Languages
Python · Rust · TypeScript / JavaScript · Kotlin · Swift · Dart · SQL · Bash
Sean McDonnell · Mansfield, Texas
Builder.
Engineer.
Owner.
Software Engineer · Python, Rust, TypeScript, and applied AI.
Origin
I learned by building things that had to work.
I’m a self-taught software engineer and the owner of NextEleven LLC. I work from Mansfield in the Dallas–Fort Worth area. Before software became the center of my work, I spent 27 years in high-trust client service as an independent tattoo artist and shop owner. That work taught me to listen closely, set expectations, iterate in public, and finish what I start.
Qualifications
The work is the credential.
I build backend systems, applied-AI workflows, retrieval tools, developer tooling, and interfaces. Recent work includes a Rust coding-agent proof of concept, a local-first Python retrieval application, a FastAPI and Next.js dealership workflow system, and a bilingual web presence for JP Transmission Recycling. I take projects through definition, implementation, testing, documentation, and handoff.
Working range
Systems
FastAPI · REST APIs · PostgreSQL / pgvector · SQLite · Redis · React · Next.js · SwiftUI · Jetpack Compose
AI / retrieval
LLM APIs · tool calling · MCP · embeddings · RAG ingestion · hybrid retrieval · reranking · citations · evaluation
Shipping / support
Docker · GitHub Actions · automated testing · CI · API integration · root-cause analysis · runbooks · release documentation
Publication record
12
Applications published on Apple’s App Store.
Built and published through NextEleven across productivity, utilities, lifestyle, commerce, wellness, and specialized operator workflows. This is a publication record only. I do not claim downloads, revenue, ratings, users, retention, or adoption from it.
Location and work
DFW base. Remote across the United States.
I’m a U.S. citizen and do not require sponsorship. I’m seeking serious software, backend, applied-AI, implementation, integration, support, developer-tooling, and automation work.