Principal Engineer, Fin AI Agent

Fin is the AI Customer Agent company on a mission to help businesses provide perfect customer experiences. Our AI Agent Fin is the highest‑performing AI Customer Agent on the market today, enabling businesses to deliver impeccable, always‑on customer support across the customer journey – from service, to sales, to ecommerce. Powered by our own AI models, Fin resolves complex customer issues end‑to‑end across every channel, with minimal set‑up and integration.

Founded in 2011, Fin became one of the fastest growing companies and remains one of the largest private software companies in the world with nearly 30,000 global businesses using our products to transform their customer support. Driven by our core values, we push boundaries, build with speed and intensity, and relentlessly deliver incredible value to our customers.

Fin is the #1 AI agent for customer service. It resolves over 1M customer conversations every week, and we’re just getting started. We’re on the cutting edge of defining how AI agents should work — inventing paradigms that didn’t exist six months ago and discovering entirely new problem spaces every time we push the technology further.

This role sits at the heart of the Service Agent pillar — 12 teams and growing, building every capability that makes Fin work. You’ll partner at the strategic pillar level: broad context across work streams, deep technical understanding of how Fin operates end‑to‑end, and the autonomy to decide where you need to go next.

When we need a new work stream spun up from scratch — a brand new team, an ambiguous problem space, aggressive timelines — you’re the person who makes that happen. The competitive landscape is intense. Fast‑moving AI‑native startups are coming hard for this space, shipping aggressively and going after the same deals we are. We need someone who thrives under that pressure, who can maintain technical excellence while moving at startup speed within a company that has the resources and customer base to make that speed count.

What will you do?

• Partner at the strategic pillar level. You’ll have broad context across work streams and use that to inform technical strategy and investment priorities.
• Spin up 0‑to‑1 work streams. Bring together engineers who’ve never worked as a team, disambiguate the problem space, build momentum under aggressive timelines, set high expectations, and drive execution.
• Execute on the most ambiguous, highest‑stakes problems. You’re hands‑on. You write code, you ship features, you’re deep in the weeds.
• Lead experimental work at the AI frontier. Run your own A/B tests, do prompt engineering, build evals, and calibrate accuracy, cost, and latency for LLM‑powered features.
• Shape long‑term technical strategy through execution. Your hands‑on work informs the architecture.
• Work across the full stack in an AI‑first development environment.
• Raise the bar for the people around you. Give direct, actionable feedback that changes outcomes.

What are we looking for?

• The core requirement: engineering depth and product thinking. We need someone who combines deep engineering ability with strong product and design instincts.
• Operated at real scale and has builder energy. You’ve likely spent time at companies operating at significant scale.
• AI fluency. You’re actively experimenting with AI‑assisted development.
• Deep technical depth with breadth. You can go deep into the weeds on at least one technical domain.
• Communication as a superpower. You can explain to leadership why a technical investment matters.
• Extreme autonomy. You partner with the Engineering Director on where you think the pillar needs to go next.
• Critical thinking about the business. You understand what Fin is optimizing for and translate that into technical decisions.
• At least ~10+ years of experience, with significant time as a technical leader driving complex projects across multiple teams and stakeholders.
• Stack agnostic. We use Ruby on Rails, React (migrating from Ember), and AWS.

Why Fin, why now?

Fin is #1 — and the race is heating up. We built the leading AI agent for customer service, but fast‑moving AI‑native startups are coming for this space. This is one of the most consequential competitive moments in tech history, and the engineering decisions made in the next 12 months will determine who wins.

A rare pivot that actually worked. Fin has been building for 15 years — deep product, massive customer base, strong revenue. But unlike most legacy SaaS companies, we made a successful pivot to AI. While most of SaaS trends down, Fin trends up.