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32-40 hours a weekAvailable immediately; start date by agreementEmployed or freelanceAmersfoort / hybrid

Senior Full-Stack AI Engineer

Build AI systems that don't just work on demo day, but keep working reliably for clients for years. Architecture, security, full-stack TypeScript, and the freedom to do it properly.

“We are explicitly looking for someone who complements our stack, not copies it. Deep expertise we lack in-house matters more to us than experience with precisely the same tools we use.”

Sjoerd Tiemensma, Senior AI Engineer

In short: TwoFeetUp increasingly delivers AI solutions that don't just work, but keep working reliably for clients for years. That calls for someone who looks beyond the first working version: architecture that scales, security that holds up, and code someone else can still maintain a year from now. You'll work closely with Sjoerd, challenging each other's technical thinking.

What will you do?

You join a small technical team with plenty of ownership, direct communication and clients who genuinely benefit from what you build. The journey from initial workflow analysis to production deployment often takes weeks, not months.

Building AI agents and multi-agent systemsEnd to end, from design to production. Agents that don't just work in the demo, but still run reliably for clients months later.
Making architecture choices that lastSetting up multi-tenant AI products securely. Designing for scalability, security, observability and maintainability. Not just "does it work now?" but "where will this be in a year?"
Shipping full-stack featuresA modern TypeScript stack: React/Next.js, Node. From frontend to API to deployment. You deliver complete features, not isolated components.
Building MCP servers and integrationsConnecting agents to client systems through MCP servers and custom integrations. Data in, action out, secure and reliable.
Setting quality standardsTesting, deployment pipelines, security practices. You bring structure where it's needed, without slowing the team down.
Sharing knowledgeYou share what you know with the team. Code reviews, architecture decisions, best practices. No ego, just clarity.
Helping with scopingYou see what is feasible, what is risky and what can wait. On client projects you occasionally weigh in on technical feasibility.

You use AI tools in your daily development work. Claude Code, Cursor or similar tools are not an experiment for you but an accelerator.

Who we are looking for

Must-haves

  • At least 5 years of experience as a full-stack developer
  • Proven experience building robust, secure production applications
  • A strong foundation in security, architecture and DevOps (CI/CD, observability, access control)
  • Strong full-stack TypeScript skills (React/Next.js, Node)
  • Experience with AI engineering: LLMs, agents, RAG, tool use, evals
  • You use AI tools such as Claude Code, Cursor or similar in your daily development work

Nice-to-haves

  • Experience with agent frameworks (Mastra, LangGraph or similar)
  • MCP server development
  • A background in consultancy or client-facing development
  • Professional-level Dutch

The person we are looking for

PragmaticCode or no-code, whatever delivers value fastest. You pick the right tool, not the trendiest one.
Long-term thinker"Where will this system be in a year?" is your default question. You build for the future, not just for the deadline.
Knowledge sharerYou don't hoard knowledge or let ego get in the way. You make the team better by sharing what you know.
Adaptable without compromising qualityFrom client call to refactor and back. Neither suffers.
Good enough is good enoughNot paralysed by perfectionism. You know when something is good enough to ship and when it needs to be better.
OwnershipYou pick up problems without anyone asking. If something is broken, you fix it. If something can be better, you propose it.

Is this your role?

This IS the role for you if...

  • You would rather design architecture than work through tickets
  • You enjoy helping a junior engineer develop their skills
  • You find "how do we keep this secure?" just as interesting as "how do we build this?"
  • You use AI tools in your daily development work and see them as an accelerator, not a threat
  • You want to work in a small team where your choices have a direct impact
  • You would rather build something well than fast, but you know when fast is good enough

This is NOT the role if...

  • You would rather work through tickets someone else has thought up
  • You see security and testing as "someone else's problem"
  • You find it hard to talk to clients about technical choices
  • You prefer working on a large codebase that has been around for years
  • You see AI tools as hype and would rather write everything yourself
  • You are looking for an environment where everything has already been thought out and documented

What do we offer?

Salary€6,800 gross per month (based on full-time)
Hours32-40 hours a week, flexible schedule
EmploymentEmployed or freelance, whichever suits you
Holiday24 days a year (if employed)
WorkplaceA laptop of your choice and your own desk at the office in Amersfoort
ToolingClaude Code, Cursor, and whatever else you need. No debates about licences.
Experiment budgetTime and space to try out new tools, frameworks and approaches
TravelTravel allowance, with travel expenses for occasional client visits reimbursed
LocationHybrid (office at Ruimtevaart 22-24, Amersfoort, and working from home)
AI-first workingA team that gets what you do and why. No need to explain why AI is useful.

There is currently no pension scheme.

The TwoFeetUp office in Amersfoort

The team

This is the technical team you will work with directly.

The humans

Portrait of Wouter van den Bijgaart, Founder & CEO at TwoFeetUpWouterFounder & CEO
Portrait of Sjoerd Tiemensma, Senior AI Engineer at TwoFeetUpSjoerdSenior AI Engineer
Portrait of Lex Zwakenberg, AI Engineer at TwoFeetUpLexAI Engineer
Portrait of Leonie Forsman, Digital Productivity Consultant at TwoFeetUpLeonieDigital Productivity Consultant
Portrait of Roel Winter, AI Consultant at TwoFeetUpRoelAI Consultant
Portrait of Wilfred van Kampen, AI Trainer & Consultant at TwoFeetUpWilfredAI Trainer & Consultant

Daily AI agents (active 24/7)

Internal tools that help the team with specific tasks every day:

Avatar of Duco Declaratie, For all the receiptsDuco DeclaratieFor all the receipts
Avatar of Stella Story, Our storytellerStella StoryOur storyteller
Avatar of Pieter Post, Automated mail handlingPieter PostAutomated mail handling

The process

1

Send your portfolio or GitHub

Send your CV and preferably a portfolio or GitHub profile. Show what you have built, why you made those choices and what you learned from them. We prefer that to a polished cover letter.

2

Culture-fit interview

An interview with Wouter (CEO). No technical questions, but: who are you, how do you work, and does that fit the way we work?

3

Technical interview with Sjoerd

An in-depth conversation with Sjoerd (Senior AI Engineer) about architecture, security and how you write code that stays maintainable over time. No whiteboard test, just a real conversation.

Sound like you?

Then we'd love to hear from you. No formal cover letter needed: just tell us who you are and why this suits you.

Apply now

Or email: jobs@twofeetup.com

Don't see a suitable role? Have an idea for how you could contribute?

Send an open application to jobs@twofeetup.com. We're always keen to hear from people who could strengthen our team.

Book a call