Senior Fullstack Engineer

As a Senior Fullstack Developer, you will be a key contributor to our core product, building and scaling features that are central to the donation experience for millions of users. You’ll leverage your expertise in Node.js, React, and TypeScript to develop complex components-from dynamic donation widgets to data-driven admin dashboards-with a relentless focus on code quality, scalability, and user experience.

This is an ideal opportunity if you love solving real-world problems at scale and want to grow within a mission-driven, high-impact engineering culture.

What You’ll Do

• Design, build, and maintain resilient frontend and backend features using React and Node.js.
• Develop our core products, including donation checkouts, embeddable widgets, and donor/partner portals.
• Architect and develop system components that scale across millions of monthly transactions.
• Write clean, well-documented, and thoroughly testable code.
• Drive architecture and technical design discussions to find elegant solutions to complex problems.
• Mentor peers by conducting thoughtful code reviews and providing constructive feedback.
• Partner with product managers and designers to clarify requirements and shape the roadmap.
• Proactively identify and resolve bugs, performance bottlenecks, and optimization opportunities.
• At Fundraise Up, AI is a default tool, not an experimental one. We expect every team member to actively use AI in their day-to-day work, identify where AI can change the shape of problems in their function, and grow their fluency as the tools evolve. You should already be using AI meaningfully in your work and understand where it adds value and how it can improve the way you operate., * Home Office Setup Assistance: the company offers assistance with purchasing furniture (office chair, office desk, monitor) and other items to create a comfortable workspace.
• English learning courses.
• Relevant professional education.
• Gym or swimming pool.
• Co-working.
• Remote working.
• Please note: All official correspondence from Fundraise Up will exclusively originate from the @fundraiseup.com domain. Exercise caution and ensure the authenticity of emails claiming to be from our company.

We are an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. We do not discriminate on the basis of race, color, religion, gender, sexual orientation, gender identity or expression, age, national origin, disability, or any other characteristic protected by applicable law in the countries where we operate.

• 7+ years of professional fullstack development experience.
• Deep understanding of modern JavaScript (event loop, closures, promises, prototypes).
• Expert-level proficiency with React and its ecosystem (familiarity with Vue is a plus).
• Strong backend expertise with Node.js (experience with Koa or NestJS is highly preferred).
• Experience with Webpack configuration, performance optimization, and profiling.
• A keen eye for detail and a high sense of ownership and accountability for your work.

Nice to Have

• Experience with MongoDB, ClickHouse, or Elasticsearch.
• Familiarity with Docker, CI/CD pipelines, or cloud infrastructure.
• Contributions to open-source projects or a strong personal portfolio.

Bonus points

• Curiosity and a hypothesis-driven mindset.
• Ability to communicate complex analytical concepts to non-technical audiences.
• Detail-oriented with a strong sense of ownership.
• Comfort working in fast-paced, data-rich environments.

• A strong, collaborative product team that owns what it builds.
• Clear product vision and access to real customer feedback from global nonprofit leaders.
• Flat structure: no politics, just great work with great people.
• Transparent company culture-we share how we’re growing, where revenue comes from, and what’s next.
• Long-term focus: we offer equity options and value sustained, meaningful contribution.

Compensation

• The compensation range for this role is: €5,000 - €6,400 gross per month.
• Final compensation will be determined based on relevant experience, skills, qualifications, and alignment with the role’s requirements.

About Fundraise Up

We’re Fundraise Up - a global fundraising platform built to make donating to nonprofits fast, seamless, and accessible to all. Every month, our technology powers tens of millions of dollars in donations across the globe. We focus on innovation that directly impacts results: faster load times, higher conversion rates, global payment support, and accessibility-first design.

Our platform is trusted by many of the world’s leading nonprofits, including UNICEF, the Alzheimer’s Association, and a wide range of global NGOs. With a 4.9/5 rating across top software review platforms, we’re recognized not just for our impact - but for the quality of the product we deliver.

A Truly Global Product

We operate in the enterprise segment, serving nonprofit organizations across North America, the United Kingdom, Australia, and Europe.

We’re building a large and complex product ecosystem that serves nonprofits, donors, and partners around the world. The platform includes a modern checkout experience and customizable widgets (each a standalone SPA), donor, organization, and partner portals, admin tools, and several internal apps.

Our backend is powered by Node.js (Koa, NestJS) and MongoDB. The frontend stack includes Webpack, Vue.js, and React, with nearly all code written in TypeScript. For high-throughput messaging and background processing, we use Kafka (for millions of events) and Bull (Redis). Analytics data is stored in ClickHouse, and we use Elasticsearch for search.

The Team

We are a distributed team of 160+ product professionals, including 80+ engineers. Our team members are mainly based across Spain, Poland, Portugal, Georgia, Armenia, Serbia, Turkey, and Cyprus. Many of our developers bring 5 - 10+ years of experience, and we foster a culture of deep technical curiosity and knowledge sharing.

Despite our scale, we operate like a focused team - where every task matters and every voice is heard. We value thoughtful collaboration, strong engineering practices, and a product mindset. You’ll be joining a team where quality, mentorship, and mutual respect come first.