Founding Machine Learning Engineer (ML Research Engineer)

Posted for Willow on behalf of Oak Recruiting. Founding Machine Learning Engineer (ML Research Engineer), full-time, in person in San Francisco, CA. $150K - $250K base plus equity.

Location: San Francisco, CA. In-person team. You must live in the SF Bay Area or be open to relocating to San Francisco.

Compensation: $150,000 - $250,000 base plus meaningful early-stage equity.

Work authorization: Unfortunately, visa sponsorship and visa transfers are not offered for this role. Applicants must be authorized to work in the US without sponsorship, now and in the future.

About Willow

Willow is a voice-first productivity app that lets you type anywhere on your computer using your voice. People rely on Willow every day to write emails, respond in Slack, prompt AI, take notes, and move faster through their work.

Willow has proven adoption from individual power users to enterprises like Uber, Gusto, and Heidi Health, and is backed by Y Combinator, Box Group, and founders from Instacart, Reddit, Shopify, and HubSpot. The company is scaling quickly, and you will be joining early.

The Role

Willow is looking for a Founding ML Research Engineer to build its personalization layer.

This role is for someone who believes the hardest unsolved problem in AI products is not raw model capability, but context and user modeling. Foundation models are getting better every month. The open question is how to build an AI system that understands a specific user in the flow of their work.

You will work on the systems that turn Willow from "great dictation" into a personalized communication and intent layer. Today, a user can say something rough like: "Tell my boss I'll come in at 6." Willow should understand the screen, the relationship, the app, the user's tone, their past edits, their communication style, and produce the message the user would have written if they had taken the time to write it well.

What You'll Work On

This is not a pure research role and not a generic ML infra role. You should be excited to take ambiguous ideas, ship quickly, learn from real-world usage, and iterate aggressively.

What We're Looking For

You are unusually excited by personalization, context, workflows, and user modeling. You think deeply about questions like: How does an AI system learn what a user actually means? How do you build systems that feel genuinely personalized instead of generically helpful? How do you evaluate trust?

You probably have some combination of:

Willow cares much more about technical depth, product intuition, and speed than credentials or years of experience.

Why This Matters

The first major computer interface was the keyboard. The second was touch. The third is voice. But the opportunity is larger than voice itself. Voice captures intent naturally and with very low friction. By living directly inside user workflows, Willow gains something most AI systems do not have: continuous, real-world context. As AI systems become more autonomous, the highest-frequency interactions on a computer remain fast, contextual, ambiguous, and deeply personal. That requires understanding not just the task, but the user: their workflows, preferences, communication patterns, and intent in the moment. Exactly what Willow can capture.

Willow is an intense, highly ambitious, in-person team in San Francisco that optimizes for learning, ownership, speed, and exceptional work. You will have significant responsibility, direct ownership, and the opportunity to shape the future direction of the company very early.

Excited? Apply here or reach out to Rachel at [email protected]!