# Mike Hall
Principal Software Engineer

## Summary
Principal Software Engineer who modernizes high-consequence production systems. Helps engineering leaders make confident decisions about aging architectures by establishing clear domain ownership, OpenTelemetry distributed tracing, zero-downtime safety, and practical AI engineering across Ruby on Rails, PostgreSQL, and cloud infrastructure.

## Skills
- Cross-Team Technical Leadership
- Platform Architecture & Legacy Modernization
- Production Systems & Reliability
- System Cartography & Knowledge Recovery
- Incident Response & Root Cause Analysis
- Observability & OpenTelemetry
- Distributed Systems & Async Processing
- Data Integrity & Performance
- Platform Enablement & Developer Productivity
- AI-Augmented Engineering & Automation
- Ruby on Rails
- PostgreSQL & SQL
- Sidekiq & Redis
- AWS, Kubernetes & Docker
- CI/CD

## Experience

### Development Manager at EMR-Bear, a MedSuite company
**May 2026 — August 2026**

Engaged on a bounded 90-day interim assignment to conduct rapid system cartography and operational risk assessment for a multi-tenant healthcare SaaS platform serving 130+ clinics following a founder transition.

**Key Outcomes:**
- Architectural & Risk Cartography: Built a rapid 90-day system inventory and risk model spanning application codepaths, infrastructure dependencies, access boundaries, and operational risks.
- Production & Compliance Governance: Protected production stability across 130+ clinical environments by establishing release verification gates across the deployment pipeline, blocking unvalidated changes prior to HIPAA compliance review and business sign-off.
- Engineering Continuity: Created transparent component ownership, visible operational priorities, and collaborative decision rhythms for a distributed U.S.-Mexico engineering team.

**Skills:** Technical Leadership, System Cartography, Rapid Risk Assessment, Production Governance, Ruby on Rails, Kubernetes, Production Observability, Security & Risk Analysis, Distributed Team Collaboration

### Associate Director, Staff Engineer at OneMain Financial
**January 2021 — February 2026**

Served as Senior Technical IC and Software Architecture Lead for the Acquisition lane of a regulated financial enterprise, combining hands-on system cartography with production stability, modernization, observability, and cross-team technical direction.


**Key Outcomes:**
- Full-Stack Dependency Cartography: Reconstructed end-to-end customer journeys spanning browser interaction surfaces, API gateways, application middleware, and legacy database layers, establishing a unified operational risk model for incident response and change governance.

- Incident Response & Technical Escalation: Served as final escalation point for high-severity outages, translating live root-cause investigations into stronger telemetry, explicit component ownership, and reusable system knowledge.

- Lateral State Coupling De-risking: Refactored fragile multi-step Rails workflow state machines, eliminating hidden lateral state mutations across asynchronous boundaries and resolving persistent data integrity failures in core acquisition flows.

- Platform Enablement & Responsibility Realignment: Realigned Acquisition engineering around explicit business boundaries, then founded and technically led ACQ Enablement to protect platform reliability, remediation, and modernization work from feature pressure.

- Observability & Boundary Instrumentation: Founded and led an enterprise OpenTelemetry initiative, instrumenting legacy microservices and third-party API supply-chain boundaries to convert dark system behavior into quantifiable telemetry and reduced MTTD.

- 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.


**Skills:** Cross-Team Technical Leadership, Platform Architecture, System Cartography, Lateral State Dependency Mapping, System Resilience, Incident Leadership, Observability, OpenTelemetry, Legacy System Modernization, Distributed Systems, Ruby on Rails, PostgreSQL, AWS

### Senior Backend Developer at SK Holdings, Inc.
**January 2019 — December 2020**

Led backend stability, performance, and modernization for high-traffic Rails products, improving full-text search, campaign delivery pipelines, and data layer reliability while systems remained under production load.


**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.

- High-Volume Messaging Pipelines: Designed and validated asynchronous batch delivery pipelines via SendGrid and Sidekiq, enforcing IP warmup protocols and deliverability safety for large-scale campaign operations.

- Data Engine & Analytics: Engineered complex relational analytical queries across multi-million row content catalogs, powering real-time data visualizations and international media publishing.

- 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.


**Skills:** Ruby on Rails, MySQL, Full-Text Search, Redis, Sidekiq, SendGrid Async Pipelines, Data Analytics & SQL, CI/CD, System Observability, Backend Architecture

### Senior Software Developer at ActiveCampaign
**September 2018 — December 2018**

Owned core system testability and performance at scale, leading legacy modernization in a highly coupled CRM platform.

**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.

**Skills:** PHP, MySQL, Ember.js, JavaScript, Legacy System Modernization, Backend System Architecture, Automated Testing, Performance Optimization

### Principal Consultant at 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).


**Key Outcomes:**
- Conducted an on-site, end-to-end operational walkthrough at military processing facilities (Des Plaines MEPS), identifying critical disconnects between enlistment workflows and proposed software models.

- Evaluated program viability and delivered definitive architectural recommendations directly to executive leadership, mitigating severe contractual and delivery risks.


**Skills:** System Resilience, Platform Architecture, Federal Software Assessment, Operational Field Research

### Senior Software Developer at BenchPrep
**March 2017 — February 2018**

Owned enterprise assessment workflows, leading correctness and platform security in a high-concurrency environment.

**Key Outcomes:**
- Critical assessment calculation errors were addressed by analyzing and optimizing complex PostgreSQL queries, improving accuracy and reducing response times.
- Vulnerable submission pipelines were addressed by implementing JWT-based response verification, preventing tampering and enforcing once-only processing.
- Unsafe third-party integrations were addressed by designing a secure cross-origin API for embedded clients, establishing explicit trust boundaries.
- High-concurrency performance bottlenecks were addressed by optimizing database interactions, reducing operational risk under heavy load.
- Rework and unclear requirements were addressed by introducing lightweight team practices, improving delivery reliability.

**Skills:** Ruby, Ruby on Rails, PostgreSQL, JWT Authentication, Backend System Architecture, Secure API Design, Database Performance Optimization, Observability and Logging

### Senior Software Developer at ReachLocal
**March 2015 — November 2016**

Owned API design and modernization strategy, leading incremental legacy migration for a high-volume digital marketing platform.

**Key Outcomes:**
- A high-risk legacy rewrite was addressed by evaluating feasibility and proposing an incremental modernization strategy, preventing a massive project failure.
- Tight backend constraints were addressed by designing a two-tier frontend architecture, separating user experience iteration from legacy system limitations.
- Brittle internal integrations were addressed by designing and building an API Gateway, safely exposing selected internal services through secure interfaces.
- Operational and maintenance risks were addressed by introducing code quality and security tooling, improving platform reliability.

**Skills:** Platform Architecture, API Gateway Design, Ruby on Rails, PostgreSQL, React, Redis, Legacy System Modernization, Secure API Design, Data Migration Strategy

### CTO at KloboMedia
**March 2014 — September 2016**

Owned end-to-end platform architecture, leading high-throughput data integration for an early-stage social media startup.

**Key Outcomes:**
- Evolving third-party API constraints were addressed by architecting a resilient platform integrating Twitter, Facebook, and Instagram APIs, enabling unified social impact measurement.
- High-volume data processing bottlenecks were addressed by designing a high-throughput pipeline using Sidekiq Enterprise, generating real-time recommendations.
- Heterogeneous social media data was addressed by implementing a PostgreSQL JSONB storage strategy, enabling flexible querying.
- Multi-cloud infrastructure needs were addressed by building and securing production environments across DigitalOcean, Heroku, and AWS with automated deployment pipelines.

**Skills:** Ruby, Ruby on Rails, PostgreSQL, Redis, Sidekiq, Amazon RDS, Heroku, DigitalOcean, Twitter API, Facebook Graph API, Instagram API

### Core Team Lead at Coderwall
**January 2014 — December 2014**

Owned platform modernization and open-source transition, leading infrastructure cost reduction in a community-driven ecosystem.

**Key Outcomes:**
- High background processing costs on Heroku were addressed by replacing Resque with Sidekiq, materially reducing operational overhead.
- Complex and costly data queries were addressed by migrating from MongoDB to PostgreSQL, simplifying the technical stack and improving maintainability.
- Unstable search performance was addressed by upgrading and optimizing Elasticsearch queries, improving search relevance.
- Stagnant proprietary growth was addressed by relaunching the platform as an open-source project, guiding a diverse contributor community.

**Skills:** Ruby, Ruby on Rails, PostgreSQL, Redis, Sidekiq, ElasticSearch, AWS S3, Heroku, JavaScript, Backbone.js, MongoDB

### Senior Software Developer at Upcity
**October 2013 — February 2014**

Owned payment integrations and local development infrastructure, leading system modernization for an SOA-based marketing platform.

**Key Outcomes:**
- Missing subscription capabilities were addressed by integrating the Chargify payment system as a backend and lightweight CMS, enabling paid plans and self-serve updates.
- Inconsistent and slow developer onboarding was addressed by implementing a multi-VM Vagrant environment, replicating the production stack and eliminating environment drift.

**Skills:** Ruby, Ruby on Rails, PostgreSQL, Redis, Sidekiq, Riak, Vagrant, NGINX, Capistrano, Bash, Ubuntu

### Senior Software Developer at Viewpoints
**May 2013 — October 2013**

Owned core business system development, leading AWS deployment modernization and CI implementation.

**Key Outcomes:**
- The lack of targeted monetization was addressed by implementing custom tracking and marketing tools, enabling a new revenue stream for the platform.
- Risky and unstable shared environments were addressed by building standardized testing and development environments, enabling reliable continuous integration.
- Instability during high-demand periods was addressed by streamlining the AWS deployment pipelines and server images, enabling robust scaling.

**Skills:** Ruby, Ruby on Rails, AWS EC2, AWS RDS, PostgreSQL, Redis, Resque, Capistrano, NGINX, Sidekiq, Logentries

### Engineering Learning & Development Business Partner at Groupon
**July 2011 — May 2013**

Owned core backend systems for fraud and taxonomy, leading global engineering enablement during hyper-growth.

**Key Outcomes:**
- Siloed merchant data was addressed by building analysis tools in Ruby and CouchDB, generating reports to identify high-value markets.
- Unscalable fraud detection was addressed by designing pattern queries in Vertica and Hadoop detection tools, scaling analysis throughput by 10x.
- Fragmented merchant categorization was addressed by implementing a centralized taxonomy service in Java and MySQL, reducing categorization drift across product teams.
- Inconsistent engineering ramp-up was addressed by redesigning the global onboarding program, modernizing training consistency across multiple sites.

**Skills:** Ruby, Java, Clojure, CouchDB, Vertica, Hadoop, MySQL, Redis, JavaScript, Bash

### Software Engineer at Obtiva
**August 2009 — July 2011**

Delivered backend systems and services as a consultant across multiple clients, including Sears, Leapfrog Online, and Groupon, supporting early-stage scaling and data-driven operations in high-growth environments.


**Key Outcomes:**
- Limited access to business-critical data was addressed by building self-service reporting systems for Leapfrog Online, enabling stakeholders to generate and analyze data warehouse reports without engineering intervention.

- Gaps in B2B sales capabilities were resolved by implementing a commercial sales and catalog service for Sears, enabling new revenue workflows for enterprise customers.

- Instability during rapid scaling at Groupon was mitigated by contributing to deals services and fraud analysis systems, supporting platform reliability under high-growth traffic conditions.


**Skills:** C#, Ruby, Ruby on Rails, JavaScript, SQL Server, MySQL, Git, RSpec, Resque, NGINX

### Principal Developer at Business Decisions, Inc.
**October 2008 — August 2009**

Owned all technical strategy and system development, leading lifecycle modernization for multi-firm consulting teams.

**Key Outcomes:**
- High delivery risk from fragmented teams was addressed by leading technical strategy and end-to-end development, establishing consistent delivery practices.
- Manual integration processes were addressed by introducing Subversion and CruiseControl.NET, modernizing the development lifecycle and improving code quality.
- High onboarding overhead was addressed by engineering standardized VMWare development environments, significantly reducing time-to-productivity for external contractors.

**Skills:** C#, ASP.NET, Microsoft SQL Server, Subversion, CruiseControl.NET, VMWare, IIS, JavaScript, JSON

### Assistant Vice President, Application Developer at JPMorgan Chase & Co.
**April 2008 — October 2008**

Owned cross-system integration stability, leading defect resolution in regulated financial workflows.

**Key Outcomes:**
- Critical cross-system integration failures were addressed by debugging complex SOAP-based distributed architectures, restoring reliability to high-stakes financial workflows.
- Pervasive data desynchronization was addressed by identifying and resolving root causes between .NET services and legacy mainframes, improving financial reporting accuracy for enterprise clients.

**Skills:** C#, ASP.NET, SOAP, XML, Microsoft SQL Server, Transact-SQL (T-SQL), Visual Basic .NET (VB.NET), JSON

### Senior .NET Developer at Brightstar Corporation
**March 2007 — April 2008**

Owned enterprise supply-chain integration, leading cross-system data unification for a global mobile device distributor.

**Key Outcomes:**
- Fragmented purchase order data was addressed by orchestrating a complex enterprise integration using BizTalk, unifying sales, inventory, and financial systems.
- Opaque supply-chain lifecycles were addressed by designing and implementing an executive dashboard, enabling real-time and data-driven decision-making.
- Disconnected financial platforms were addressed by integrating Solomon software with custom applications using SubSonic ORM and advanced T-SQL, eliminating manual data reconciliation.

**Skills:** C#, ASP.NET, Microsoft BizTalk Server, Microsoft SQL Server, SubSonic ORM, Solomon Accounting Software, Transact-SQL (T-SQL), XML, SOAP

### Senior .NET Developer at TicketsNow
**November 2005 — March 2007**

Owned real-time inventory systems, leading transactional integrity and iterative delivery for revenue-critical operations.

**Key Outcomes:**
- Concurrent duplicate sales of high-demand tickets were addressed by architecting a real-time inventory locking service, generating $2M+ in incremental revenue.
- Lack of iterative execution was addressed by establishing Scrum practices for the Real-Time team, institutionalizing cross-functional coordination and delivery predictability.

**Skills:** C#, ASP.NET, Microsoft BizTalk Server, Microsoft SQL Server, Scrum, Transact-SQL (T-SQL), SOAP, CodeSmith API, JSON, JavaScript

### Senior Software Developer at BP
**June 2005 — November 2005**

Owned critical feature enhancements for an industrial invoicing system, leading performance optimization in high-volume billing workflows.

**Key Outcomes:**
- Complex billing workflow constraints were addressed by engineering core feature enhancements using VB.NET, improving system responsiveness.
- High-latency financial data processing was addressed by redesigning stored procedures and optimizing SQL Server data access patterns, reducing latency in critical billing cycles.

**Skills:** ASP.NET, C#, Microsoft SQL Server, Transact-SQL (T-SQL), Visual Basic .NET (VB.NET), Windows Server

### Senior Software Developer at Motorola
**August 2004 — May 2005**

Owned retail feature delivery, leading iterative execution in a complex enterprise sales portfolio application.

**Key Outcomes:**
- High-friction enterprise delivery was addressed by championing Scrum methodologies, improving predictability and managing organizational expectations.
- Complex retail operational requirements were addressed by delivering key portfolio features using .NET and SQL Server, supporting high-traffic sales operations.

**Skills:** C#, ASP.NET, Microsoft SQL Server, SOAP, Scrum, Transact-SQL (T-SQL), XML

### Software Developer at Riverpoint Group
**July 2004 — August 2004**

Owned reusable UI component architecture, leading frontend delivery for a personal health monitoring platform.

**Key Outcomes:**
- Inconsistent patient-facing modules were addressed by developing reusable ASP.NET Web Forms components, improving development consistency and speed.
- Sluggish real-time health visualization was addressed by optimizing database interactions in SQL Server, ensuring high-performance metric delivery.

**Skills:** ASP.NET, C#, Microsoft SQL Server, JavaScript, HTML, CSS

### Programmer Analyst at Integrated Performance Solutions, Inc.
**November 2003 — July 2004**

Owned dynamic reporting architecture, leading the platform transition from classic ASP to .NET environments.

**Key Outcomes:**
- Rigid legacy reporting was addressed by developing a custom report rules engine and interface, empowering end-users to generate dynamic reports without engineering intervention.
- Complex data modeling constraints were addressed by engineering a dynamic SQL rules wizard leveraging early JSON techniques, facilitating flexible reporting.
- Outdated technical architecture was addressed by leading the migration of legacy reporting widgets to ASP.NET Web Forms, establishing early .NET architectural patterns.

**Skills:** ASP.NET, Active Server Pages (ASP), JavaScript, JSON, Microsoft SQL Server, Transact-SQL (T-SQL), Visual Studio .NET, CSS

### Programmer Analyst at New Labor Strategies, Inc.
**June 2002 — November 2003**

Owned kiosk-based HR modules, leading frontend modernization for high-friction factory floor environments.

**Key Outcomes:**
- Specialized factory floor accessibility requirements were addressed by engineering custom touch-screen keyboards and job bidding modules, enhancing kiosk utility for staff.
- Sluggish legacy system performance was addressed by modernizing the VBScript codebase with client-side JavaScript, improving UI responsiveness.

**Skills:** Active Server Pages (ASP), VBScript, JavaScript, Microsoft SQL Server, CSS, HTML

### Software Developer at Trippe Manufacturing, Inc.
**October 2001 — December 2001**

Owned sales lead tracking systems, leading data automation and business continuity during a high-risk vendor transition.

**Key Outcomes:**
- Error-prone manual lead data ingestion was addressed by engineering a sophisticated spreadsheet transformation engine, significantly reducing data entry errors.
- Critical project risk from vendor exit was addressed by transitioning to a direct advisory role, maintaining business continuity for sales tracking systems.

**Skills:** Microsoft Access, Visual Basic, Visual Basic for Applications (VBA), Visual SourceSafe

### Application Analyst at Sentinel Technologies, Inc.
**July 2000 — October 2001**

Owned custom web delivery and early OCR prototyping, leading cross-platform implementations for enterprise clients.

**Key Outcomes:**
- Complex semi-structured receipt data was addressed by designing an early-stage OCR pipeline using awk and sed, successfully digitizing large volumes into a database.
- Diverse legacy enterprise requirements were addressed by delivering custom web applications across multiple stacks for high-profile clients including Harley-Davidson.

**Skills:** Java, Active Server Pages (ASP), Microsoft SQL Server, JavaScript, HTML, CSS, VBScript

### System Administrator at C.H. Robinson
**December 1999 — July 2000**

Owned critical site infrastructure, leading early logistics workflow automation in a high-availability environment.

**Key Outcomes:**
- Legacy site infrastructure risks were addressed by managing hardware and system upgrades, ensuring 24/7 availability for regional transportation management.
- Manual workflow friction was addressed by prototyping an automated shipment booking solution, establishing a technical roadmap for logistics modernization.

**Skills:** Windows NT, Windows 98