Backend engineer for online bookings

SumUp; Warszawa; Hybrid; PLN 180,000 - 320,000; Full time

Benefits offered by this job

Hybrid Warsaw office

Stock options

L&D budget €2000

Health insurance

Life insurance

Gym access

26 days paid leave

Sabbatical after 3 years

Referral bonus

Job summary

SumUp is seeking a senior backend engineer to design, build, and maintain scalable systems powering our Bookings product in a hybrid Warsaw office.

Join a collaborative team with Kotlin/Java, Spring Boot, PostgreSQL, Kafka, Docker, Kubernetes and AWS experience; you will shape the technical roadmap and mentor peers while delivering real value to merchants.

Qualifications

• 5+ years of professional backend experience.
• Proficient in Kotlin or Java and Spring Boot.
• Experience with PostgreSQL, Kafka, Docker, Kubernetes, and AWS.
• Understanding of RESTful APIs and distributed/event-driven architectures.
• Experience with CI/CD pipelines and observability tools.
• Nice to have: gRPC, Protobuf, backend optimization.

Responsibilities

• Design, build, and maintain scalable backend systems for SumUp’s Bookings product.
• Collaborate with frontend and mobile teams to deliver features and APIs across web, iOS, and Android.
• Participate in planning, code reviews, and design discussions to ensure clean, testable code.
• Continuously optimise performance, ensure observability, and uphold our high reliability standards.
• Actively contribute to shaping the technical roadmap for the Sell Online platform.

Skills

Backend engineering

Kotlin / Java

Spring Boot

RESTful APIs

Distributed systems

CI/CD – GitHub Actions

Observability

Mentoring

Tools

PostgreSQL

Kafka

Docker

Kubernetes

AWS

Job description

Описание

At SumUp, we're on a mission to empower small businesses across the globe by providing a vast set of simple and affordable business tools to help them start, run, and grow their businesses. Today, over 4 million businesses in 36 markets rely on SumUp as their financial partner to manage payments, finance and customer relationships.

Задачи

• Design, build, and maintain scalable backend systems supporting SumUp’s Bookings product
• Collaborate with frontend and mobile engineers to deliver new features and improve APIs across web, iOS, and Android
• Participate in technical planning, code reviews, and design discussions to ensure clean, testable, and maintainable code
• Continuously optimise performance, ensure observability, and uphold our high reliability standards
• Actively contribute to shaping the technical roadmap for the Sell Online platform

Требования

• You have 5+ years of professional backend engineering experience
• You’re fluent in Kotlin (or Java) and have deep experience with Spring Boot
• You’ve worked with PostgreSQL, Kafka, Docker, Kubernetes, and AWS
• You understand RESTful APIs, distributed systems, and event-driven architectures (e.g. CQRS, Event Sourcing)
• You bring experience with CI/CD pipelines, GitHub Actions, and observability tools like Grafana or Honeycomb
• You thrive in collaborative teams, enjoy mentoring peers, and care about delivering real value to merchants
• Будет плюсом: Familiarity with gRPC, Protobuf, or performance optimisation at the backend/database level

Условия

• Opportunity to work from our vibrant Warsaw office in the Hala Koszyki. This involves a hybrid setup
• Commitment to Diversity and Inclusion: be part of a workplace that values and promotes diversity, fostering an inclusive environment where everyone's perspectives are respected and embraced
• Enrolment onto our Virtual Stock Option programme: you will own a stake in SumUp's future success
• A dedicated annual L&D budget of €2000 for your individual development, which can be used to attend conferences and/or advance your career through further education
• Fitness support: work out on-site at our gym or explore the city using the Multisport Card, subsidised by SumUp for access to sports facilities across Warsaw
• Commitment to well-being: access health insurance coverage for you and your family, plus life insurance to further protect your peace of mind
• Generous time off: enjoy 26 days of paid leave plus public holidays and special leave days
• Break4me: 1-month sabbatical after 3 years of service
• Referral Bonus: earn additional rewards by referring talented individuals to join the SumUp team