The Principal Full Stack Software Engineer will lead technical initiatives, architect solutions across the stack, and mentor engineers. Responsibilities include managing user systems, core applications, and optimization of design processes.
Principal Full Stack Software Engineer
About JITX
JITX is revolutionizing circuit board design by making it code-first. Instead of dragging components around in a GUI, engineers write code—or have AI write it for them—to define their circuit boards. We're a ~20-person startup building tools that bring software engineering practices to hardware design.
The Role
We're looking for a principal engineer who can drive technical direction for significant product areas and own them end-to-end. You'll work across our stack—from user management systems to our core design application—making architectural decisions that shape how electrical engineers interact with our product for years to come.
As a principal engineer, you'll be expected to identify technical debt, propose solutions, and drive consensus around the right path forward. Your first major project will be reworking our user and license management system, which you'll architect and largely implement while coordinating with stakeholders across the company. As you ramp up and build context on our domain, you'll transition to working on critical core runtime components that power our circuit design engine.
Beyond your individual contributions, you'll raise the bar for engineering across the team—through code reviews, technical mentorship, and establishing patterns that others can follow.
What You'll Work On
User Management Platform
- TypeScript/React frontend
- Python application server
- Database backend currently in PostgreSQL
- Integration with modern auth solutions (WorkOS or similar)
Graphical User Interface Application
- Electron based React/TypeScript application
- Custom input handling and rendering (not traditional HTML elements)
- Advanced visualization using PixiJS, with potential migration to WebGL/Three.js
- Complex CSS/styling for polished UI/UX
Application Runtime & Architecture
- Algorithm-heavy runtime with complex computational geometry problems
- User-facing Python API for programmatic circuit board design
- Sophisticated architecture driving the application life cycle
- Opportunity to rearchitect core systems to leverage parallel computing and modern hardware capabilities
- Deep technical challenges requiring strong CS fundamentals and architectural vision
What We're Looking For
Must-haves:
- Extensive full stack experience with TypeScript/React and Python, with a track record of architectural decisions at scale
- Strong algorithmic problem-solving skills with understanding of complexity analysis, graph/tree data structures, and computational efficiency
- Ability to drive technical direction and follow through on architectural decisions across the stack
- Experience identifying technical debt, evaluating tradeoffs, and building consensus around solutions
- Self-directed work style with strong product sense and ability to unblock yourself and others
- Experience gathering requirements from stakeholders and translating them into technical solutions and system designs
- Track record of owning large, complex features from planning through production
- Ability to mentor and raise technical standards across a team through code reviews and establishing best practices
- Comfortable working with ambiguity in a startup environment
Nice-to-haves:
- Experience with graphics/visualization libraries (PixiJS, Three.js, WebGL)
- Background in developer tools or technical products
- MongoDB and PostgreSQL experience, or other databases
- Auth/identity management systems (WorkOS, Auth0, etc.)
- Polyglot programming experience—comfortable across multiple languages and paradigms
- Interest in hardware, electronics, or CAD tools
Who You Are
You're a veteran software engineer who's worked across multiple environments and knows that early-stage startups offer the best combination of impact and interesting problems to solve.
You have a nose for bottlenecks—you spot where things are getting stuck and jump in to help get features across the finish line. You're naturally curious about architecture, always tinkering to find proactive improvements that can ship quickly. You move fluidly across the codebase and the team, bringing speed without sacrificing quality.
Your algorithmic problem-solving is strong and you don't shy away from maths and logic. You're comfortable reasoning about complexity at various levels of abstraction, working with graph and tree structures, and finding elegant solutions to hard computational problems.
You're responsible with your craft. You plan, you test, you own large features end-to-end. You think about staging, reliability, and production-readiness from the start, not as an afterthought.
At a principal level, you're also a multiplier. You make the engineers around you better through thoughtful code reviews, clear technical communication, and by establishing patterns that scale beyond your own code. You know when to dive deep into implementation and when to step back and focus on architecture and direction.
You thrive when given ownership of a problem space. You're the person who asks "why are we building this?" before diving into "how should we build it?" You don't need your hand held, but you're not afraid to raise your hand when you need context or when you spot a problem with the plan.
Why JITX?
- Work on genuinely novel problems at the intersection of software and hardware
- Small team where your work has immediate, visible impact
- Help shape the future of how hardware gets designed
- Collaborate with a team that cares deeply about craft and elegant solutions
Top Skills
Auth0
Electron
MongoDB
Pixijs
Postgres
Python
React
Three.Js
Typescript
Webgl
Workos
JITX Berkeley, California, USA Office
1207 10th St, Berkeley, CA, United States, 94710
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