Fairfax, VA · Available for the next mission

I turn complex systems into software that holds up.

I’m AJ Tatum—a senior full-stack .NET engineer and technical lead with 20+ years building, modernizing, and rescuing enterprise applications.

ARCHITECTUREENGINEERINGLEADERSHIP
AJ Tatum
IDENTITY // VERIFIEDAJ TATUMSOFTWARE ARCHITECT · TECHNICAL LEAD

THE ORIGIN STORY

Not all heroes wear capes.
Some inherit legacy code.

I’ve spent my career translating ambitious ideas and stubborn business problems into secure, maintainable software. I work across architecture and implementation, bring calm to production problems, and help teams make decisions they can still defend six months later. I especially love workflow automation—eliminating repetitive handoffs so people can focus their attention where it actually matters.

NEURAL ARCHITECTURE

ADHD is my superpower.

I’m neurodivergent, and I see that different wiring as an engineering advantage. It fuels the curiosity to keep pulling on a problem, the pattern recognition to connect details others may miss, and the hyperfocus to turn a complicated idea into a working system.

Pattern recognitionRelentless curiosityCreative problem solvingDeep-focus delivery
FIELD NOTES & EXPERIMENTSVisit ADHD Homelab
Comic-book inspired poster reading ADHD is my superpower in a developer workspace
DIFFERENT WIRING // DELIBERATE ADVANTAGE

SELECTED MISSIONS

Scattered thoughts, solid receipts.

Outcomes from healthcare, financial services, legal technology, education, and consulting.

01Optum / VA70%

Efficiency Gain

Replaced a manual, error-prone claims workflow with a PostgreSQL-backed .NET service using MediatR and domain-driven design. Automated the handoffs that used to require four people checking spreadsheets, cutting processing time 70% and manual errors 85% for a mission-critical VA healthcare system.

02OPIE Software800+

Clinics Served

Designed and built a RESTful ASP.NET Web API microservices platform from scratch on AWS, replacing a legacy Classic ASP monolith. Shipped 15 supplier integrations—including QuickBooks, Lawson, and Dynamics GP—that let clinics automate purchasing instead of re-keying orders by hand.

03Optum / VA85%

Error Reduction

Rebuilt a manual, spreadsheet-driven process into an automated .NET system with proper validation and domain rules baked in, instead of relying on people to catch mistakes after the fact. The result: an 85% drop in error rates for a mission-critical VA healthcare application, where a bad record isn’t just an inconvenience—it can affect patient care.

04Mobile Campus60K

Texts in 20 Minutes

Built a messaging platform that queued and dispatched bulk SMS across 15 university campuses without hitting carrier throttling limits—turning a multi-hour manual blast into a 20-minute automated send.

FIELD RECORD

Built in the real world.

Two decades of shipping, modernizing, and leading across healthcare, banking, legal technology, SaaS, education, and entrepreneurship.

Optum / Department of Veterans Affairs

Application Technical Lead

Architected a modern, PostgreSQL-backed healthcare application using .NET, C#, MediatR, and domain-driven design. Led and mentored four junior developers while using automation to improve operational efficiency by 70% and reduce manual errors by 85%.

LexisNexis

Application Lead

Modernized legacy .NET Framework 4.6 applications to .NET 8 and led their migration to Azure and Kubernetes. Built an event-driven solution using Azure Service Bus and Functions to extract data from incoming PDFs and persist it to SQL Server.

Huntington Bank

Technical Lead

Architected the modernization of legacy systems from .NET Framework to .NET 6, building ASP.NET Core applications and APIs around SOLID principles. Diagnosed C# and SQL performance issues, mentored junior developers, and designed management dashboards that enabled data-driven decisions.

AJ Tatum Digital

Founder / Application Technical Lead

Founded a web architecture and digital marketing consultancy that helps startups and established businesses build, maintain, and market customer-facing applications powered by Azure, event-driven architecture, and marketing automation.

OPIE Software

Senior Developer / Team Lead

Built RESTful ASP.NET Web API microservices for a healthcare SaaS platform serving more than 800 clinics, including 15 supplier integrations in an AWS-hosted environment. Helped lead the migration from Classic ASP to ASP.NET MVC and Angular while delivering integrations with QuickBooks, Lawson, and Microsoft Dynamics GP.

Academy Medical · Aaron’s · Mobile Campus

CTO / Lead Developer

Built and led technology initiatives across two startups and a major enterprise dashboard and CRM program. Delivered a company-wide CRM and SEO-driven public website at Academy Medical, KPI dashboards and internal ASP.NET/DotNetNuke tools at Aaron’s, and a messaging platform at Mobile Campus that scaled to 15 universities and delivered 60,000 messages in under 20 minutes.

THE ARSENAL

Modern engineering.
Battle-tested judgment.

I’m a full-stack technologist who has spent two decades moving fluidly between enterprise .NET architecture and scrappy self-hosted infrastructure—equally at home designing DDD systems for healthcare or wiring together n8n, databases, APIs, and Azure Functions. My toolkit spans languages, Azure and Google Cloud, CMS platforms, automation, infrastructure, analytics, and marketing technology—and keeps growing with whatever the next problem demands.

Languages

C#JavaScriptT-SQLPowerShellPython

Frameworks & Platforms

.NET 6–10ASP.NET Core / Web APIEntity FrameworkMediatRDomain-Driven DesignReactAngular

Databases

SQL ServerPostgreSQLAzure SQLCosmos DB

Cloud & DevOps

Azure App ServicesAzure FunctionsAzure DevOpsDockerKubernetesAzure Service Bus

Delivery

Git / GitHubCI/CD PipelinesAgile / Scrum

AFTER-HOURS R&D

73 workloads.
One relentlessly curious brain.

My homelab runs on curiosity, automation, and the dangerously optimistic phrase, “This should only take an hour.” It’s where ADHD-fueled rabbit holes become containers, dashboards, workflows, and occasionally an entirely redesigned network. I get to experiment, break things safely, and turn “what if?” into something useful—usually before my brain finds the next fascinating problem.

60LXC containers
12Docker applications
1Home Assistant VM
HOMELAB // SOFTWARE INDEXSELECT A SYSTEM DOMAIN
73INVENTORY
ENTRIES
ACTIVE CATEGORY

Infrastructure, Networking & Access

7 LXC1 Docker
01
AdGuard Home

https://github.com/AdguardTeam/AdGuardHome

Infrastructure, Networking & Access
LXC
02
Apt-Cacher NG

https://packages.debian.org/stable/apt-cacher-ng

Infrastructure, Networking & Access
LXC
03
authentik

https://github.com/goauthentik/authentik

Infrastructure, Networking & Access
LXC
04
Cloudflare DDNS

https://github.com/favonia/cloudflare-ddns

Infrastructure, Networking & Access
Docker
05
Docker Engine

https://github.com/moby/moby

Infrastructure, Networking & Access
LXC
06
NGINX

https://github.com/nginx/nginx

Infrastructure, Networking & Access
LXC
08
Zoraxy

https://github.com/tobychui/zoraxy

Infrastructure, Networking & Access
LXC
CORE FABRIC
Proxmox VELXCDockerDebian 12 / 13Ubuntu 22.04 / 24.04NGINXTailscale · Secure Mesh

ALLIED INTELLIGENCE

Field reports from the people in the room.

LinkedIn recommendations from managers, clients, colleagues, and people AJ has led.

AJ played a big role in finishing a proof-of-concept project under tight deadlines and changing requirements. He was able to move with agility on the project and provided good ideas to help improve and finish the project. Overall, AJ is a friendly, understanding and resourceful guy to work with and would be a good fit on many teams.
JH
Jason Hoekstra

Founder, Celerity and CenturyShield

Managed AJ directly · March 2019
01 / 17

OPERATING PRINCIPLES