Senior Fullstack Engineer

SquarePeg; New York (NY); On-site; USD 171,000 - 231,000; Full time

Benefits offered by this job

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

401(k) retirement plan with company match

Incentive stock options

Job summary

Fluxx is seeking a highly motivated Senior Fullstack Engineer to join the Grantseeker Engineering team. You will design, build, and scale the Grantseeker Pro platform, collaborating with product and engineering leadership to deliver compelling software that benefits nonprofits and grantmakers worldwide.

This is a full-time role based in New York City, requiring in-office work at least 3 days a week. Ideal candidates will have 10+ years of engineering experience, strong ownership, and a product mindset.

Benefits include competitive salary, medical insurance, flexible time off, and more. Salary ranges from $171,000 to $231,000 based on qualifications.

Qualifications

• 10+ years of professional software engineering experience.
• Strong fullstack development expertise.
• Experience with PostgreSQL and designing efficient data models.

Responsibilities

• Design, build, and maintain fullstack features across the Grantseeker Pro platform.
• Collaborate with product managers, designers, and engineers.
• Contribute to system architecture and technical decision-making.

Skills

Fullstack development expertise

PostgreSQL

Google Cloud Platform (GCP)

AI-assisted development tools

Strong problem-solving skills

Ownership mindset

Job description

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 3 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.

How you will make an impact/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
• 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

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 three compensation 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. 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.

Fluxx offers the following benefits for the position subject to applicable eligibility requirements: 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.

More Abou Fluxx:

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.