All positions

Founding Engineer

San Francisco, CA or Los Angeles, CAFull-timeOn-site$200K – $250K + Equity

Pay range is a good-faith estimate for this role and may vary based on experience and leveling.

Job Description

Founding Engineer

About the Role

We’re hiring a Founding Engineer to help architect and scale the core platform at Proaction. This is a hands-on, high-ownership role for someone who operates at a staff level but is excited to build in a fast-moving, early-stage environment.

You’ll work directly with the CTO to define system architecture, establish engineering standards, and build the foundation that the company scales on. This role is for someone who wants to shape both the product and the engineering culture from day one—and grow into a long-term technical leader.

Our stack includes a modern TypeScript backend (NestJS), PostgreSQL, and AWS infrastructure, with a React frontend.

What You’ll Do

  • Own backend architecture and system design for a multi-tenant, enterprise SaaS platform
  • Design and build durable, scalable workflows and core infrastructure systems
  • Lead technical decision-making with a pragmatic, long-term lens
  • Establish engineering standards across code quality, testing, deployment, and security
  • Ship complex, cross-cutting features end-to-end
  • Partner closely with the CTO and product team to translate business needs into technical systems
  • Help shape the engineering culture: high ownership, low ego, strong collaboration
  • Be deeply hands-on: this is a building role, not a management role

What We’re Looking For

  • 5+ years of experience building and scaling production software systems
  • Proven ability to operate at a senior/staff level in system design and architecture
  • Strong backend fundamentals (data modeling, APIs, distributed systems, performance)
  • Experience building or scaling enterprise SaaS platforms
  • Comfort working in ambiguity and bringing structure to messy systems
  • High ownership mindset: you take responsibility for outcomes, not just code
  • Low ego, high standards: you care about the best idea, not being right
  • Strong communication skills and the ability to influence technical direction

AI at Proaction

We are an AI-native engineering team.

You should be highly comfortable using AI as a core part of how you build: writing, debugging, and reasoning about code with tools like Cursor or Claude Code. We expect engineers to push beyond basic autocomplete and use AI to accelerate system design, implementation, and iteration.

If you still primarily write code without AI, this is not the right role.

Why Proaction

We’re building software for a massive, underserved industry and replacing legacy systems with something modern and scalable.

As a founding engineer, you’ll have:

  • Direct ownership over core systems and architecture
  • A seat at the table for key technical and product decisions
  • Equity in a company being built for long-term impact
  • The opportunity to grow into a senior technical leadership role as the team scales

If you want to build foundational systems, operate with high ownership, and shape the trajectory of a company from the earliest days, we’d love to talk.