Tessera Labs
Research Engineer
$200K–$300K
San Jose Office (HQ) +1 · Full-time · Posted Aug 21, 2026
- Location
- San Jose Office (HQ)
New York City Office - Experience
- Significant language-model training, fine-tuning, or post-training experience; no years specified.
About the job
Builds and scales post-training, reinforcement-learning, evaluation, and inference systems to adapt language models for long-horizon work on enterprise systems and deploy successful models to production.
What you'll do
- Build post-training stacks, RL environments, data pipelines, and memory/context systems for long-horizon agents.
- Develop representation layers and reproducible evaluation infrastructure; design, run, and analyze experiments.
- Optimize training and inference, and move model results into production serving.
What they ask for
- Significant experience training, fine-tuning, or post-training language models, with results owned; RL tuning experience is close to a requirement.
- Strong software engineering fundamentals and fluency in Python and PyTorch (or JAX).
- Ability to design, run, and interpret experiments with empirical rigor.
- Experience with GPU infrastructure at scale.
Nice to have
- Experience building RL environments, execution sandboxes, or verifiable-reward task suites.
- Experience with long-context modeling, knowledge graphs or ontologies, agent memory systems, code models, or open-source ML systems.
Pay
$200K – $300K (base salary; compensation type not stated)
Tools
Python, PyTorch, JAX, vLLM, SGLang, Triton, DeepSpeed, Ray
AI focus
Post-trains open-weight models, especially with reinforcement learning, to perform long-horizon enterprise-system tasks; builds agent memory, environments, evaluations, and production inference systems.
Model-written summary · the original posting is authoritative