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Cognition

Research Engineer, Post-Training

San FranciscofulltimemidAdded today

About this role

Join an applied AI lab as a Research Engineer focused on post-training systems for Devin, an AI software engineer. You'll develop training recipes, design evaluations, and advance alignment techniques that determine how AI agents learn and behave in real-world tasks.

What you'll do

  • Iterate on post-training datasets, training stages, and hyperparameters to optimize model behavior across evaluations and production
  • Design and maintain evaluation frameworks that capture meaningful performance metrics and catch capability gaps
  • Investigate unexpected training results to understand root causes and apply insights to future improvements
  • Implement and advance alignment techniques including RLHF, RLAIF, and constitutional approaches for long-horizon agent tasks
  • Analyze scaling relationships between data, compute, and performance; develop new methodologies when existing approaches plateau
  • Bridge research and engineering by moving from prototypes to deployed systems with minimal process overhead

What they're looking for

  • Post-training methods (RLHF, RLAIF, preference modeling, reward learning)
  • Probability, statistics, and machine learning theory
  • Large-scale distributed training and debugging
  • Experimental design and statistical analysis for distinguishing signal from noise
  • Systems-level thinking across training pipelines, data, and evaluation
  • Python and deep learning frameworks
  • Ability to work in ambiguous, fast-moving research environments

Benefits

  • Frontier-scale compute resources with GPU allocations available from day one
  • Small, highly selective team where research directly impacts product deployment
  • Minimal bureaucracy with emphasis on speed and technical autonomy
  • Work on one of the most competitive problems in AI
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Cognition

Cognition builds AI software engineers and developer tools, including Devin (an AI software engineer) and Windsurf (an AI-native IDE) that help developers automate tasks and write code more efficiently. The company is hiring Deployed Engineers to work directly with customers on adoption and integration, SREs to manage production reliability and infrastructure, federal engineers for government deployments, and IT specialists to support internal operations.

View all jobs at Cognition

Likely interview questions

  • Describe a time you advanced an ML system through post-training or alignment work—what was your process for measuring success?
  • Walk us through how you've debugged a large-scale distributed training run; what unexpected issues did you encounter?