Senior AI-Native Backend Engineer

Justworks; Netherlands; On-site; EUR 143,000 - 184,000; Full time

Job summary

Justworks is seeking a Senior Software Engineer in the Netherlands to build AI-native agent platforms. You will own large segments of the technology stack, design scalable backend systems, and ship production-ready software that improves operations at scale.

You’ll work on LLM-powered agent design, robust backend services, tool integrations, and knowledge infrastructure, collaborating with a small, autonomous team to deliver reliable, auditable AI-driven workflows.

Qualifications

• 5+ years of backend engineering experience building and operating production systems.
• Hands-on experience with LLMs and AI agents (orchestration, RAG, tool/function calling, or similar)
• Strong API design and system integration skills
• Product-minded: questions requirements and contributes to product decisions, not just execution
• Proven ownership of complex projects in ambiguous, early-stage environments

Responsibilities

• Design, build, and own core components of the agent platform, from the orchestration layer to the tool integrations connecting it to internal systems.
• Build and evolve the capabilities layer: APIs, data access patterns, and service integrations for agents to execute operational workflows.
• Architect the knowledge and memory infrastructure, allowing agents to retrieve the data and act across our systems.
• Design and implement the trust and safety framework, including audit trails, human-in-the-loop controls, and guardrails for safe and auditable AI-driven operations.
• Contribute to agent evaluation and testing infrastructure, defining how we measure accuracy, reliability, and regression across agent behaviors.
• Partner directly with Operations to understand workflows, identify automation opportunities, and translate process knowledge into agent capabilities.
• Mentor other engineers on the team as it grows.

Skills

Backend engineering

LLMs & AI agents

API design

System integration

Ownership mindset

Job description

Justworks is seeking a Senior Software Engineer in the Netherlands to build AI-native agent platforms. You will own large segments of the technology stack, design scalable backend systems, and ship production-ready software that improves operations at scale.

You’ll work on LLM-powered agent design, robust backend services, tool integrations, and knowledge infrastructure, collaborating with a small, autonomous team to deliver reliable, auditable AI-driven workflows.