Case study
AgentBeacon
An MCP server that tells me when my AI coding agents need me. Event contract, machine identity from the token, dedup and a self-hosted deployment.
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Principal Software Engineer · Puerto Rico
I design systems that ship and keep working after the demo.
I'm Lesther Ruiz. For 15 years I've built backend platforms, APIs, mobile apps and developer tools, and led the teams that ship them. Today I'm a principal engineer at Abarca Health, focused on architecture and on bringing AI into how we build software.
Work
Case studies
Two very different problems, and the decisions and trade-offs behind how I solved them.
Case study
Church App
AvailableA ready-to-brand mobile app for churches: sermons, ministries, events, map and contact in one Flutter codebase for iOS and Android.
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15 years of shipping software
The last eight years in healthcare technology at Abarca Health, and the whole time with one foot in my own products.
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Abarca Health
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Principal Software Engineer
May 2024 to Present
I lead engineering initiatives across the whole development cycle, hold the teams to enterprise standards for quality and scalability, and drive the adoption of AI-assisted development and agentic workflows.
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Lead Software Engineer
Apr 2023 to May 2024
Led a team that built and ran containerized services with Docker on Azure Kubernetes Service.
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Team Leader, Software Engineer III
Apr 2020 to Jun 2023
Led the team behind complex Angular applications that talk to many internal services through REST APIs.
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Software Engineer II, Team Lead
Oct 2018 to Apr 2020
Built and maintained web applications and started leading a small team.
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INVID
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Senior Software Developer
Jun 2016 to Oct 2018
Consultant working directly with clients: I gathered requirements, then designed and built custom solutions for them.
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Document Control Systems / Aquarius Imaging
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Software Engineer
Jan 2012 to May 2016
Built document management and imaging software on .NET, IIS and SQL Server for two sister companies.
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LR Design (BoricuaCoder)
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Founder, Software Architect, AI Systems and Digital Products
Oct 2011 to Present
My independent studio, where I build digital products, developer tools, AI systems and web and mobile apps, including TruckFinderPR and AgentBeacon.
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Education
BS in Computer Science, Cum Laude · Universidad Interamericana de Puerto Rico · 2006 to 2012
Projects
Projects and open source
BoricuaCoder.API.CoreSetup
Open source NuGet package that sets up an ASP.NET Core API with JWT authentication and Swagger/OpenAPI in a few lines.
.NET · NuGet · OAuth2
Visit
OP TCG Database
Mobile app for One Piece TCG players with advanced search and filters.
Flutter · Supabase
VisitBC-AGENTIC-OS
In developmentA shared brain for AI agents: structured roles, stage-gate approvals and persistent memory, so the work moves fast without breaking things.
AI · Agentic workflows
Writing
Writing and videos
I write about engineering leadership and building with AI, and I'm building an app on YouTube without vibe coding.
From the blog
- We Are All AI Puppeteers Now
May 2, 2026
- Clean Architecture in .NET (Without Dogma)
Feb 4, 2026
- Why a Principal Engineer Should Write
Jan 28, 2026
Stack
What I use in production
- Backend and APIs
- .NET, ASP.NET Core, Node.js, TypeScript, REST, PostgreSQL, SQL Server
- Web and mobile
- Angular, React, Astro, Flutter
- Cloud and delivery
- Azure, AKS, Docker, Cloudflare, GitHub Actions
- AI
- Claude, Agentic workflows, MCP, n8n