Software Developer

I specialize in solving complex engineering challenges, delivering scalable solutions that optimize performance, UX, and system architecture.

personal
Alexander Castro
Full-stack developer focused on scalable web and mobile solutions using TypeScript and modern JavaScript stacks. Proficient in NestJS, React, Next.js, and React Native. Experienced with AWS, GCP, Firebase, and SQL/NoSQL databases. Skilled in Tailwind CSS, Shadcn, TanStack Query, and integrating AI-powered features and LLMs.

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Experiencia

Locationmemoji
Bello, Antioquia

Technologies

I have experience in a wide range of technologies

  • HTML5
  • CSS3
  • JavaScript
  • TypeScript
  • React
  • Next.js
  • Vite
  • Tailwind CSS
  • Node.js
  • MongoDB
  • MySQL
  • Git
  • GitHub
  • Docker
  • MongoDb
  • Strapi
  • AWS
  • PostgreSQL
  • NestJS
  • Keycloak

Experience

Professional Milestones

Logali Group

Full Stack Developer
Oct 2024 - Dec 2025

Visit Logali Group
Logali Group_markGrupo Logali
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Eco2

Full Stack Developer
APR 2023 - OCT 2024

Visit Eco2
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Intech

Programing professor
Oct 2023 - Dec 2023

Visit Intech
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TICS

Technology Integrator
Jun 2023 - dic 2024

Visit TICS
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NGN

Content Creator, social media manager and mentor
Jun 2022 - dic 2022

Visit NGN
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Projects

Some of my projects

~/api-server
server running
$NestJS Modular Monolith
$Prisma + PostgreSQL
$Better Auth Sessions
$DTO Validation
$Redis/BullMQ Ready
$LATAM SaaS Architecture
NestJSPrismaPostgreSQLDockerTypeScript

Turnio API — SaaS Scheduling Backend

Turnio EcosystemAPI
  • NestJS
  • Prisma
  • PostgreSQL
  • Docker
  • TypeScript
Monolithic NestJS API for service businesses in LATAM. Includes modular domains (Auth, Business, Appointments, Clients, Services, Schedules), Prisma ORM with PostgreSQL, Better Auth session flow, DTO validation, and Redis-ready queues for async reminders.
project screenshot

Turnio Web — Booking Experience

Turnio EcosystemWeb BookingDepends on: Turnio API
  • Next.js
  • Tailwind CSS
  • TypeScript
Public booking website for Turnio where end customers can discover businesses and reserve appointments online in a clean, mobile-first flow. Designed to work alongside WhatsApp-first communication and fast onboarding for small businesses.
project screenshot
PróximamenteEn desarrollo activo

Turnio Mobile App — Owners & Staff

Pronto
Turnio EcosystemMobile AppDepends on: Turnio API
  • React
  • Expo
  • TypeScript
  • Zustand
Mobile app for business owners and workers to manage schedules, appointments and clients with an offline-first approach. Built with Expo, React Native, TypeScript, Zustand, local persistence and sync when the connection is restored. It is currently in Google Play private testing and should be available to the public in about 8 days once the mandatory test window is completed.
Coming Soon
~/api-server
server running
$MercadoPago Webhooks
$JWT Auth & RBAC
$Prisma ORM
$Docker Compose
$REST API
$Subscription Management
NestJSPrismaPostgreSQLDockerTypeScriptMercadoPago

Atlex API — Backend Services

Atlex EcosystemAPI
  • NestJS
  • Prisma
  • PostgreSQL
  • Docker
  • TypeScript
  • MercadoPago
RESTful API powering the Atlex club management platform. Built with NestJS, Prisma ORM, PostgreSQL and Docker. Features MercadoPago webhook integration for real-time payment processing, JWT authentication, role-based access control, and automated subscription management. Currently in active development.
project screenshot

Atlex 1.0 — Club Management Platform

Atlex EcosystemWeb PlatformDepends on: Atlex API
  • Next.js
  • TypeScript
  • Tailwind CSS
  • MercadoPago
Atlex is a club management platform designed to streamline administrative tasks and enhance member engagement. This project was developed using NestJs, Postgrest, Next.js, React, Tailwind CSS, and integrated with MercadoPago for seamless payment processing.
~/api-server
server running
$SSE Streaming
$Multi-Provider (Groq, Cerebras, Ollama)
$Provider Rotation
$OpenAI Message Format
$/chat Endpoint
$Vercel Deployment
BunTypeScriptOpenAI

Bun Streaming LLM API

  • Bun
  • TypeScript
  • OpenAI
Minimal Bun API that exposes a /chat endpoint with Server-Sent Events (SSE) streaming. Supports multiple LLM backends (Groq, Cerebras, and local Ollama) with provider rotation per request, making it easy to swap or compare models while keeping a single OpenAI-style message format. Deployed on Vercel.
project screenshot

Storyteller ai for kids

  • Next.js
  • Tailwind CSS
  • AWS
  • OpenAI
Storyteller is an artificial intelligence tool designed to generate stories for children. This project was created using Next.js, React, serverless, aws and Tailwind CSS.
project screenshot

MarIA - MVP | IAS Ecosystem.

  • Next.js
  • Tailwind CSS
  • Strapi
IAS management ecosystem. Created from scratch and together with the Eco2 team, using Next.js, React, strapi and Tailwind CSS.
project screenshot

Uber Clone — Ride-Hailing App

  • React
  • Expo
  • TypeScript
A modern Uber clone built to learn and demonstrate real-world ride-hailing features like real-time location tracking, trip management, and scalable app architecture. Built with Expo, React Native and Bun.
~/api-server
server running
$Multi-Tenant Architecture
$Keycloak SSO
$Role-Based Auth
$Expense Workflows
$File Uploads
$Offline Sync Support
NestJSPostgreSQLKeycloakDockerTypeScript

Workforce API — Logali Group

Workforce EcosystemAPI
  • NestJS
  • PostgreSQL
  • Keycloak
  • Docker
  • TypeScript
Multi-tenant RESTful API built for the Workforce enterprise platform. Developed with NestJS, PostgreSQL, and Keycloak for SSO authentication. Features multi-tenant data isolation, role-based authorization (technician, contractor, coordinator, accountant), work order lifecycle management, expense approval workflows, and file upload handling. Designed for offline-first mobile sync.
project screenshot

Workforce Admin — Logali Group

Workforce EcosystemWeb AdminDepends on: Workforce API
  • Next.js
  • Tailwind CSS
  • TypeScript
Web admin panel for the Workforce platform at Logali Group. Enables administrators to create and assign work orders, manage technicians, approve expenses and travel allowances, generate Excel reports from field data, assign job sites, and manage clients. Includes role-based access for coordinators and accountants. Built with Next.js, React and TypeScript.
project screenshot

Workforce — Logali Group

Workforce EcosystemMobile AppDepends on: Workforce API
  • React
  • Expo
  • Redux Toolkit
  • TypeScript
Enterprise mobile app for field workforce management with offline-first architecture. Features expense tracking, attendance, work order management, report generation with image uploads, and Keycloak authentication. Built with Expo, React Native, Redux Toolkit, and SQLite for robust offline data sync. Available on Google Play Store.
project screenshot

Like Trello app

  • Next.js
  • Tailwind CSS
  • AWS
Like Trello is a web app that allows you to create boards, lists and cards. This project was created using next js, aws amplify, dynamoDB, tailwind CSS. I stopped working the BD because of the cost, but if you want i can re-enable it, just let me know.
project screenshot

Courses Landing Page

  • Next.js
  • Tailwind CSS
Landing page for a course platform. This project was created using Next js, Tailwind CSS.
project screenshot

CopyGenius - Co:here Hackaton 2023

  • Next.js
  • Tailwind CSS
CopyGenius is an artificial intelligence tool designed to generate effective marketing copy, it also integrates other functionality to create product descriptions. CopeGinius web app created using next js, in order to participate in the co:here hackaton of midudev. Actually is not working bacause need to pay the API.
project screenshot

Encripter app

  • Tailwind CSS
  • React
Encripter app is a web app that allows you to encrypt and decrypt messages using the Caesar cipher. This project was created using React, Tailwind CSS and Github pages.
project screenshot

Metacritic Clone

  • Tailwind CSS
  • React
Metacritic clone is a mobile app, web app that allows you to search for movies and series, see their ratings and reviews. This project was created using React native, Natiwind CSS.
project screenshot

Calculator clone

  • React
Calculator clone is a mobile app, web app that allows you to perform basic mathematical operations. This project was created using React native

Contact

Get in touch with me