Product Engineer

Blacksmith; New York (NY); On-site; USD 200,000 - 300,000; Full time

Benefits offered by this job

401K match

Equity

Unlimited PTO

Annual offsite

Early-exercise stock options

Parental leave

Job summary

Blacksmith is hiring in NYC for a frontend-focused software role. You will work on Codesmith, our background coding agent, designing workflows, UI, and the infrastructure that enables engineers to delegate coding tasks to AI and ship faster.

You will build tools to debug flaky CI jobs, surfacing patterns and logs to aid root-cause analysis. The role emphasizes strong CS fundamentals, React expertise, and collaboration with design for high-performance UIs.

Qualifications

• Strong CS fundamentals and deep understanding of React and modern frontend development.
• 3+ years of software development experience.
• Willingness to work in person in NYC 5 days a week.

Responsibilities

• Build and evolve the Codesmith background coding agent and UI workflows.
• Create tools to debug flaky CI jobs and surface root causes.
• Collaborate with design to deliver high-performance analytics and observability surfaces.
• Prototype AI-powered features from prompts to backend and UI.
• Contribute to agent platform architecture and sandboxed workspace orchestration.

Skills

CS fundamentals

React

Frontend development

Job description

About Blacksmith

• We started by building infrastructure to run CI workloads really fast. Our first product helps companies run GitHub Actions substantially faster and cheaper by owning and operating our own global fleet of bare-metal machines rather than renting generic cloud VMs.

• Today, we orchestrate tens of millions of Firecracker VMs each month, running CI for 2,000+ companies and hit ~$10M in ARR in less than 2 years.

• We operate thousands of bare-metal machines across multiple regions, regularly schedule 50k+ vCPUs concurrently, and run a petabyte-scale Ceph cluster that we manage ourselves.

• We’ve raised $13.5M across Seed and Series A, led by Google Ventures (GV), and we’re intentionally building a small, but exceptional team.

• Blacksmith was founded by a team with deep systems and scaling experience, including building search/ads infrastructure at Faire, and operating large distributed systems at Cockroach Labs. Our GTM is led by Jon Boyer, formerly Head of Sales at Zapier.

• We’re now extending the same CI infrastructure into a broader platform: running agent sandboxes at scale and building our own background coding agent on top of it.

What you could work on

• Build and evolve Codesmith, our background coding agent — designing the workflows, UI, and infrastructure that let engineers delegate coding tasks to AI and ship faster

• Create tools that help engineers and AI agents debug flaky CI jobs: surfacing patterns in test failures, correlating logs with infrastructure signals, and making root cause analysis fast and intuitive

• Work closely with design to ship polished, high-performance product surfaces across our analytics and observability platform, where engineers go to understand their CI systems

• Prototype and iterate rapidly on AI-powered features — from natural language interfaces to automated fix generation — and own the full stack from prompt design to backend service to UI

• Contribute to the architecture of the agent platform: 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 3+ 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 start-up projects.

• You’re comfortable creating new processes and iterating on them quickly.

Compensation and 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)

Compensation

$200K - $300K Offers Equity