Inflection AI
Principal Research Engineer, Model Training & Post-Training
$400K–$550K
Palo Alto, California, United States · Principal · Full-time · Posted Jun 29, 2026
- Education
- PhD in Computer Science, Machine Learning, Artificial Intelligence, or a related field, or equivalent practical experience.
- Visa sponsorship
- Support of country-specific visa needs for international employees living in the Bay Area
About the job
Leads the end-to-end model-improvement program, from data and training through evaluation, release, and production feedback, to deliver measurably better models for users.
What you'll do
- Own the roadmap for model capability, reliability, safety, performance, and enterprise readiness; lead training and post-training strategy.
- Direct large-scale distributed training and make model architecture, optimization, and data strategy decisions.
- Build evaluation and release-quality systems, improve training infrastructure, and debug model behavior through production feedback.
What they ask for
- Led or was a principal contributor to large-scale LLM, multimodal, or foundation-model training or post-training programs.
- Deep experience with transformer-based models, hybrid architectures, deep-learning frameworks, and distributed training systems.
- Practical experience with post-training and alignment methods such as SFT, RLHF, DPO, GRPO, RLAIF, reward modeling, or preference optimization.
- Experience with large-scale training infrastructure; PhD in a related field or equivalent practical experience.
Nice to have
- Experience with GPU clusters at the scale of 1,000+ GPUs.
Pay
$400,000 to $550,000 USD annual base salary
Tools
SFT, RLHF, DPO, GRPO, RLAIF, GPU
AI focus
Leads foundation-model training and post-training, alignment, evaluation, safety, and production improvement.
Model-written summary · the original posting is authoritative