Senior Backend Engineer — Global Transactions & Tax Infra

Whatnot; Kraków; On-site; PLN 100,000 - 130,000; Full time

Job summary

Whatnot is looking for a Senior Backend Engineer in Kraków, Poland, to design and build highly scalable systems supporting millions of transactions across multiple countries. The role focuses on backend engineering, requiring strong proficiency in Python or Go, and experience with relational databases.

Responsibilities include developing operational tooling for marketplace operations and ensuring tax compliance. Candidates should have over 5 years of software engineering experience and excellent communication skills to collaborate across teams.

Qualifications

• 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.

Responsibilities

• Design and build systems that support millions of transactions.
• Develop operational tooling for efficient international marketplace operations.
• Create cross-border transaction infrastructure.

Skills

Backend engineering in distributed systems

Proficiency in Python

Strong communication skills

Tools

Relational databases

Event-driven architectures

Job description

Whatnot is looking for a Senior Backend Engineer in Kraków, Poland, to design and build highly scalable systems supporting millions of transactions across multiple countries. The role focuses on backend engineering, requiring strong proficiency in Python or Go, and experience with relational databases.

Responsibilities include developing operational tooling for marketplace operations and ensuring tax compliance. Candidates should have over 5 years of software engineering experience and excellent communication skills to collaborate across teams.