Senior Software Engineer — AI-Driven Payment Systems

We're a B2B payments platform (VCC, ACH, check) building a multi-tier agent architecture that replaces manual batch workflows with real-time, AI-optimized decision-making. Think ML-based scoring, decision-theoretic optimization, and human-AI collaboration — making thousands of real financial allocation decisions per day. The architecture is designed and documented. You'll join a sharp, experienced team and own the build. Day-to-day: decision engine for optimal action sequencing, real-time WebSocket infrastructure for human agents, scoring/ranking pipelines combining ML outputs with business rules, data pipelines for ML feature extraction, database migrations, event handlers, serverless functions. Stack: .NET 10, C#, DDD/CQRS/event-driven, SQL Server, AWS (Lambda, EventBridge, DynamoDB), React (internal admin UI), Python (ML scoring pipeline). We use Claude Code as a daily development tool. Looking for: strong C#/systems fundamentals, fluent with agentic co