MIKE HALL Principal Software Engineer / Systems Architect Chicago, IL Email: mike@just3ws.com Phone: (847) 877-3825 Website: https://www.just3ws.com LinkedIn: https://www.linkedin.com/in/just3ws/ GitHub: https://github.com/just3ws ================================================================================ PROFESSIONAL SUMMARY ================================================================================ Principal Software Engineer specializing in high-consequence legacy modernization, distributed systems architecture, and platform resilience. Combines 20+ years across software engineering and platform architecture with OpenTelemetry distributed tracing, cross-lane boundary mediation, and zero-downtime data migrations across Ruby on Rails, PostgreSQL, and cloud infrastructure. ================================================================================ CORE SKILLS ================================================================================ Platform Architecture & Legacy Modernization, Cross-Domain Boundary Architecture & Governance, OpenTelemetry & Distributed Trace Context Propagation, High-Consequence Incident Escalation & Root Cause Analysis, Zero-Downtime Data Migrations & Schema Partitioning, Ruby on Rails, PostgreSQL, Sidekiq & Redis, AWS, Docker, Kubernetes & CI/CD Pipelines, Privacy-Conscious Local AI Orchestration & Tooling ================================================================================ EXPERIENCE ================================================================================ -------------------------------------------------------------------------------- ASSOCIATE DIRECTOR, STAFF ENGINEER OneMain Financial | Remote January 2021 - February 2026 Progressed from Digital Origination Team Lead to Software Architect for the Acquisition Lane, converting to Associate Director, Staff Engineer upon corporate architecture track restructuring, while founding the ACQ Enablement team and leading the OpenTelemetry Working Group to establish the Enterprise Trace across high-volume customer acquisition flows (Rails, MuleSoft, Mainframe). Key Outcomes: * Technical Leadership & Team Consolidation: Progressed from Digital Origination Team Lead to Software Architect for the Acquisition Lane, merging two attrition-impacted teams into a unified, high-functioning engineering unit before converting to Associate Director, Staff Engineer upon corporate architecture track restructuring. * ACQ Enablement Founding & Engineering Mandates: Founded and technically led the ACQ Enablement team to protect core engineering concerns from product feature pressure: driving platform stabilization, legacy modernization, system process mapping, architecture documentation, PII remediation, and fraud investigations. * Observability & Enterprise Trace: Founded and led the OpenTelemetry Working Group (OTel WG) to establish the Enterprise Trace across high-volume customer acquisition flows, connecting a complex Rails distributed monolith, MuleSoft, and IBM mainframe backends to eliminate blind spots and align engineering around real-time service maps. * AI-Augmented Systems Investigation: Introduced privacy-conscious local AI workflows for legacy code analysis and engineering support, expanding investigative capacity while keeping human review, security constraints, and source evidence explicit. -------------------------------------------------------------------------------- DEVELOPMENT MANAGER — FOUNDER TRANSITION & ACQUISITION HANDOFF EMR-Bear, a MedSuite company | Remote May 2026 - August 2026 Conducted rapid architecture discovery, compliance verification, and operational risk assessment for a multi-tenant healthcare SaaS platform serving 130+ clinics through a founder transition and acquisition handoff. Key Outcomes: * Architecture Discovery & Operational Risk Assessment: Built a rapid 90-day system inventory and risk model spanning application codepaths, infrastructure dependencies, access boundaries, and operational risks. * Production & Compliance Governance: Established release verification gates across the deployment pipeline of a platform servicing 130+ clinics, blocking unvalidated changes prior to HIPAA compliance review and business sign-off. -------------------------------------------------------------------------------- SENIOR BACKEND DEVELOPER SK Holdings, Inc. | Chicago, IL January 2019 - December 2020 Modernized search and asynchronous messaging pipelines under live production load, executing zero-downtime Rails framework upgrades and database relational indexing. Key Outcomes: * Search Infrastructure Simplification: Replaced legacy external search clusters (Sphinx) with native MySQL full-text search and optimized relational indices, eliminating external service dependencies and reducing platform infrastructure footprint. * Zero-Downtime Platform Upgrades: Led Ruby and Rails framework upgrades across multiple core applications, sequencing database migrations and dependency updates to maintain uptime during platform modernization. -------------------------------------------------------------------------------- SENIOR SOFTWARE DEVELOPER ActiveCampaign | Chicago, IL September 2018 - December 2018 Architected the multi-database PostgreSQL and MySQL partition split, decoupling monolithic campaign dispatch queues with dual-write synchronization shims. Key Outcomes: * Legacy Boundary Isolation: Decoupled critical legacy constraints behind explicit service boundaries, eliminating high-risk direct database dependencies and establishing clean execution paths. * Data Access & Query Optimization: Replaced ad-hoc global state access with structured query patterns and multi-tier caching strategies, accelerating throughput for high-volume database reads. * Frontend Test Hardening: Hardened the Ember.js frontend test suite across complex CRM user workflows, enforcing testable state boundaries and reducing regressions in customer-facing flows. * Test-Driven Observability: Established test-driven observability patterns across legacy PHP codepaths, shortening developer feedback loops during high-risk production debugging. -------------------------------------------------------------------------------- ENGINEERING LEARNING & DEVELOPMENT BUSINESS PARTNER Groupon | Chicago, IL July 2011 - May 2013 Designed analytical fraud detection queries in Vertica, spiked anomaly detection in Clojure/Hadoop, and implemented a centralized merchant taxonomy service in Java and MySQL. Key Outcomes: * Built merchant analytics tools in Ruby and CouchDB, surfacing market insights for global sales operations. * Designed analytical fraud detection queries in Vertica and conducted exploratory spikes on Hadoop and Clojure-based anomaly detection tools. * Implemented a centralized merchant taxonomy service in Java (ActiveWeb/ActiveJDBC) and MySQL, eliminating categorization drift across distributed product teams. * Redesigned the global engineering onboarding curriculum, standardizing technical practices and shortening time-to-first-commit for new hires. -------------------------------------------------------------------------------- ADDITIONAL EXPERIENCE -------------------------------------------------------------------------------- * Senior Software Developer | BenchPrep (March 2017 - February 2018) Owned enterprise assessment workflows, leading correctness and platform security in a high-concurrency environment. * Senior Software Developer | ReachLocal (March 2015 - November 2016) Owned API design and modernization strategy, leading incremental legacy migration for a high-volume digital marketing platform. * Open-Source Transition Lead | Coderwall (January 2014 - December 2014) Hired as a contractor by the founder to lead the open-source transition of the Coderwall developer reputation platform, a Y Combinator-backed professional network for software engineers (856 GitHub stars, 304 forks). Delivered security hardening, proprietary service extraction, infrastructure modernization, and community leadership as the top contributor to the open-source codebase. * Principal Consultant | Tandem (August 2018 - August 2018) Owned strategic technical assessment and on-site operational evaluation, leading architectural realignment and scope correction for a high-risk federal software program (DoD MEPS). Brought in to an over-committed engagement following an engineering-team departure. -------------------------------------------------------------------------------- CAREER FOUNDATIONS 1999 - 2011 Built and operated enterprise integrations, transactional systems, and early web products across consulting and product organizations, establishing the production discipline and community-centered craftsmanship that still shape my leadership. * Revenue-critical commerce: Designed real-time inventory, locking, and fulfillment services for a high-volume ticket marketplace later acquired by a major industry operator. * Consulting and software craftsmanship: Delivered systems across client environments while mentoring engineers, adopting Ruby and Rails, and helping build Chicago's craftsmanship community. * Enterprise and operational systems: Built integration and operational software across large organizations, grounded in .NET, SQL, messaging, production support, and direct user needs. ================================================================================