Model Behavior Engineer (AI)

Location: Remote in North America; requires 4+ hours of overlap with team members in the Eastern Time Zone.

Annual salary: $200,000–$275,000 USD, plus equity and benefits.

Company

Builds a browser designed to help people organize their lives, create, and explore the internet, including the Dia AI browser experience.

What you will do

• Define Dia’s intended AI behavior and choose between prompt changes, tools, models, agent harnesses, evaluation improvements, or product specifications.
• Ship prompt, code, and data changes continuously, with multiple pull requests each week.
• Design and own evaluations that make AI quality and cost measurable over time.
• Identify slow or manual workflows and build internal tooling with engineering partners to support iteration at scale.
• Test new models and harnesses and prototype AI architecture strategies for production use.
• Work end to end with engineering and product, from understanding user needs through shipping and validating results.

Requirements

• 4+ years of experience in product, design, or an adjacent hands-on builder role.
• Experience taking a product from concept to its initial release.
• Ability to break ambiguous problems into measurable systems and design evaluations to guide improvements.
• Daily hands-on use of AI tools such as Codex, Claude Code, or Cursor, with clear reasoning about tooling choices.
• Interest in an individual contributor role involving prompts, code, data, and multiple weekly pull requests.
• Availability in North American time zones with 4+ hours of overlap with Eastern Time.

Nice to have

• Previous founder experience.

Culture & Benefits

• Remote-first, distributed team of close to 100 people.
• Full-time compensation includes base salary, equity, and benefits.
• Option to work from the office in Williamsburg, Brooklyn, New York.
• Focus on diversity and perspectives from people with different backgrounds and experiences.
• Work on a small, high-output Model Behavior team focused on AI product development.