The Opportunity

Proximity is seeking a Senior Staff Software Engineer / Engineering Lead to drive the architectural evolution of our cloud-native platform. This is a high-leverage player-coach role: you will define engineering standards, architect high-volume distributed systems, and lead a US-based team of engineers through complex technical challenges.

You’re not just a lead — you’re a technical authority. You understand what happens to a database index when a table hits a billion rows. You can diagnose why a distributed transaction failed before you even open the logs because you helped design the system and its observability. You operate with the urgency to stabilize production systems, and the long-term perspective to build a platform that scales.

Core Responsibilities

1. Architectural Strategy & Cloud Leadership

• Architect and implement scalable microservices using .NET Aspire and Azure Container Apps, ensuring reliable service discovery, resiliency, and operational simplicity.
• Design hybrid cloud data strategies, managing complex ETL pipelines between AWS S3 and Azure Data Factory that handle terabytes of data with automated retries, resilience and binary copy resumption.
• Define the "Golden Path" for development, utilizing YARP as a strategic Backend-for-Frontend (BFF) to manage traffic routing, protocol upgrades, and legacy system strangulation.

2. High-Volume Data Engineering

• Own the database architecture for high-load systems. Implement declarative partitioning (range/hash) strategies to maintain sub-millisecond query performance on datasets exceeding 1 billion rows.
• Optimize Entity Framework Core and SQL queries to ensure efficient partition pruning, preventing I/O bottlenecks.
• Manage the lifecycle of heavy data loads, ensuring zero-downtime migrations and non-blocking maintenance operations (e.g., VACUUM/ANALYZE).

3. Distributed Systems & Reliability

• Implement eventual consistency patterns using MassTransit Sagas (state machines) to orchestrate complex, long-running business transactions across microservices.
• Enforce the Transactional Outbox pattern to guarantee message reliability, idempotency, and correctness in an event-driven architecture.
• Secure the infrastructure using Azure Private Link and VNet integration, ensuring critical data stores have no public exposure.

4. Observability & Operational Excellence

• Build a world-class observability stack using OpenTelemetry (OTel), Azure Monitor, and Azure Managed Grafana.
• Define Service Level Objectives (SLOs) and create dashboards that visualize saturation, latency, and error rates to proactively identify bottlenecks.
• Lead the team through root-cause analysis and incident reviews, fostering a blameless culture that prioritizes systemic improvement over individual fault.

Qualifications

• Experience: 10+ years of software engineering experience, including 3+ years in a Lead, Staff, Principal, or architecture-focused role.
• Tech Stack: Mastery of C# /.NET 8+, Azure (Container Apps, SQL, Service Bus, ADF), and AWS (S3 integration).
• Heavy Load Expertise: Proven track record of scaling databases (PostgreSQL/SQL Server) to billions of rows. You can explain how you diagnosed and solved locking, bloat, or performance issues at scale.
• Integration Mastery: Experience with complex backend integrations. Knowledge of EDI standards (X12, NCPDP D.0) or healthcare claims processing is a major plus.
• Leadership Style: Demonstrated ability to lead remote teams, set best practices (RFCs, Code Review Standards), and mentor senior engineers.
• Work Authorization: Must be currently authorized to work in the United States without need for future sponsorship.

Compensation & Benefits

• Benefits: Comprehensive Medical, Dental, and Vision, 100% premium for employees and 25% coverage for dependents
• Culture: A focus on technical excellence, where urgency means disciplined execution — and architecture is treated as a competitive advantage.

Why Proximity

• Build technology that strengthens access to care across the U.S. healthcare system.
• Shape the architecture of a platform evolving from automation to intelligence.
• Work alongside a data-focused, mission-driven team redefining how 340B programs operate.
• Be part of an organization with a clear, unified technical vision and high expectations for engineering excellence.