Principal Engineer

Fluxx; United States; On-site; USD 148,000 - 210,000; Full time

Benefits offered by this job

Medical insurance

Flexible time off

12 weeks parental leave

Learning stipend

Home office stipend

401(k) with company match

Stock options

Job summary

Fluxx is seeking a Principal Engineer to drive architecture and hands-on implementation on our grantmaking platform. You will guide cross-functional teams, influence product direction, and deliver high-quality code end-to-end.

You’ll mentor engineers, advocate for robust design, performance, and maintainability, and help evolve our AI-assisted development practices. Remote within the United States, full-time exempt role.

Qualifications

• Senior-level software engineering experience with SaaS platforms.
• Proven track record leading architectural decisions and large-scale initiatives.
• Strong communication with product, design, and infrastructure teams.
• Experience mentoring engineers and raising the technical bar.

Responsibilities

• Lead architecture and implement major platform initiatives.
• Make sound architectural trade-offs and set direction.
• Provide end-to-end technical leadership across SDLC phases.
• Mentor engineers and raise team technical literacy.
• Champion AI-assisted development in workflows.

Skills

8+ years software engineering

Full-stack Rails/React

Architectural leadership

Code quality & testing

Mentorship & team leadership

AI in SDLC

Tools

Rails

Node.js

React

AWS

MySQL

Elasticsearch

Redis

Job description

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
• 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 backend depth using Ruby on Rails and the ability to engage credibly with frontend work in 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

Technical Experience:

• Large Rails codebases
• Node.js and modern JavaScript/TypeScript - we expect our Node footprint to grow and value engineers who can speak credibly across both ecosystems
• AWS and DevOps fundamentals - you do not need to be an infrastructure specialist, but you should be comfortable reasoning about deployment, scaling, and observability
• MySQL at scale, including query optimization, indexing strategies, and schema migrations on live systems
• Elasticsearch, Redis, Resque, and other supporting services in a production Rails environment
• AI‑assisted development workflows, including thoughtful use of agents, prompt design, and the operational realities of keeping agentic SDLC pipelines healthy
• B2B SaaS platforms, particularly those with highly configurable customer‑specific behavior

Bonus points if you have some experience with Go, Python and other modern languages used in systems targeting high‑performance and concurrency features, and Java

Salary:

Fluxx is committed to fair, transparent, and equitable compensation practices. We use a market based approach that considers cost of labor by geographic region, along with company size and industry benchmarks.

This role is categorized into two compensation zones based on location, with the following expected annual base salary:

• Zone 1 – San Francisco Bay Area & New York City $164,000- $210,000
• Zone 2 – All other locations $147,600- $199,800

The range listed reflects the expectations outlined in this job description. The final salary and commission package will be determined based on, but not limited to:

• the candidate's location, (b) individual skills and qualifications, and (c) relevant experience.

Benefits:

Medical, dental, and vision insurance; Flexible time off; Paid sick leave; 12 weeks of fully‑paid parental leave; Annual learning and development stipend; Internet stipend; One‑time home office set‑up stipend; 401(k) retirement plan with company match. This position is also eligible for incentive stock options, subject to the terms of Fluxx's applicable stock plans.

About Fluxx:

At Fluxx, our mission is to be the leading collaborative grant management platform in our global communities. We build technology that drives positive impact by helping foundations, government agencies, and nonprofits streamline the grantmaking process—making it easier to get funding to the organizations that need it most. For more than 15 years, we've helped organizations move away from manual processes and legacy tools to a flexible, AI + data‑driven platform that supports the full lifecycle of grantmaking. Today, Fluxx supports a global community of 400+ customers who collectively manage and distribute more than $39B in grants annually.

We are a people‑first and inclusive workplace committed to continuous learning. We pride ourselves on having a diverse workforce and we do not discriminate against any employee or applicant because of race, creed, color, religion, gender, sexual orientation, gender identity/expression, national origin, disability, age, genetic information, veteran status, marital status, pregnancy or related condition, or any other basis protected by law. We respect the gender, gender identity and gender expression of our applicants and employees. It is our policy to comply with all applicable national, state and local laws pertaining to nondiscrimination and equal opportunity.