Senior Fullstack Engineer Fluxx is looking for a highly motivated Senior Fullstack Engineer to join the Grantseeker Engineering team . As a Senior Fullstack Engineer, you will play a key role in designing, building, and scaling the Grantseeker Pro platform, along with other customer-facing and internal products. You’ll work closely with product, design, and engineering leadership to deliver high-quality, performant software that directly impacts nonprofits and grantmakers worldwide.

Reporting to the VP of Engineering (Ben Holzman), you will help shape technical direction, contribute to architectural decisions, and mentor other engineers on the team. This role requires strong ownership, a product mindset, and the ability to move quickly while maintaining high engineering standards. We are looking for people who are curious, tenacious, intellectually honest, and have a bias toward action.

We welcome diverse perspectives and encourage you to apply if you think you can bring value to our team—even if your experience doesn’t perfectly match the job description. This is a full-time exempt position based out of New York City. Candidates must be located in New York and willing to work from the office at least 4 days a week.

About Fluxx: At Fluxx our mission is to be the leading collaborative grantmaking platform in our global communities. We believe in building technology that drives positive impact in our world. Our platform helps foundations and agencies streamline the grantmaking process, making it easier to get funding to those that need it to support their mission.

We are driven to help facilitate change through our solutions that automate grantmaking for organizations all over the world. Over the past decade, Fluxx has built a diverse and engaged community of 350+ grantmakers who work with over 150,000 foundations, government agencies and nonprofits worldwide. Through Fluxx, they have issued over $15B in grants in the past year alone.

What You Will Do

: Design, build, and maintain fullstack features across the Grantseeker Pro platform and related products Collaborate cross-functionally with product managers, designers, and engineers to deliver high-impact user experiences Contribute to system architecture and technical decision-making, ensuring scalability, performance, and reliability Write clean, maintainable, and well-tested code across frontend and backend systems Lead and participate in code reviews, providing thoughtful feedback and mentoring other engineers Improve development processes, tooling, and engineering standards to increase team velocity and product quality What you bring to the team/ About you: 10+ years of professional software engineering experience, with strong fullstack development expertise Proficiency in React/TypeScript/JavaScript , with experience building modern web applications (frontend and backend) Experience working with PostgreSQL and designing efficient data models Familiarity with cloud infrastructure, preferably Google Cloud Platform (GCP) Experience with or interest in Claude Code (Anthropic) or AI-assisted development tools Strong problem-solving skills, ownership mindset, and ability to work effectively in a remote, collaborative environment 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.

tiers based on location, with the following expected annual on-target earnings (base salary + commission): Zone 1 – New York City $171,000- $231,000 The range listed reflects the expectations outlined in this job description.

Qualifications

, and (c) relevant experience.

Benefits

: Fluxx offers the following

for the