Staff AI/Machine Learning Engineer

Role Description

As a Staff AI Engineer at Tonic, you'll own the models that make Tonic's data trustworthy:

• Train the synthesis models that replace sensitive data with something realistic enough to stay useful downstream.
• Develop NER systems that detect sensitive data across legal, clinical, and enterprise text.
• Build synthetic environments for agent training and evaluation.
• Create evaluation infrastructure that separates frontier models instead of relying on saturated benchmarks.
• Work with customer environments handling genuinely sensitive data, ensuring high standards of accuracy.
• Partner with labs and enterprise teams to ship AI safely.

What You'll Do

• Design and build systems for generating longitudinally coherent synthetic environments, including persona modeling and task generators.
• Build and maintain synthesis models that generate realistic replacement values at large scale.
• Train and improve NER models for entity detection across various data types.
• Build evaluation infrastructure that grades agent outcomes and produces real discrimination between models.
• Fine-tune and evaluate open-weight models on Tonic-generated data.
• Expand coverage into new domains, languages, and entity types.
• Own model evaluation across precision, recall, and utility preservation.
• Optimize inference for efficient model performance on sensitive data.
• Partner with frontier labs and enterprise ML teams to improve models.
• Set technical direction for a small, senior team.

Qualifications

• 8+ years (or PhD with 3+ years) building production ML systems.
• Hands-on experience training and shipping models to production.
• Experience with generative or synthesis models where output fidelity and downstream utility matter.
• Strong software engineering fundamentals.
• Fluency with modern training and evaluation stacks (PyTorch, distributed training).
• Comfort working with messy, sensitive, real-world data.
• A track record of framing ambiguous problems and driving them to measurable results.
• Bonus: experience in synthetic data generation, data privacy, or benchmark construction.

Benefits

• Competitive salary and equity
• Unlimited paid time off
• 401k plan with employer contribution
• Medical, dental, and vision insurance
• Generous parental leave policy
• Remote-friendly work environment