developer-facing tooling that other engineers ship on top of.
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Startup exposure or early-stage founding experience; comfort with autonomy, ambiguity, and end-to-end ownership.
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Fluent spoken and written English; German is a genuine plus but not required.
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Familiarity with workflow orchestration tools (e.g. Prefect, Airflow), document processing/OCR, or observability tooling (e.g. Datadog, Langfuse) is a bonus.
Compensation & Benefits
Salary range: €80,000 – €120,000 per year. Visa sponsorship is not available for this role.
Location
On-site, five days per week in Berlin, Germany. Candidates must be based in Berlin or willing to relocate.