Senior AI & Agent Platform Engineer

Justworks; España; Presencial; EUR 111.000 - 143.000; Jornada completa

Descripción de la vacante

Justworks is seeking a Senior Software Engineer to join a small, highly autonomous cross-functional team building AI-native systems in a product environment. You will own large sections of the technology stack, make pragmatic decisions in evolving territory, and ship production-ready systems relied on by users daily.

You will help build an agent platform that scales knowledge and reasoning rather than solely writing bespoke code, spanning LLM-powered design, backend services, tool integrations,

Formación

• 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

Responsabilidades

• 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.

Conocimientos

Backend engineering

LLMs & AI agents

API design

Product mindset

Ownership

Descripción del empleo

Justworks is seeking a Senior Software Engineer to join a small, highly autonomous cross-functional team building AI-native systems in a product environment. You will own large sections of the technology stack, make pragmatic decisions in evolving territory, and ship production-ready systems relied on by users daily.

You will help build an agent platform that scales knowledge and reasoning rather than solely writing bespoke code, spanning LLM-powered design, backend services, tool integrations,