Senior Systems Engineer

Blacksmith; New York (NY); On-site; USD 140,000 - 200,000; Full time

Job summary

Blacksmith is building a fast, self-hosted CI infrastructure and a scalable worker platform in NYC. We’re seeking engineers with 5+ years in software development and deep experience with distributed systems and performance tuning.

You’ll work closely on low-level systems in C, C++, Go, Rust, or Zig and join a small in-person team five days a week to ship core infrastructure. Ideal candidates thrive on building from first principles, enjoy operating large-scale bare-metal fleets, and are excited

Qualifications

• 5+ years of software development experience, preferably in distributed or performance-critical environments.
• Comfort writing and debugging in C, C++, Go, Rust, or Zig and focus on correctness and safety.
• Familiarity with self-hosting infrastructure and build/configuration tooling.
• Willingness to work in person in NYC five days a week.

Skills

Distributed systems

C

C++

Go

Rust

Zig

Performance optimization

Self-hosting

Tools

Ansible

Puppet

Chef

Ceph

MinIO

Job description

• 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 3,000+ companies and hit ~$10M in ARR in less than 2 years. We’ve already more than 5X'd revenue since the start of 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 Capital, 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.

You are a good fit if you

• Have developed and scaled distributed systems and enjoy digging into performance and reliability issues across the filesystem, network, and storage stack.
• Are comfortable writing and debugging in C, C++, Go, Rust, or Zig, and care deeply about efficiency, correctness, and safety at the systems level.
• Are excited by the idea of self-hosting and managing infrastructure with build automation and configuration management tools (e.g., Ansible, Puppet, Chef).
• Have familiarity with distributed storage systems like Ceph or MinIO, or are eager to get hands-on with them.
• Have 5+ years of software development experience, ideally in performance-critical or distributed environments.
• Enjoy working in person 5 days a week in NYC with a small, tight-knit team.
• Thrive in the ambiguity of an early-stage startup and are energized by building from first principles.

Bonus

• You’ve dabbled in your own side hustles or start-up projects.
• You’re comfortable creating new processes and iterating on them quickly.