Senior Software Engineer (RLE)
About Handshake
Handshake is the career network for the AI economy. 20 million knowledge workers, 1,600 educational institutions, 1 million employers (including 100% of the Fortune 50), and every foundational AI lab trust Handshake to power career discovery, hiring, and upskilling, from freelance AI training gigs to first internships to full-time careers and beyond. This unique value is leading to unparalleled growth; in 2025, we tripled our ARR at scale.
Why join Handshake now:
Shape how every career evolves in the AI economy, at global scale, with impact your friends, family and peers can see and feel
Work hand-in-hand with world-class AI labs, Fortune 500 partners and the world’s top educational institutions
Join a team with leadership from Scale AI, Meta, xAI, Notion, Coinbase, and Palantir, among others
Build a massive, fast-growing business with billions in revenue
About the Role
We’re hiring a Senior Software Engineer to build our Reinforcement Learning Environments (RLE) platform—the interactive systems where frontier AI models learn to complete real-world work.
RLE environments simulate workflows (e.g., software engineering, finance, legal) with realistic tools, constraints, and feedback loops. The data generated powers training and evaluation for model quality, robustness, and task completion.
This is a high-ownership role with direct impact on how models learn and how quickly new domains scale.
Location: San Francisco, CA (in-office, 5 days/week)
What You’ll Do
Build and scale our reinforcement learning environments and the platforms behind them
Drive architecture for scalable, reliable, extensible environment systems and data generation pipelines
Partner with Research, Product, and Ops to turn ambiguous needs into production systems
Build modular, plug-and-play domains that integrate cleanly with training and evaluation loops
Raise the bar on reliability, observability, performance, and data quality
What We’re Looking For
6+ years building backend, distributed systems, or ML infrastructure
Proficiency with ReactJS and TypeScript, with deep knowledge of backend architectures.
Strong command of relational databases (e.g., PostgreSQL), data modeling, system design, and distributed systems principles.
Experience with cloud infrastructure (AWS, GCP), CI/CD pipelines, and operating production systems at scale.
Nice to Have
Experience with RL training infrastructure, simulation systems, or evaluation platforms
Working in an operations-heavy, tech-enabled environment
Experience supporting applied ML or AI research teams
What Success Looks Like
RLE becomes a trusted platform for training workflow-capable models
New domains launch quickly with high-quality data
Systems are reliable, scalable, and drive measurable model improvements
Perks
Handshake delivers benefits that help you feel supported—and thrive at work and in life.
The below benefits are for full-time US employees.
🎯 Ownership: Equity in a fast-growing company
💰 Financial Wellness: 401(k) match, competitive compensation, financial coaching
🍼 Family Support: Paid parental leave, fertility benefits, parental coaching
💝 Wellbeing: Medical, dental, and vision, mental health support, $500 wellness stipend
📚 Growth: $2,000 learning stipend, ongoing development
💻 Office: Commuting support, free lunch, and gym in our SF office
🏝 Time Off: Flexible PTO, 15 holidays + 2 flex days
🤝 Connection: Team outings & referral bonuses
