Senior Product Engineer

Blacksmith blacksmith.sh Open · verified Oct 24, 2026

On-site New York Full-time Senior Software Engineering

At a glance

Senior Software Engineering role at Blacksmith. New York · full-time · $200,000–$300,000 base.

SalaryStated by Blacksmith

$200,000 – $300,000

Base salary for this role, in USD per year, as published in the posting.

This role, from BlacksmithOur estimate for the market: $175,500–$232,323Median $200,000

The range includes the market median of $200,000 for senior software engineering roles in New York.

Worked out from 227 postings that stated pay, median $200,000. Last updated Oct 23, 2026.

RoleSoftware Engineering

SenioritySenior

LocationNew York

WorkplaceOn-site

EmploymentFull-time

Base pay$200,000–$300,000

PostedApr 30, 2025 · 1y ago

Role brief

techroles summary, based on the employer's posting.

What you'll do

Build Codesmith’s coding-task workflows, interface and underlying systems so engineers can hand work to an AI agent
Help engineers find recurring test failures by connecting log evidence with infrastructure signals and guiding root-cause checks
Work with design on fast, polished analytics and observability screens for understanding CI systems
Prototype AI features such as natural-language controls and automatic fixes, handling prompts, backend services and UI
Shape how sandboxed workspaces run and how the platform coordinates agent sessions

What you bring

At least five years of software development experience
Strong computer science fundamentals and deep knowledge of React and current frontend development
You can build polished, responsive interfaces with design partners and investigate browser speed, rendering and component-structure problems

Who this fits

This role suits a senior engineer who wants to work across frontend, backend and AI product development, and is comfortable with early-stage ambiguity. You’ll work in person in New York City five days a week.

From the employer

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 week, running CI for 7,000+ companies and tens of millions in ARR. We’ve grown 10x so far in 2026.
We operate thousands of bare-metal machines across multiple regions, regularly schedule 100k+ vCPUs concurrently, and run a petabyte-scale Ceph cluster that we manage ourselves.
We’ve raised $58.5M from Seed to Series B, led by Google Ventures (GV) & Peak XV Partners, 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 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