Forward Deployed Engineer, Lead - LLM Post-training

Role Overview We're seeking an exceptional technical leader to build and scale Reflection's post-training and evaluation capabilities within the Applied AI team. This team works at the intersection of model adaptation, sovereign deployment, and enterprise deployment: taking Reflection's open-weight models and making them work for specific customer domains, tasks, and constraints. As a Forward Deployed Engineer Lead, Post-Training, you will own the end-to-end technical strategy for model customization, from synthetic data generation and reward modeling through training and production deployment. You will work directly with customers to understand their needs and with research teams to push what's possible with our models.

What you'll do:

• Lead post-training engagements with enterprise customers: assess their data, define training strategies, design reward signals and verifiers, prepare datasets, run training loops, and evaluate results against customer-specific benchmarks.
• Design and build RL training environments for model adaptation, including synthetic data generation pipelines, reward model training, and preference data collection workflows.
• Design and build evaluation infrastructure: define what "better" means for each customer use case, build eval harnesses, curate test sets, and establish baselines that measure real-world performance.
• Own the data pipeline from raw customer data through training-ready datasets, including synthetic data generation, data quality inspection, cleaning, and format standardization.
• Deploy post-trained models across hybrid environments (public cloud, VPC, and on-premises), working with infrastructure teams to ensure inference performance, cost efficiency, and reliability at scale.
• Shape and scale the post-training and evaluation practice by defining playbooks, best practices, and technical standards. Mentor engineers on the team and help define what great applied AI work looks like at Reflection.

Full details and application on the official Reflection AI careers page.