Senior Product Engineer
Blacksmith · New York City
About this role
**About Blacksmith** Blacksmith builds infrastructure to run CI workloads really fast. Our product helps companies run GitHub Actions substantially faster and cheaper by owning and operating our own global fleet of bare-metal machines (instead of renting generic cloud VMs). We orchestrate tens of millions of Firecracker VMs each week, run CI for 7,000+ companies, and manage a petabyte-scale Ceph cluster across multiple regions. We’ve grown 10x so far in 2026 and raised $58.5M (Seed to Series B) led by Google Ventures (GV) & Peak XV Partners. **What you could work on** - Build and evolve **Codesmith**, our background coding agent—designing workflows, UI, and infrastructure so engineers can delegate coding tasks to AI and ship faster. - Create tools to help engineers and AI agents **debug flaky CI jobs**: surface patterns in test failures, correlate logs with infrastructure signals, and make root-cause analysis fast and intuitive. - Partner closely with design to ship **polished, high-performance product surfaces** across our analytics and observability platform. - Prototype and iterate rapidly on **AI-powered features** (natural language interfaces, automated fix generation) and own the full stack—from prompt design to backend services to UI. - Contribute to the **agent platform architecture**: how we run sandboxed workspaces and orchestrate agent sessions. **You are a good fit if you** - Have strong CS fundamentals and a deep understanding of **React** and modern frontend development. - Can work closely with design to build polished, high-performance UIs—and aren’t afraid to go deep on browser performance, rendering bottlenecks, or complex component architecture. - Have **5+ years** of software development experience. - Enjoy working **in person 5 days a week in NYC**. - Enjoy working at a very early-stage startup and are comfortable with ambiguity. **Bonus** - You’ve dabbled in your own side hustles or startup projects. - You’re comfortable creating new processes and iterating on them quickly. **Compensation & Benefits** - Medical, Vision, and Dental insurance - Competitive base + equity - 401K match - Unlimited PTO - Annual offsite - Early-exercise stock options - 12 weeks fully paid parental leave (US)
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