Researcher, Post Training

About the role

The next leap in model intelligence won’t come from scale alone — it will come from better post-training and alignment. Cartesia’s Post-Training team is developing the methods and systems that make multimodal models truly adaptive, aligned, and grounded in human intent. As a Researcher on the Post-Training team, you’ll work at the intersection of machine learning research, alignment, and infrastructure, designing new techniques for preference optimization, model evaluation, and feedback-driven learning.

You’ll explore how feedback signals can guide models to reason more effectively across modalities, and you’ll build the infrastructure to measure and improve these behaviors at scale. Your work will directly shape how Cartesia’s foundation models learn, improve, and ultimately connect with people.

Responsibilities

• Own research initiatives to improve the alignment and capabilities of multimodal models
• Design and implement new post-training methods and evaluation frameworks to measure model improvement
• Partner closely with research, product, and platform teams to define best practices for creating specialized models
• Implement, debug, and scale experimental systems to ensure reliability and reproducibility across training runs
• Translate research findings into production-ready systems that enhance model reasoning, consistency, and human alignment

Requirements

• Deep knowledge of preference optimization and alignment methods, including RLHF and related approaches
• Experience designing evaluations and metrics for generative or multimodal models
• Strong engineering and debugging skills, with experience building or scaling complex ML systems
• Ability to trace and diagnose complex behaviors in model performance across the training and evaluation pipeline

Qualifications

• Nice-to-haves: Experience with multimodal model training (e.g., text, audio, or vision-language models), contributions to alignment research or open-source projects related to model evaluation or fine-tuning, background in designing or implementing human-in-the-loop evaluation systems

Skills

• Strong programming skills in Python or equivalent
• Experience with machine learning frameworks such as TensorFlow, PyTorch, or similar
• Knowledge of reinforcement learning and/or reward modeling
• Experience with natural language processing and/or computer vision

Benefits

• Competitive base salary alongside attractive equity package
• Fully covered medical insurance along with dental and vision for you and your family
• 9 weeks paternity & 12 weeks maternity leave
• 401(k)
• Monthly stipend for commuting to the office
• Flexible PTO
• Lunch, dinner, and plenty of snacks provided daily

Pay

Competitive base salary alongside attractive equity package.

Schedule

We are an in-person team based out of offices in 🇺🇸 San Francisco, 🇬🇧 London and 🇮🇳 Bangalore. We love being in the office, hanging out together, and learning from each other every day.

Note

Cartesia participates in E-Verify and will provide the federal government with Form I-9 information to confirm employment eligibility after hire.