EarnIn operates a real-time payments platform that has processed over $15 billion in earned wage access for millions of U.S. workers since 2013. The threat model is straightforward: financial data at scale, banking integrations with partners like Evolve Bank & Trust and Lead Bank, and transaction flows that can't afford downtime or data leakage. The company's product suite - Cash Out, Live Pay, Balance Shield, and credit monitoring - all touch sensitive payroll data, account credentials, and banking rails.
The infrastructure runs on multi-cloud architecture across AWS, GCP, and Azure, with Kafka, SNS, SQS, and Kinesis handling event streams for real-time transaction processing. The stack includes Python with Django and FastAPI for services, PostgreSQL and MySQL for transactional data, Oracle and NoSQL for other workloads, and Kubernetes for orchestration. Data processing relies on Apache Hadoop, Spark, and Databricks. Infrastructure as code is managed through Terraform, with gRPC handling internal service communication.
Security operates at the intersection of consumer fintech compliance, banking partnership requirements, and live payment processing. The architecture has to defend authentication flows, API endpoints handling payroll integrations, and database layers storing financial credentials - all while maintaining uptime for transaction processing that workers depend on between pay cycles. The team works in a regulated environment where both federal banking standards and state-level consumer protection laws define the perimeter.