👋 About Us

At sunday, we’re transforming the dining experience with fast, seamless payments. No more waiting for the bill, with one scan, guests pay, tip, and leave. We're creating a world where time is better spent enjoying the moment.

We’re a growing team of bold thinkers, builders, and creators, working across Europe and North America to bring better hospitality to life.

💼 About the Role

We’re looking for a Staff Backend Software Engineer to help us process hundreds of millions of payments each year. This isn’t just about writing great code ; it’s about designing a solution that will match our scale for the coming years while being maintainable over time.

This role is about engineering for clarity and longevity, designing backends that are modular, observable, easy to test, and built to scale. You’ll set architectural direction, mentor engineers, drive technical alignment across teams, and help us continuously raise the bar on reliability and performance.

If you’re passionate about crafting clean architectures, simplifying complexity and building systems that power delightful user experiences and want to multiply your impact by raising the level of the entire engineering organization, we want to hear from you.

🔥 Key Responsibilities

• Lead the evolution of our service architecture, ensuring clean domain boundaries, clean interfaces, scalability, performance, and maintainability across multiple applications.
• Drive observability best practices, define metrics, traces, and logs that make our systems transparent and diagnosable.
• Promote testability and automation, ensuring high coverage and fast, reliable CI/CD pipelines.
• Led the refactoring of legacy systems and designed a comprehensive migration plan.
• Continuously improve performance and scalability, from database design to API efficiency and concurrency patterns.
• Collaborate closely with product, platform, and SRE teams to ensure our systems are resilient, observable, and cost-efficient.
• Document and share architectural decisions, creating alignment across multiple engineering teams, internal talks and documentation (ADRs, open forums, etc.)

😊 About You

• You are impact-driven: you don’t just ship features: you have a strong business / product sense and love turning ambitious ideas into scalable, elegant systems.
• You think in terms of domain boundaries, not just code files and know how to design systems that evolve gracefully.
• You thrive in fast-paced environments, but you also know when to slow down to get the architecture right.
• You take full ownership: from shaping technical solutions with product teams, through hands-on building, pairing when needed to get things done, to ensuring observability and reliability in production.
• You believe in testable, decoupled systems and see tests as enablers of speed, not blockers.You mentor others through example, helping engineers make better tradeoffs and write more maintainable systems.
• You care deeply about the “why” behind what you build, not just the “how”. You’re comfortable engaging in early product conversations and using data and customer feedback to guide decisions.
• As a staff engineer, you see your role as a force multiplier: you lead by example, mentor engineers, align teams around best practices, and drive architectural clarity across codebases.

🧠 What You Bring

• High ownership mindset and a collaborative, team-first approach and lead by example
• Also, you take full ownership: from shaping technical solutions with product teams, through hands-on building, pairing when needed to get things done, to ensuring observability and reliability in production
• Deep experience designing and building scalable back-end systems
• Strong knowledge of Hexagonal Architecture, Domain-Driven Design, or similar layered approaches.
• Practical experience in distributed systems, event-driven architectures, or microservice communication (gRPC, Kafka, Pub/Sub, etc.).
• Master of testing strategies
• Fluency with observability tools (tracing, logs, metrics)
• Strong understanding of resilience patterns (idempotency, retries, circuit breakers, caching)
• Excellent communication skills, both written and verbal.
• Proven ability to mentor engineers and align teams around a shared technical vision

🔧 Technical Edge

You don’t need to be an expert in everything, but the more of these boxes you tick, the better:

• Designing APIs with strong contracts (gRPC, Protobuf, REST) and maintaining backward compatibility
• Running performance investigation and capacity planning in high load systems
• Knowledgeable in CQRS / ES patterns
• Fluent with observability tools (Datadog, Sentry, etc.) and front-end monitoring practices.
• Understanding of accessibility and internationalization best practices.
• Knowledge of secure front-end patterns and PCI-compliant architectures.
• Understanding of edge deployments, caching, and latency optimization strategies.

🚀 Why This Role Matters

Sunday is scaling fast and with that comes complexity. We’re scaling across products, markets, and teams.This role is about bringing order and clarity to that complexity:

• Ensuring our systems are modular and maintainable.
• Making sure our architecture supports speed without sacrificing safety.
• Enabling teams to deliver confidently thanks to strong observability and testability foundations.
  

You’ll play a critical part in shaping how sunday builds and scales, helping our engineering culture mature while keeping our systems lean, fast, and resilient.

⛳️ Compensation, Perks & Benefits

• Competitive salary and equity
• Remote-first friendly culture with flexible working hours
• The chance to build products used by millions across the globe
• 100% health coverage for you and your children
• Free vacation policy
• Opportunity for significant impact in shaping data strategies and innovative product development within a high-growth environment