Principal Engineer

Fluxx is looking for a highly motivated Principal Engineer to join the Engineering team . As a Principal Engineer at Fluxx, you'll be a senior technical leader on our engineering team, responsible for driving the architecture and implementation of large, cross-cutting initiatives on our grantmaking platform. You will work closely with our SVP of Engineering, our co-founding CTO, Director of Engineering, fellow Principal Engineers, and our product and infrastructure teams to make the right architectural calls, write meaningful code, and help the broader team raise its technical bar. This is a hands-on role. You'll spend the majority of your time in code, working through real problems and deliverables end-to-end, and the rest of your time on design, technical direction, and unblocking others. We are looking for someone who considers alternatives carefully, weighs trade-offs against the realities of our system, and is comfortable putting their opinions on the table and being challenged on them. This is a full-time exempt and remote position. Candidates must be located in the United States. We aren't accepting contractors. How you will make an impact: • Lead the architecture and implementation of major initiatives in our platform • Make architectural decisions counterfactually - considering several plausible approaches, surfacing the trade-offs, and choosing the best path rather than defaulting to a generic template • Provide technical leadership across all phases of large-scale engineering work, from scoping and design through implementation, code review, rollout and maintenance • Work cross-functionally with the Director of Engineering, fellow principal engineers, infrastructure engineers, product managers, DevOps, and QA to drive complex decisions on product direction and process improvements • Design and implement user-facing and backend features across the entire platform • Produce high-quality code that is well designed, thoroughly tested, and passes peer review • Lead and drive best practices with the team across the entire SDLC • Mentor engineers across the team, raise the architectural literacy of the group, and actively contribute to brainstorming and design discussions • Represent the engineering organization in leadership discussions and occasionally in direct conversations with customers. • Champion thoughtful use of AI and agents in our SDLC, helping the team amplify their work What you bring to the team: • 8+ years of professional software engineering experience, with a meaningful share of that as a principal engineer or architect on a complex SaaS platform • Deep experience as a full-stack engineer, with substantial depth using NodeJS and React • A habit of considering alternatives, naming the trade-offs, and choosing the right path for the system in front of you rather than reaching for a textbook answer • Confidence to put your opinion on the table, ask the questions others aren't asking, and engage in brainstorming and architectural debate • Strong written and verbal communication, with experience working closely with product, design, QA, and infrastructure peers • A deep foundation in computer science and a track record of making web applications highly performant • Dedication to writing and maintaining documentation that helps others move faster • Willingness to adapt to a fast-paced environment, to a codebase with a long history, and to a rapidly evolving AI-assisted development model • A track record of mentorship and of raising the technical bar of the engineers around you • Proven ability to navigate complex technical trade-offs, ensuring rapid feature delivery without compromising long-term platform scalability Technical Experience: Node.js , React and modern JavaScript/TypeScript