AI Engineer – Typescript / LLMS systems

Darwin Recruitment; Köln; Hybrid; EUR 129.000 - 203.000; Vollzeit

Zusammenfassung

Darwin Recruitment invites a Senior AI Engineer to own and evolve live LLM systems using TypeScript and Next.js. You’ll manage content generation pipelines, RAG over internal documents, and workflows closely integrated with core business systems.

The role focuses on production-grade code, incident handling, and practical retrieval strategies. German language skills are a plus, with hybrid work in Cologne and remote collaboration available.

Qualifikationen

• Production experience owning at least one LLM-based system in production.
• Advanced TypeScript and Node.js with strict typing and streaming responses.
• Next.js in production: App Router, route handlers, server actions, streaming to client.
• Experience taking over and improving existing codebases under live production traffic.
• Practical retrieval expertise: hybrid search and embedding model selection.
• Experience processing real-world documents (PDFs, DOCX, HTML) including OCR.
• Structured outputs and tool calling with validation and error handling.
• Experience designing LLM evaluations and tracing/eval tooling in TS codebases.
• Familiarity with Postgres and vector search, Docker, Git, CI/CD, cloud.

Aufgaben

• Own live, production LLM systems and incident handling.
• Develop content generation pipelines and retrieval-augmented generation over internal docs.
• Integrate tightly with core business systems and existing production stack.
• Maintain robust JSON Schema, function calling, and error handling across services.

Kenntnisse

LLM systems ownership

Advanced TypeScript

Next.js in production

Production incident handling

Hybrid search / RAG

Document processing (OCR/PDF/HTML)

JSON Schema / validation

LLM evaluation tooling

Postgres / vector search

Docker / CI/CD / Git

OpenAI/Anthropic SDKs

Tools

Postgres

Vector search

Docker

Git

CI/CD

Cloud platform

Langfuse

Braintrust

Promptfoo

OpenTelemetry

Arize Phoenix

OpenAI SDK

Anthropic SDK

Jobbeschreibung

Senior AI Engineer – TypeScript / LLM Systems (DRWN)

Job title – Senior AI Engineer (TypeScript / LLM Systems)

Client Location – Cologne, Germany

Remote work offering – Hybrid, 2 office days per week

Client Industry – AI / Software Technology

Contract Length – Ongoing freelance engagement (length to be confirmed at interview)

Contract type – Freelance

Project focus

You’ll take ownership of live, production LLM systems: content generation pipelines, retrieval-augmented generation (RAG) over internal documents, and automated workflows tightly integrated with core business systems. The stack is TypeScript and Next.js end to end, and this is applied engineering on systems already in production, not model training or fine-tuning.

Key skills and Experience required

• Professional experience owning at least one LLM-based system in production, including incident handling
• Advanced TypeScript and Node.js: strict typing of non-deterministic model output, async/concurrency patterns, streaming responses, structured error handling
• Next.js in production: App Router, route handlers, server actions, streaming to the client
• Proven track record taking over and improving existing codebases under live production traffic
• Practical retrieval expertise: hybrid search, embedding model selection, cross-encoder reranking, metadata filtering, permission-aware retrieval, and structured diagnosis of poor retrieval quality
• Experience processing real-world documents (PDFs with tables, scanned material, DOCX, HTML), including layout-aware parsing, OCR, and evidence-based chunking
• Structured outputs and tool calling as everyday practice: JSON Schema, Zod or comparable runtime validation, function calling, handling malformed/partial output, context window management
• Experience designing and running LLM evaluations, plus tracing/eval tooling in a TypeScript codebase (e.g. Braintrust, Langfuse, Promptfoo, OpenTelemetry/Arize Phoenix)
• Familiarity with Postgres and vector search (pgvector or comparable), Docker, Git, CI/CD, and a major cloud platform
• Hands-on experience with the Anthropic and/or OpenAI TypeScript SDKs
• Confident English communication; German is a plus

Marvin Mills