Senior Backend Engineer, International Eng

Whatnot Whatnot · Consumer · Kraków, Poland · Engineering

Senior Backend Engineer for Whatnot's International Engineering team, focusing on building scalable systems for cross-border transactions, tax/regulatory compliance, and international post-purchase experiences. Requires strong backend, distributed systems, and Python/Go experience.

What you'd actually do

  1. Building VAT tooling and seller-facing tax infrastructure for EU and UK markets
  2. Designing cross-border shipping and Delivered Duty Paid (DDP) experiences that enable international commerce
  3. Building systems to support market-specific requirements including Right of Withdrawal, refund automation, and regulatory compliance. Expanding Seller Protection Systems (SPS) into international markets
  4. Developing operational tooling that enables efficient international marketplace operations
  5. Partnering with internal logistics, payments, and platform teams to build durable long-term infrastructure

Skills

Required

  • 5+ years of professional software engineering experience
  • Strong backend engineering experience in distributed systems or large-scale platforms
  • Experience designing, operating, and scaling reliable production services
  • Strong proficiency in Python or Go
  • Experience working with relational databases and event-driven architectures
  • Ability to drive projects independently from ambiguous problem statements to production launch
  • Excellent communication skills and ability to collaborate across engineering, product, operations, and business stakeholders

Nice to have

  • Experience with payments, fintech, e-commerce, logistics, marketplace platforms, or compliance systems
  • Experience building operational platforms, workflow systems, or transaction processing infrastructure
  • Experience working in rapidly growing product organizations

What the JD emphasized

  • regulatory compliance
  • compliance systems