Senior Full Stack Engineer - Sidekick

The Sidekick team builds and owns the progressive web app that SumUp's field sales agents rely on every day. As Senior Full Stack Engineer, you'll take genuine ownership of features end-to-end, from scoping through to production, working closely with product and engaging directly with sales stakeholders.

What you'll do

• Build and maintain features across the full stack of the progressive web app, spanning the field sales experience, back office tooling, and emerging LLM-powered support tooling, owning work from scoping through to production
• Participate actively in product discovery, joining user research sessions, reviewing usage data, and contributing to prioritisation discussions alongside product
• Work directly with sales stakeholders to understand their needs, distinguish between what's requested and what's actually needed, and propose solutions with clear trade-offs
• Contribute to raising engineering standards across the team through documentation, code quality, and proactive process improvements
• Integrate with external systems such as Salesforce where required, and help shape how data flows across domains

What you'll need

• Strong, proven experience with React and TypeScript, building scalable, maintainable applications in a production environment
• Hands-on experience with a full-stack framework such as Next.js, Remix, or Nuxt, with a clear track record of shipping real-world features end-to-end
• Experience building or consuming RESTful APIs and working within complex microservice systems
• Comfortable as a Kubernetes user, with exposure to working in cloud-native, distributed environments
• Experience working in a product-led or dual-track agile team alongside product, contributing to product decisions
• Natural tendency to reach out to stakeholders, ask the right questions, and bring genuine empathy to the end user's experience

What they offer

• Work from SumUp's Berlin office on large-scale fintech products used by millions globally
• Virtual Stock Option programme to own a stake in SumUp's future
• Annual L&D budget of €2,000 for conferences and professional development
• Corporate pension scheme with up to 20% employer match
• 28 days paid leave plus public holidays and special leave days
• Break4me: 1-month sabbatical after 3 years of service