Interim Tech Lead & CTO · LLM systems

I build LLM products and agent systems that make it to production.

Startups and SMEs bring me in as interim technical lead when AI has to become a working product. I design the agent architecture, build the retrieval and evaluation around it, and leave behind a team that can run it.

Start a conversationGitHubLinkedIn
Experience
10+ years
Independent since
2017
Clients served
60+
Companies founded
3

A system I built, up close

What it does for the people using it, how it works, and the decisions behind it.

Fullstack developer · Aury · AI counselling

Voice check-ins for support between sessions

What a check-in is

Aury is a stress-management course developed with psychologists and therapists in Germany. Between course sessions, people sometimes need help right away. A check-in lets them open the app and talk through what is on their mind with an AI counsellor, out loud, and get a spoken reply. It is confidential and anonymous.

What made it hard

Someone who is stressed won't press a button, wait, and talk in turns. The conversation has to flow like a phone call. So audio streams in both directions, and turn detection works out when the person has actually finished speaking before the AI answers. And because people bring real problems, every response has to be safe, which is why the testing gets as much attention as the pipeline.

  1. Person checking in

    Talks freely, can pause

  2. LiveKit

    Streams audio, detects when they've finished

  3. Speech to text

    Streams as the person talks

  4. Counsellor agent

    LangChain, models on Vertex AI

  5. Text to speech

    Streams the reply back

Testing & tracingAutonomous QA agents hold real conversations with the system end to end. Langfuse traces every production run.
LangfuseQA agentsSimulated partners
  • Agents test agents. QA agents run whole conversations, instead of checking fixed inputs against fixed outputs.
  • Partners simulated. Mocked integrations, conversations and recommendations, so the platform could be validated without the partner's live systems.
  • LLM-assisted data work. An auto-tagging script labels large datasets, which feeds recommendation algorithms tested against cases taken from user stories.

More AI work

Interim CTO · DealSpecActive

AI toolsuite for M&A advisory

Designed the architecture, agent orchestration and data pipelines for a platform that handles deal management, documents and analytics for M&A advisors and investment bankers. Model calls are routed to EU deployments across several providers, with finance-specific embeddings for search.

Agent orchestrationHonopgvectorVertex AILangSmith
CRM & AI assistant · Greenline YachtsActive

Sales assistant inside a yacht dealer CRM

Built the CRM for Greenline's dealer network, then an agent inside it. Salespeople ask about their leads in plain language: it reads their email threads, finds who needs a follow-up, scores leads with web research and drafts replies for them to send. The models run on Amazon Bedrock in the EU.

Amazon BedrockTool callingRuby on RailsGmail API
Tech lead · Hirespace

RAG and AI workflows for recruiting

Led a five-person team. Built RAG and document ingestion pipelines, AI automation workflows, and streaming chat with LangChain and the Vercel AI SDK, on Express microservices with Inngest for background jobs.

RAGLangChainVercel AI SDKInngest
Agentic scheduling · HospitalityActive

AI Shift & Reservation Management

Agents plan shifts, resolve conflicts and coordinate reservations for hospitality venues, working against real-time availability.

Agent orchestrationReal-timeHonoNext.js

Before AI10+ years of web and cloud work

TypeScriptNode.jsReact / Next.jsRuby on RailsPHPVue / NuxtPostgreSQLRedisAWSAzureHerokuCI/CD

Background

I started with a master's in business & economics, taught myself to program, and ended up as CTO. That mix is why I'm good at translating between what a business needs and what the engineering has to look like.

I was co-founder and CTO of Shopboostr, an award-winning e-commerce ML startup funded through the EXIST programme. I was CEO and founder of Karyan Daze, a tech agency I grew to 15 engineers.

  • 2017 – nowIndependent practice · 60+ clients in DACH and France
  • BerlinKaryan Daze · CEO & founder, tech agency
  • BerlinShopboostr · co-founder & CTO, ML startup
  • AmsterdamFreelance · full-stack projects
  • UtrechtDeveloper · first role, part-time

How I work

Quality over shortcuts

Solutions built to last, not only for this quarter's demands.

Thrives in chaos

The messier the problem, the more energised I get.

3x founder

Team lead, developer and entrepreneur across several companies.

Leaves teams independent

Difficult concepts made transferable, so work continues after I leave.

Loyalty first

Partnerships built to last, reinvented along the way.

Brainstorm addict

The best ideas come from where disciplines meet.

What clients say

Hendrik worked as Head of Engineering at my startup, Hirespace.io. He was on track to become CTO. Hendrik was my trusted partner in building the company. He contributed not only on the technology side, but also to product, design, and hiring, which was critical. He helped shape the company’s culture — you are who you hire. His entrepreneurial mindset helped him deliver in a 0-to-1 environment where chaos and ambiguity are high. I could not have hoped for a better technology leader. I am grateful I had the opportunity to work with him, and I would love to work with him again. He’s a real A player. A rare talent.

Elad Leschem

5x Founder · CEO, Hirespace.io · Client

Hendrik combines strong technical expertise with a clear strategic mindset. He breaks down complex problems into actionable steps and consistently delivers high-quality results. What really stands out is his ownership — he doesn’t just execute tasks, he takes responsibility for outcomes. He communicates clearly, supports others, and brings a calm, solution-oriented approach even in challenging situations.

Ali Kilicaslan

Marketing & Growth · Managed Hendrik directly

He built our website and CRM and did an amazing job with both. He is super responsive and always quick to jump in when something comes up. No challenge ever felt too big for him — he just finds a way to make things work. Reliable, easy to work with, and someone you can count on throughout the whole process.

Janja Cerar Gazvoda

Marketing Manager, SVP Yachts · Client

I’m very satisfied with our collaboration. He is highly professional and brings advanced expertise in the IT field. This know-how was instrumental in helping us solve our challenges efficiently and continue to grow. Clear recommendation.

Aaron Tobias

Zumera GmbH & Agency · Client