Machine Learning Engineer

Arena

Senior Machine Learning Engineer scaling and strengthening core infrastructure for real-world AI evaluation. Collaborating with researchers and engineers to build and improve model benchmarking systems.

Posted 4/12/2026full-timeBay Area • California • 🇺🇸 United StatesMid-LevelSeniorWebsite

About the role

Key responsibilities & impact

Architect and build what will become our core modeling for data and evaluation products
Own the full stack data, model training, and eval pipelines
Help grow a culture of feedback and rapid product iteration as we build new features as a tight-knit team
Conduct research into state-of-the-art evaluation methods and contribute to the long-term vision for a centralized, scalable evaluation platform.

Requirements

What you’ll need

Strong programming skills with the ability to work across the stack in a typical recommendation system or LLM stack
Experience in deep learning, language models or reward model training
Experience in working with LLM for fine tuning, prompt engineering, function calling etc
Self-motivated with a willingness to take ownership of tasks
A passion for shipping quality products
4+ years of industry experience or relevant projects
Solid understanding of statistics, and various tools and methodologies for evaluating uncertainty in a way that is specific to the given product being shipped

Benefits

Comp & perks

Comprehensive health and wellness benefits, including medical, dental, vision, and additional support programs.
The opportunity to work on cutting-edge AI with a small, mission-driven team
A culture that values transparency, trust, and community impact

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

programmingdeep learninglanguage modelsreward model trainingLLM fine tuningprompt engineeringfunction callingstatisticsevaluation methodsdata modeling

Soft Skills

self-motivatedownershippassion for qualityfeedback cultureteam collaborationrapid product iteration