Senior AI Engineer - AI Frontiers

Who We Are

At Justworks, you’ll enjoy a welcoming and casual environment, great benefits, wellness program offerings, company retreats, and the ability to interact with and learn from leaders in the startup community. We work hard and care about our most prized asset - our people. We’re helping businesses get off the ground by enabling them to focus on running their business. We solve HR issues. We’re data-driven and never stop iterating. If you’d like to work in a supportive, entrepreneurial environment, are interested in building something meaningful and having fun while doing it, we’d love to hear from you. We're united by shared goals and shared motivations at Justworks. These are best summed up in our company values, which are reflected in our product and in our team.

Department

Technology, AI Frontiers

About The Team

The Data & Analytics team is Justworks' data and AI center of excellence — a connected set of functions spanning business intelligence, data science, analytics engineering, platform data/ML engineering and AI builders. We've grown significantly over the last several years and continue to build momentum across the business, leveling up maturity in how we deliver insights, govern data, and enable the company to make better decisions. You'll find a highly collaborative & diverse group motivated by craft, shared learning, and a genuine commitment to growing our impact for customers while evolving how we work together for our people. Come build with us!

Who You Are

You're an engineer who gets energized by hard problems that don't have a predetermined solution — and you know how to ship your way to an answer. You've built production systems, navigated real infrastructure, and learned to move fast without leaving a mess. You pick up new domains quickly and use that understanding to build solutions that fit. You see frontier AI not as something you're experimenting with but as the means by which we transform an org. You're insatiably curious, never satisfied leaving a system the way you found it, and you know how to evaluate whether an AI system is actually working — not just whether it runs. Impact matters more to you than the tools you used to get there; you center the customer even when you're building internal tooling. Justworks is looking for a Senior AI Engineer to join AI Frontiers, a small internal consultancy that finds where AI creates step-change improvements across the company — builds the thing, gets it to production, and transfers it to the team that will own it. You'll move across business functions as a functional accelerator, resolve AI-specific systems gaps nobody else is moving on, and read what's emerging externally before it becomes obvious inside. You build, prove the pattern, and hand off. Technical execution is table stakes. The harder skill is navigating ownership, alignment, and organizational complexity while still shipping.

What You Will Work On

• Drop into business functions to identify where AI has the highest leverage, define what to build, and own the full arc from scoping through handoff
• Spot and resolve AI-specific systems gaps across the org - missing shared infrastructure, fragmented adoption patterns, absent measurement benchmarks - and move on them faster than the rest of the org could
• Scan externally for emerging AI capabilities and market patterns; translate signal into written briefs that inform what the team experiments on next
• Build AI-powered tools and pipelines using frontier models, agent frameworks, and LLM infrastructure as core building blocks, not experiments
• Design and implement evaluation frameworks (evals) to measure whether AI systems are performing as intended — not just technically functional but meaningfully useful
• Instrument AI systems for observability: logging, tracing, cost tracking, latency monitoring, and anomaly detection using tools like Datadog, LangSmith, or equivalent
• Navigate cross-functional ownership dynamics: identify the right stakeholders, build alignment, and hand off in a way that sticks
• Represent AI Frontiers in cross-functional forums and executive reviews as a credible voice on what AI can and can't do
• Perform other related responsibilities as needed based on department and/or organizational needs

Qualifications

• 6+ years of professional hands-on software engineering experience
• Full-stack or backend engineering depth - shipped and maintained production systems, not just prototypes
• 2+ years, hands-on experience building with LLMs and AI tooling in production: agent frameworks, pipelines, retrieval systems, or AI-integrated workflows that real users depend on
• Experience designing and running evals: you know how to define what "working" means for an AI system and build the measurement scaffolding to prove it
• Familiarity with LLM observability tooling (LangSmith, Datadog LLM monitoring, or equivalent): you instrument what you build and use signal to improve it
• Track record of working across functions: partnered with non-engineering stakeholders, understood their problem do