Senior Software Engineer (Fintech)

TL;DR

Senior Software Engineer (Fintech): Building and optimizing real-time fraud decisioning services for international markets with an accent on distributed systems, API design, and scalable platform architecture. Focus on integrating risk vendors, operationalizing machine learning signals, and leading engineering efforts to support global expansion.

Location: Must be based in Poland

Salary: 308,000 PLN – 428,000 PLN per year

Company

Affirm is a financial technology company reinventing credit to provide consumers with flexible, transparent payment solutions without hidden fees.

What you will do

• Design and implement real-time fraud decisioning services and APIs using Python or Kotlin.
• Build and evolve platform tooling to enable rapid, repeatable fraud protection launches in new international markets.
• Integrate region-specific risk vendors and operationalize machine learning and AI signals for real-time decisioning.
• Collaborate with cross-functional stakeholders including Product, Compliance, Machine Learning, and Fraud Strategy teams.
• Support system availability through monitoring, metrics, and on-call participation.
• Foster a culture of quality by setting design standards, mentoring teammates, and leading code reviews.

Requirements

• Must be based in Poland
• 5+ years of experience building backend systems at scale using Python or Kotlin.
• Strong system design skills with experience in distributed systems, AWS, MySQL/PostgreSQL, and Kubernetes.
• Proficiency in SQL and working with data-rich environments.
• Experience with CI/CD practices and safe production deployments.
• Strong written and verbal communication skills for distributed team collaboration.

Nice to have

• Background in fraud prevention, risk systems, or real-time decisioning.
• Experience with Snowflake, dbt, Airflow, or Chronosphere.
• Experience building for multiple international markets or regions.
• Experience working in fintech or other highly regulated environments.

Culture & Benefits

• 100% subsidized medical coverage, dental, and vision for employees and dependents.
• Flexible Spending Wallets for technology, food, and lifestyle needs.
• Competitive vacation and holiday schedules.
• Learning and development programs and parental benefits.
• Employee stock purchase plan (ESPP).