Staff Frontend Engineer – WebAssembly & Bundling ($100K – $300K + Equity) at well-funded AI design startup

Jack & Jill/External ATS • San Francisco, CA

5h • $100,000 - $300,000

About The Position

You will architect a browser-native execution environment that delivers instant development experiences by running dependencies and tooling entirely inside the browser. This runtime and systems engineering role involves building a high-performance virtual filesystem and secure sandboxing. You will set the technical direction for platform infrastructure to reinvent how product teams work.

Requirements

• Has 8-12+ years of experience building systems software with a deep focus on WebAssembly memory models and host interfaces.
• Possesses expert-level knowledge of browser platform internals including Workers, messaging, and event loop scheduling.
• Demonstrates a proven track record of architecting production-grade platform infrastructure at a high-growth technology company.

Responsibilities

• Architect a Node-like browser runtime including task orchestration, streaming I/O, and a high-performance virtual filesystem.
• Integrate and optimize JavaScript/TypeScript tooling pipelines to drive measurable improvements in cold start and memory performance.
• Design and implement secure sandboxing environments for running untrusted code with strong isolation under real browser constraints.

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed