Senior Software Engineer · C#/.NET · Backend + Full Stack
Jessica Haynes
I build and modernize full-stack enterprise applications — with 9+ years focused on C#/.NET backend development, APIs, and scalable architecture. Lately, I'm expanding into AI-assisted development, exploring how it can make good engineering practices even stronger.
Impact & Highlights
9+
Years of experience
95%
Faster nightly job runtime
81%
Fewer security flaws
50%
Fewer support escalations
About Me
I'm a Senior Software Engineer with 9+ years of experience building and modernizing full-stack enterprise applications, with a strong focus on C#/.NET backend development, APIs, Entity Framework, performance, and scalable architecture. I've worked across the full stack — .NET, C#, Entity Framework, MySQL, Angular, and TypeScript — while also leading technical projects, mentoring engineers, writing technical designs, and partnering closely with Product, QA, and DevOps.
Some of the problems I've enjoyed working on: reducing a high-volume background job's runtime by 95%, improving testing and observability to help achieve 6+ months of incident-free production, implementing SSO and identity integrations, and modernizing applications and development practices.
I enjoy solving complex engineering problems, improving existing systems, and learning new technologies when they're the right tool for the job — including, lately, AI-assisted development. I'm still early in that exploration, and there's more to say about it soon.
Featured Projects
PokéJudge AI
An AI-powered decision-support tool for Pokémon TCG tournament judges, built as a hands-on AI engineering project. A judge describes a rules or game-state situation in natural language; the system asks clarifying questions if needed, retrieves the relevant authoritative rules passages, and returns a cited recommendation — rating how strongly the source material actually supports it rather than presenting an unvalidated confidence score. Built in C#/ASP.NET Core, introducing each AI capability (LLM calls, structured output, retrieval-augmented generation, evaluation) only as the product needed it.
More projects coming soon
I'm actively working on the next one.
Experience
Senior Software Developer (Team Lead), 8am
Mar 2022 – Present
Austin, TX / Remote
- Led a cross-functional team of 4, driving a quality-focused culture shift that achieved 6+ months of incident-free production and a 50% drop in support escalations
- Optimized a high-volume nightly job, cutting runtime by 95%
- Spearheaded the team's adoption of agentic AI coding tools (Claude Code, GitHub Copilot), improving engineering efficiency and TDD adoption
Lead Developer, Proplanner.net
Jan 2020 – Mar 2022
Ames, IA
- Designed and supported an Identity and Access Management service, configuring SAML/OIDC connections for all clients
- Led a team that reduced security vulnerabilities by 81% across all applications
Senior Software Engineer (Team Lead), Growers Edge
Feb 2019 – Jan 2020
West Des Moines, IA
- Served as technical lead across multiple projects, owning design and delivery
- Trained and mentored junior engineers; built and deployed applications on Azure
Senior Software Developer, Proplanner.net
Dec 2017 – Feb 2019
Ames, IA
- Increased the client base by 200% by leading a platform modernization initiative
Programmer, Proplanner.net
May 2016 – Dec 2017
Ames, IA
- Developed and tested features for a .NET Windows desktop application; resolved critical issues with rapid turnaround
Let's Connect
Whether you're hiring, collaborating, or just want to talk shop — I'd love to hear from you.