Staff Backend Engineer, Fraud & Payment Risk Platform

Flex; New York (NY); Hybrid; USD 200,000 - 250,000; Full time

Benefits offered by this job

Relocation assistance

Job summary

Flex is seeking a Staff Software Engineer to build and scale our Fraud and Payment Risk Platform. You will lead the architecture and hands‑on development of backend services and shared infrastructure for fraud prevention and payment risk decisioning.

The role combines real‑time and batch processes with ML model outputs and business rules to create reliable, observable, and scalable risk capabilities. You will collaborate with product, data science, and risk policy teams to drive platform-wide

Qualifications

• 6+ years of professional software engineering experience.
• 5+ years of hands‑on Java experience, including building services with Spring Boot.
• Experience leading the architecture and delivery of complex distributed systems or shared backend platforms.
• Strong understanding of API design, service integration, data modeling, caching, and distributed‑system failure modes.
• Experience diagnosing performance bottlenecks and improving scalability and reliability through measurement, testing, and production troubleshooting.
• Experience with cloud infrastructure, containerized deployments, and relational and NoSQL data stores.
• Experience establishing observability, monitoring, and alerting for production systems.
• Ability to lead technical decisions across teams, communicate architectural trade‑offs clearly, and mentor other engineers.

Responsibilities

• Lead backend architecture and development for the Fraud and Payment Risk Platform, including decisioning services, APIs, and shared infrastructure.
• Design for scalability, performance, and reliability across services and data stores.
• Build capabilities for feature ingestion, integration, and serving for real‑time to batch features.
• Develop infrastructure for rules and experimentation with UAT, rollout, and safety controls.
• Own engineering infrastructure across the ML lifecycle, including deployment and model outputs integration.
• Own monitoring and alerting across the platform, collaborate with risk policy and data science for model behavior.
• Improve platform extensibility so teams can add features and models without duplicating infrastructure.
• Drive complex initiatives from design through production with cross‑team coordination.
• Raise the engineering bar through code reviews, mentoring, and improved testing and deployment safety.

Skills

Backend architecture

Java

Spring Boot

Cloud infrastructure

Observability

Team mentorship

API design

Distributed systems

Performance optimization

Mentoring engineers

Tools

AWS

Docker

Kubernetes

Terraform

CDK

GitHub Actions

Datadog

Snowflake

Job description

Flex is seeking a Staff Software Engineer to build and scale our Fraud and Payment Risk Platform. You will lead the architecture and hands‑on development of backend services and shared infrastructure for fraud prevention and payment risk decisioning.

The role combines real‑time and batch processes with ML model outputs and business rules to create reliable, observable, and scalable risk capabilities. You will collaborate with product, data science, and risk policy teams to drive platform-wide