AI Engineer (m/w/d)

Our client, based in Cologne, has its roots in web and app development, with a particular focus on building apps and platforms. More recently, the company has shifted its focus towards the integration of AI applications within the enterprise environment. With a clear focus on AI integration, consulting, and conceptualization, the company aims to be at the forefront of the technological revolution.

Remote 100%

Deutschland

IT & Services

Freelance

Your profile

  • Professional experience with at least one LLM-based system in production use, including responsibility for its operation and incident handling
  • TypeScript and Node.js at an advanced level: strict typing of non-deterministic model output, async and concurrency patterns, streaming responses, structured error handling
  • Next.js in production: App Router, route handlers, server actions, streaming to the client
  • Demonstrably taken over and improved existing codebases under 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 part of your everyday work: JSON Schema, Zod or comparable runtime validation, function calling, handling of malformed or partial output, context window management
  • Designed and run LLM evaluations
  • Experience with LLM tracing and evaluation tooling in a TypeScript codebase (e.g. Braintrust, Langfuse, Promptfoo, OpenTelemetry/Arize Phoenix)
  • Familiar with Postgres including vector search (pgvector or a comparable vector store), Docker, Git, CI/CD, and one major cloud platform
  • Working experience with the Anthropic and/or OpenAI TypeScript SDKs
  • Confident communication in English; German mind. B2

Nice to have

  • Durable workflow execution for long-running, unattended processes (Temporal, Inngest, Trigger.dev or comparable)
  • Agent orchestration in production: tool calling, recovery, multi-step workflows (Vercel AI SDK, LangGraph, Mastra, Claude Agent SDK, MCP TypeScript SDK)
  • Integration experience with enterprise systems such as ERP or CRM platforms like SAP
  • Security and data protection in LLM systems: prompt injection and data exfiltration defences, PII handling, GDPR-compliant design, EU-hosted or self-hosted inference
  • Structured or graph-based retrieval for entity-heavy data
  • Experience migrating live pipelines to a new model, embedding model or index without quality regression
  • Azure DevOps: Pipelines, Repos and Boards

Your mission

  • Take over and maintain existing LLM pipelines: assess the current architecture, identify failure modes, prioritise fixes, and refactor and extend the systems without disrupting production
  • Own our RAG systems end to end: document ingestion and parsing, chunking, indexing, hybrid retrieval (BM25 and vector), query rewriting, reranking, and grounded generation with citations
  • Implement and maintain chunk-level access control, index freshness and tenant isolation across retrieval systems
  • Develop content generation pipelines that deliver consistent quality at volume, including human review steps
  • Build and operate automated workflows against internal and third-party business systems (ERP, CRM, email, internal APIs), with durable and idempotent execution, retry and dead-letter handling, and approval steps for irreversible actions
  • Establish an evaluation framework for systems currently running without one: golden datasets derived from observed production failures, retrieval metrics, and more
  • Implement observability across the full request path
  • Optimise cost and latency through prompt caching, batching, model routing and use of smaller models where appropriate
  • Assess where deterministic logic is the better solution and implement it accordingly
  • Work directly with non-technical colleagues to specify and validate automated processes

Job Features

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