Senior Backend Engineer en Remote, Spain, España

As a Backend Engineer, you will be a key architect of the engine that powers our global platform. You'll resolve complex challenges in a high-load, distributed system, building and scaling the infrastructure that processes millions in donations. This is not a maintenance role; it's a high-impact, product-focused engineering position where clean architecture, performance, and reliability are paramount.

You will work on a complex product ecosystem-from our modern checkout experience to donor portals and massive analytics pipelines-all powered by a cutting-edge tech stack.

• Backend: https://jobeax.com/link/JSd7UYCSg572jJDY (Koa, NestJS), TypeScript
• Database: MongoDB
• Infrastructure: Kafka for event streaming, Bull (Redis) for background jobs, ClickHouse for analytics, and Elasticsearch for search.

• Design, build, and maintain clean, efficient, and scalable backend services in https://jobeax.com/link/JSd7UYCSg572jJDY and TypeScript.
• Develop new product features from concept to deployment, collaborating closely with product managers and frontend engineers.
• Own key parts of our backend architecture, making critical decisions that enhance performance, reliability, and security.
• Write comprehensive unit tests and conduct thorough code reviews to maintain code quality.
• Proactively identify and implement system improvements, refactoring legacy code where necessary.
• Contribute to a culture of engineering excellence by mentoring others and sharing your expertise.
• 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.

• Prior experience working in a remote-first, globally distributed team.
• Experience with performance monitoring and observability tools (e.g., Prometheus, Grafana, Datadog).
• A genuine interest in the non-profit technology sector.
• A hypothesis-driven mindset and the ability to communicate complex technical concepts to non-technical stakeholders.
• 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

• The compensation range for this role is: €5,600 - €6,500 gross per month.
• Final compensation will be determined based on relevant experience, skills, qualifications, and alignment with the role's requirements.
• Private medical insurance for the employee and their family.
• 23 paid vacation days per year.
• 11 paid public holidays per year.
• 5 company-paid sick leave days.
• English learning courses.
• Relevant professional education.
• Gym or swimming pool.
• Home Office Setup Assistance: the company offers assistance with purchasing furniture (office chair, office desk, monitor) and other items to create a comfortable workspace.
• Co-working.
• Remote working.

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.

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 https://jobeax.com/link/JSd7UYCSg572jJDY (Koa, NestJS) and MongoDB. The frontend stack includes Webpack, https://jobeax.com/link/tzGekrj9a8ToGEDv, 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.

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.

Location: Remote (CET hours preferred)

Language: Russian-speaking team

• Experience: 7+ years of backend development experience, preferably in a product-driven environment.
• https://jobeax.com/link/JSd7UYCSg572jJDY Expertise: Strong, hands-on experience with https://jobeax.com/link/JSd7UYCSg572jJDY and modern frameworks like Koa or NestJS.
• TypeScript Pro: Deep expertise in TypeScript, including its advanced typing and module systems.
• Database Skills: Solid experience with MongoDB or other NoSQL databases.
• Distributed Systems: Familiarity with event-driven architecture using tools like Kafka, RabbitMQ, or Bull/Redis.
• Data & Search: Hands-on experience with ClickHouse (or similar analytics DBs) and Elasticsearch.
• Architectural Mindset: A strong understanding of system design, clean architecture principles, and performance optimization.
• Ownership: The ability to work independently, take ownership of your work, and see projects through to completion.
• Communication: Comfortable working within a Russian-speaking team.

• 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.

**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.