Staff Software Engineer

About Zeffy Zeffy is the fastest-growing nonprofit platform in North America, helping organizations raise funds, run events, and engage donors. We are already working with more than 80,000 nonprofits and are doubling annually. Millions of people dedicate their lives to causes beyond profit, running schools, shelters, and community initiatives. Yet most still lack modern tools. We believe the greatest opportunity for technology today is to amplify the impact of nonprofits. Built on a sustainable, self-funded model, Zeffy reaches over 1M donors monthly and grows profitably, giving us the freedom to focus fully on our mission. Nonprofit workers are heroes. They deserve the best technology, and we’re hiring top minds and top hearts to build it for them. About the role As a Staff Software Engineer at Zeffy, you’ll work on key product features while playing a central role in elevating the engineering team. You’ll bring experience that helps others make better technical decisions, navigate complexity with confidence, and maintain our focus on building simple, high-quality solutions as we grow. Development Principles at Zeffy We always optimize the ratio impact / effort, it’s what we call Zeffy perfectionism, perfection in impact. We build the simplest solution first to validate ideas quickly, keeping the codebase clean without solving problems that don’t exist yet. We are organized in 2 months cycle, to make sure we prioritize radically. We set ourselves targets on the 4 following dimensions: efficiency, security, stability and performance. Trust and ownership: every target is clear and owned by one person who has full autonomy to reach it. Owned by one person doesn’t mean working alone on it. Continuous improvement: We regularly review and refine our processes, promoting a culture of learning and growth through feedback. Read more: https://zeffy.notion.site/Zeffy-Engineering-Blog-3505553ff3658091becedbbd71f70ece Our Stack Frontend: React/Next.js (Typescript) Backend: Nest.js (TypeScript) Database: PostgreSQL, Algolia CI/CD: GitHub Actions, Cypress Preferred experience (qualifications) We’re looking for someone with at least 8 years of experience as a developer in SaaS or web-based products that serve high-volume and rapidly growing user bases. We move fast by keeping things simple, and we want someone who embodies that mindset: someone who knows when structure adds value, when it gets in the way, and how to guide others toward the right balance. You’ve shipped complex products at scale, learned from real-world successes and failures, and developed sharp judgment about what truly matters. You bring seniority through expertise and perspective rather than hierarchy, making clear, pragmatic decisions that balance speed, quality, and long-term thinking. You value clarity over cleverness, simplicity over complexity, and momentum over perfection. You mentor others with empathy, share your experience generously, and elevate the work of the whole team without adding unnecessary process. 💡 Research shows that candidates from underrepresented backgrounds often don't apply for roles if they don't check every box. If this applies to you and you are interested in the position, we'd love to hear from you! What’s in it for you 🏖️ 5 weeks holiday + RTT per calendar year 💰 Competitive stock option program 🏥 Health insurance (with Alan) 🚲 Allowance for ecological transport #bike #transit 🤝 Team volunteering four times per year 🏢 Offices located in the heart of Paris 11ème, with the possibility of flexible, hybrid work 🌍 Offsite summit once a year with the entire team ✨ Work with individuals driven to make a profound and positive impact on the world! Recruitment Process Call with Recruiter (45 min) Meeting with Hiring Manager (1.5h) Case Study (2h) Cultural interview with leadership (1h) Team lunch & Reference check Job offer