ReflectionAI

Forward Deployed Engineer - LLM Post-training

San Francisco

H1B sponsorship availableDetected 92 days ago

PythonMachine LearningData EngineeringData ScienceLLMsResearch

About the role

This team takes Reflection's open-weight models and adapts them for specific customer domains, tasks, and constraints.
You'll work directly with customers to understand what they need and with research teams to push what's possible.

Prepare training data from raw customer inputs: inspect data quality, clean and format datasets, identify adversarial or noisy samples, and build reproducible data pipelines.
Understanding of evaluation methodology: how to design evals, interpret training graphs, and tell whether a model is actually better or just overfitting to the benchmark.
Sponsorship support: We sponsor visas to help exceptional talent join our team and support long-term immigration pathways where applicable.
Team building: We have regular off-sites, happy hours, and team celebrations.
Joining Reflection means building from the ground up as part of a talent-dense team.

Applied ML experience with hands-on fine-tuning of language models.
You have prepared datasets, run training loops, evaluated results, and shipped a fine-tuned model.
Familiarity with SFT, DPO, RLHF, or similar techniques.
Comfort with training infrastructure: GPUs, compute management, debugging common training failures.
Experience with data pipelines and version control for datasets and experiments.
3+ years of engineering experience with meaningful exposure to applied ML or ML engineering (e.g., MLE, Applied Scientist, Data Scientist who shipped models to production, or ML-focused SWE).

Salary and equity structured to recognize and retain our talent globally.
Health & wellness: Comprehensive medical, dental, vision, and life, with an annual wellness allowance.

Top-tier compensation: Salary and equity structured to recognize and retain our talent globally.
Stock options: Everyone who joins and contributes to Reflection's success gets to share in the upside through stock options.
Health & wellness: Comprehensive medical, dental, vision, and life, with an annual wellness allowance.
Life & family: 22 weeks paid parental leave for all new birthing and non-birthing parents, including adoptive and surrogate journeys.
Vacation days: Unlimited paid time off in the U.S. and 30 days in the U.K.

make intelligence open and accessible to all.
We're looking for a core member of Reflection's Applied AI team to drive model fine-tuning and evaluations for enterprise customers.
As a ML Engineer, you will work hands-on with customer data, run fine-tuning workflows, build evaluation harnesses, and deploy adapted models to production.
Reflection is a research lab making intelligence open and accessible for everyone to use, customize, and build on.
We build open models that let anyone control their intelligence and help shape the future of AI.
Role Overview
Build and maintain evaluation infrastructure: design eval suites, curate test sets, establish baselines, and measure whether fine-tuned models actually improve on the tasks customers care about.
Contribute to evolving playbooks, evaluation benchmarks, and best practices as part of a growing fine-tuning and evals practice.
What We're Looking For

We sponsor visas to help exceptional talent join our team and support long-term immigration pathways where applicable.

This listing is sourced directly from ReflectionAI's careers page and normalized into a canonical job model.