San Salvador · US Central Time luissfletes@gmail.com (+503) 6437-8967 LinkedIn

Summary

Twelve years shipping web products end to end, including several years with distributed US teams. Strong across Angular, React, Python, Node and .NET, with a lot of time spent on legacy migrations, defining architecture, and raising code quality on existing codebases. Currently building AI-driven products, and involved in code review and mentoring wherever I land.

Twelve years, no gaps

20142017202020232026
Employment
Freelance, in parallel

Where I've worked

Applaudo

Jul 2024 — Present

Software consultancy · Senior Full-Stack Engineer · 3 client projects

PythonFastAPIReactGemini / GCPAngularNGRX
Internal AI content generation platform generation critique synthesis confidence below threshold → refine again
  • Work across all three layers of the product: the LLM orchestration service, the product backend, and the React frontend.
  • Designed and built the agentic pipelines in Python using ReAct, reflection and planning patterns. Each stage is its own node in code calling Gemini on GCP, so the flow stays under our control rather than the model's.
  • Added a confidence score to the output, so anything below the threshold goes back for another refinement pass instead of being accepted.
  • Set up tool calling with context handed down from the backend layer, which keeps the agent away from direct database access.
  • Ship production code through an AI-assisted workflow: Figma MCP for UI that matches the design, Playwright runs to check the generated frontend against it, pytest unit tests on the Python side.
  • Proposed and pushed for the internal standards the team now uses around AI-assisted development.
AngularJS → Angular migration
  • Only engineer on the incremental migration of a legacy AngularJS app to modern Angular for a U.S. client in professional sports league applications, running both frameworks side by side through a hybrid setup while the app stayed live.
  • Moved services, components and business logic over progressively. No downtime windows, no roadmap freeze.
Government customs & tax platforms
  • Set up the frontend foundation from scratch (layouts, markup, component architecture, NGRX stores). It ended up being reused as the seed for around four other projects in the client's portfolio.
  • Worked on national-scale systems in a frontend team of around 7, alongside backend (Spring Boot), architecture, product and design.
  • Ran code reviews, built POCs to settle technical decisions, and mentored junior developers.

Freelance

2023, 2025 — Present

Independent client work, alongside full-time roles

Angular.NETSQLNestJSPostgreSQL
Two engagements

Property valuation platform · Nov 2025 — Present

  • Brought back directly by the client four years after the original build at Nativo. Ongoing full-stack development on the live platform.

MinifunKids · 2023

  • Took over the backend of an in-flight educational platform and stabilized it: added database migrations to a codebase that had none, and swapped the ORM to get versioned schema management working. Picked up NestJS on my own for this one.

Visotrust

Mar 2021 — Jun 2024

Cybersecurity SaaS, third-party risk management · Senior Frontend Engineer

Angular 9 → 16NGRXRxJSCode review
What I did there
  • Only frontend specialist on a team of five; the other four were full-stack engineers working mostly in Spring Boot. Owned the Angular architecture and reviewed every frontend PR before it merged, at least one a day and usually more.
  • Led the migration from Angular 9 to 16, refactoring roughly 80% of the codebase along the way and bringing build times down. Turning on Ivy surfaced a batch of latent problems that ViewEngine had been hiding, and working through those became a large part of the job.
  • Pushed for NGRX and implemented it in a codebase with no state management, then reworked the component architecture around smart/presentational with proper input/output contracts. Less coupling, easier to test.
  • Wrote the frontend coding standards and worked through them with the team: comments on smaller PRs, pair programming when a change needed real rework. Kept shipping features and UX improvements alongside the refactor without pausing the roadmap.

Nativo

Mar 2019 — Mar 2021

Software consultancy · Senior Full-Stack Engineer · valuation platform licensed to banks in Costa Rica

Angular.NET CoreAWS CognitoAzure DevOpsTeam lead
What I did there
  • One of two developers on the product. Defined the Angular frontend architecture from the ground up, and those patterns stayed in place with the team that grew after I left.
  • Built enterprise authentication on top of AWS Cognito and Azure DevOps to get Active Directory SSO working, which the banking clients needed before they would adopt it.
  • Wrote .NET Core APIs and handled database schema changes through migrations.
  • Also team lead for two developers on a separate project inside the company.

Stack

Frontend
Angular v9–v19, NGRX, RxJS, React, TypeScript, Material Design
Backend
Python (FastAPI, Alembic), Node.js (NestJS, Express), C# / .NET Core
AI
Agentic pipelines (ReAct, reflection, planning), LLM orchestration on GCP, tool calling, confidence-based validation, Figma MCP
Data
PostgreSQL, SQL Server, MySQL, MongoDB
Cloud
GCP, AWS (Cognito, EC2, S3, RDS), Azure DevOps, CI/CD
Testing
Playwright, Cypress, pytest, unit & E2E automation
Languages
Spanish (native), English C1, Italian B2

Earlier roles & education

OOQIA2018 — 2019
MEAN stack foundation for a fitness platform, with Auth0, Braintree and multi-tenancy.
RAIN2018
Cut ETL processing time, built React components for a stock market data platform, worked on .NET Core endpoints.
Nestrix2014 — 2018
A complete eCommerce platform end to end: backend, frontend, database design and third-party integrations.
Universidad Centroamericana2015
B.S. Systems Engineering.