Senior Full Stack Engineer (AI & Platform Innovation)

LegionellaDossier; Amsterdam; On-site; EUR 70,000 - 90,000; Full time

Benefits offered by this job

Freedom to experiment and innovate

Strong engineering culture

Job summary

LegionellaDossier in Amsterdam is seeking a Senior Engineer to develop AI-heavy product features and solidify the technical foundation. You will focus on building full stack applications and managing self-hosted LLM infrastructure, driving innovation in water safety compliance.

The ideal candidate should have extensive experience with Node.js, Next.js, and LLMs, and be excited about working on a rapidly evolving platform with a strong engineering culture.

Qualifications

• Strong experience with Node.js and modern TypeScript ecosystems.
• Experience with Next.js and modern frontend architecture.
• Experience working with LLMs, embeddings, and AI agents.
• Understanding of GPU workloads and inference optimization.

Responsibilities

• Design and build full stack applications using Node.js and Next.js.
• Develop AI-native product experiences.
• Implement and manage self-hosted LLM infrastructure.
• Experiment with different open-source and commercial models.
• Build AI orchestration layers and intelligent workflows.

Skills

Node.js

Next.js

AI systems

TypeScript

Kubernetes

GPU workloads

Model quality evaluation

Self-hosted models

Job description

Node.js / Next.js / Self-Hosted LLMs / AI Systems

BriqSafe (currently operating as LegionellaDossier) is the Netherlands' leading SaaS platform for water safety compliance.

Since our founding in 2015, we've grown to a team of 30+ professionals in Utrecht, helping organizations across the Netherlands and the UK manage, automate, and prove compliance around water safety. We're now expanding into Spain and beyond, with a clear ambition: become the global market leader within the next five years.

Our platform is undergoing a complete transformation, replacing our legacy system with a modern, scalable architecture built on microservices, event-driven communication, and a far more intelligent feature set.

We are not looking for someone who simply integrates APIs or ships CRUD features. We are looking for an engineer who thinks AI-first by default. Someone who understands that modern software development is shifting from traditional applications toward intelligent systems, autonomous workflows, AI-assisted operations, and model-driven product experiences. Someone who gets excited about building the infrastructure and product capabilities that will define the next generation of SaaS.

The Role

You will play a key role in building AI-heavy product features and the technical foundation behind them. This includes:

• Designing and building full stack applications using Node.js and Next.js
• Developing AI-native product experiences
• Implementing and managing self-hosted LLM infrastructure
• Experimenting with different open-source and commercial models
• Optimizing inference performance, scalability, and operational costs
• Evaluating which models perform best for specific use cases
• Building AI orchestration layers and intelligent workflows
• Creating systems that combine automation, context-awareness, and real-world operational data
• Working closely with product and engineering leadership on long-term platform strategy

This is not a "bolt AI onto an existing app" role. AI will become part of the core platform architecture.

What you’ll do

We are looking for a senior engineer with strong product intuition and a deep curiosity for modern AI systems. You should have:

• Strong experience with Node.js and modern TypeScript ecosystems
• Experience with Next.js and modern frontend architecture
• A full stack mindset and the ability to own features end-to-end
• Experience working with LLMs, embeddings, RAG pipelines, or AI agents
• Knowledge of self-hosted/open-source models such as Llama, Mistral, DeepSeek, Qwen, or similar
• Understanding of GPU workloads, inference optimization, and AI infrastructure tradeoffs
• Experience comparing model quality, latency, and operational cost
• A strong engineering mindset focused on scalability, maintainability, and performance
• The ability to move fast without creating chaos
• Curiosity and obsession with where software engineering is heading next

Bonus points if you:

• Have experience with Kubernetes or cloud-native infrastructure
• Have worked with vector databases and retrieval systems
• Have built AI copilots, autonomous workflows, or internal AI tooling
• Have experience fine-tuning or evaluating models
• Have opinions about when not to use AI

What you bring

• You are the kind of engineer who:
  • Experiments with new AI tooling before it becomes mainstream
  • Thinks beyond tickets and sees platform opportunities
  • Questions old assumptions and outdated architectures
  • Likes solving hard technical problems
  • Understands the balance between innovation and pragmatism
  • Wants to help shape the direction of a rapidly scaling platform
• You probably spend time reading about:
  • Open-source LLM ecosystems
  • AI infrastructure
  • Agentic workflows
  • Retrieval systems
  • Inference optimization
  • AI developer tooling
  • Emerging platform architectures
• And you probably already have side projects involving AI.

What we offer

• The opportunity to build AI-first systems from the ground up
• Real ownership and influence on technical direction
• A rapidly growing international SaaS platform
• Complex technical challenges with real-world impact
• Freedom to experiment and innovate
• A strong engineering culture focused on building scalable systems
• The chance to help define the next evolution of BriqSafe

  We are moving fast. The platform is expanding internationally, new verticals are being launched, and AI is becoming a foundational part of how we build products and operate internally. If that excites you, we should talk.