About AfterQuery

AfterQuery is an applied research lab curating data solutions for foundation model development. We serve every frontier AI lab with the mission of delivering the best data to power the best models. In doing so, we can make expertise that once took a lifetime to build available to anyone who needs it. Our customers are the ones building the foundation models themselves and our work sits directly in the loop of how those systems improve. This is a rare opportunity to join a company at a defining moment in AI. Since raising our $30M Series A at a $300M valuation, AfterQuery has grown well over a $100M revenue run rate. We're based in San Francisco and backed by leading investors including Altos Ventures, BoxGroup, and Y Combinator and angels from Google DeepMind, OpenAI, Anthropic, Meta Superintelligence Labs, and Microsoft AI.

Why Apply

• Massive Opportunity: We are one of the fastest-growing YC companies in our batch, and we believe we can become one of the fastest-growing YC companies of all time.
• Founding Impact: You will own and architect core infrastructure systems that power our platform from the ground up.
• Equity & Growth: Competitive salary and meaningful equity. As we scale, you’ll have the opportunity to shape the engineering organization and lead major technical initiatives.
• Strong Team: Our founding team has experience from Citadel Securities, Meta, Google, Silver Lake, and Morgan Stanley — work alongside world-class engineers and researchers.

Key Responsibilities

Final Quality Review: Own the last quality checkpoint before datasets are delivered or published, auditing outputs (including code, technical, and reasoning data) for correctness, clarity, structure, and adherence to spec.

QC Process & Tooling: Work with infrastructure engineers to continuously automate and improve QC workflows

Cross-Functional Feedback Loop: Partner with data delivery teams to identify systemic quality issues, feed corrections back into contributor training, and prevent recurrence.

Metrics & Reporting: Own quality metrics and KPIs, reporting on error rates, root causes, and improvement trends to company leadership.

Operational Support: Contribute to company-wide initiatives across building, analysis, coordination, and execution as AfterQuery scales.

Required Qualifications

• 3+ years of experience in a technical role (software engineering, data science, ML engineering, or similar) with hands-on proficiency in at least one modern programming language
• Proven ability to review, debug, and evaluate both code and technical data and knowledge work data for correctness, structure, and quality; demonstrated rigor in reviewing others' work
• Experience building or leading a quality assurance/quality control function, ideally for a technical or data-centric product
• Extremely high attention to detail and comfort making judgment calls on ambiguous or contested technical content
• Strong leadership and communication skills; able to translate technical quality issues into clear, actionable feedback across a distributed team
• High agency and strong work ethic; comfort operating with minimal direction in ambiguous, fast-moving environments
• Genuine passion for AI and an entrepreneurial inclination
• Demonstrated competitive success

Preferred Qualifications

• Experience in AI training data, RLHF, or data-annotation quality assurance
• Background reviewing datasets across multiple domains (code, reasoning, knowledge work)
• Experience designing rubrics, grading criteria, or automated quality-check tooling/scripts
• Familiarity with Claude Code or similar AI-assisted workflow tools
• Computer science degree or equivalent hands-on engineering background

Company Benefits (For Eligible Employees):

• Health Insurance: Medical, Vision, Dental
• 401(k) with Employer Match
• Daily Meals: Daily UberEats Stipend
• Monthly Wellness Stipend
• Commute Covered

We are an equal opportunity employer committed to providing a workplace free from discrimination and harassment. Employment decisions are made without regard to legally protected characteristics under applicable federal, state, or local law. We comply with applicable pay transparency requirements and provide compensation ranges based on the position, qualifications, experience, and other relevant factors. Reasonable accommodations are available to qualified individuals with disabilities and for sincerely held religious beliefs, as required by law. This job description is intended to describe the general nature and level of work performed and is not an exhaustive list of all duties, responsibilities, qualifications, or working conditions associated with the position. We reserve the right to modify this job description as business needs change.