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Néstor Castelblanco
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Hi, I'm

Néstor
Castelblanco

Junior Full-Stack Developer — Java, TypeScript, React

I build web systems end to end, from the data model to deployment. Two of them are already in production at an education provider in Colombia.

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Monthly commits across my repositories

717 commits from Sep 2023 to Oct 2026

Counted from git, public and private
Monthly commits across my repositories
Sep 202315
Oct 202361
Nov 202325
Apr 20241
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Apr 202538
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Oct 202652

Featured projects

Ordered by relevance. Private projects are described at a high level, with no code or internal data.

  • In production
  • Professional
  • 2026

SIGESAC

Request tracking and audit trail for an education provider

A web platform that replaces WhatsApp, phone calls, email and spreadsheets with a single system where every request or complaint has a tracking number, an owner, a deadline and an auditable history.

Problem
Customer requests arrived through scattered channels, with no clear owner, no response-time control and no reporting.
My role
Built end to end as the sole author: domain model, REST API, frontend, security, tests, pipelines, deployment and technical documentation.
  • In production
  • 52 REST endpoints
  • 4 roles with RBAC
  • State machine with SLAs
  • 5 documented ADRs
Read the case study: SIGESACVisit sitePrivate repository
sigesac.sysdatec.edu.co/radicar
SIGESAC's public form for filing an anonymous request, with type, subject, category, description and attachments.
Anonymous filing, a public page in production.
Architecture: SIGESAC

  1. Web client

    • React 18 SPAVite + Tailwind
    • React RouterRole-protected routes
    • AxiosAttaches the JWT
  2. → HTTPS · JSON · JWT

  3. REST API · Spring Boot 3

    • 12 controllers@PreAuthorize authorization
    • ServicesRules and state machine
    • VencimientoSchedulerFlags overdue by SLA
  4. → JPA / Hibernate

  5. Persistence

    • Spring Data JPA14 entities
    • PostgreSQL 16Relational store
    • FlywayVersioned migrations

Cross-cutting concerns

  • Security

    • JwtAuthenticationFilter
    • RBAC, 4 roles

  • Auditing

    • AOP @Auditable
    • Historial de negocio

  • Integrations

    • SMTP, correo HTML
    • Adjuntos validados

  • Delivery

    • GitHub Actions
    • Jenkins + SonarQube
  • In production
  • Professional
  • 2026

GPE — Gestión de Prácticas Empresariales

A production system for the full internship lifecycle

A platform that digitizes internships at a technical institute: job postings, applications, requirements, occupational insurance, follow-up visits, hour logs, reports, signatures and certificates.

Problem
The process ran on paper forms and spreadsheets, with five roles (coordination, management, administration, students and company tutors) who had to approve, return and sign things in order.
My role
Sole author: functional analysis, data model, backend, frontend, document generation, deployment and ongoing changes driven by the institute's real business rules.
  • In production
  • 66 data models
  • 33 backend modules
  • 20 PDF templates
  • 207 commits
Read the case study: GPE — Gestión de Prácticas EmpresarialesVisit sitePrivate repository
gpe.sysdatec.edu.co
Public internship portal with entry points for companies, students and staff, and counts of partner companies and students in placement.
Public internship portal, in production.
Architecture: GPE — Gestión de Prácticas Empresariales

  1. Web client

    • React 18 + TypeScriptVite + Radix UI
    • TanStack QueryServer-state cache
    • React Hook Form + ZodValidated forms
  2. → HTTPS · JSON · JWT

  3. REST API · Express + TS

    • 33 módulos verticalesrouter → controller → service
    • MiddlewaresAuth, RBAC, uploads, errors
    • Esquemas ZodInput validation
  4. → Prisma Client

  5. Persistence

    • Prisma ORM66 models, migrations
    • PostgreSQLRelational store
    • StorageServiceFiles, swappable backend

Cross-cutting concerns

  • Documents

    • Handlebars + Puppeteer
    • 20 plantillas PDF

  • Scheduled jobs

    • node-cron diario
    • Recordatorios y alertas

  • Notifications

    • Nodemailer (SMTP)
    • En plataforma

  • Auditing

    • AuditLog
    • Antes y después
  • In production
  • Professional
  • 2026

Fondo Ciudad Torres Blancas 2027

Official site for a cycling gran fondo in El Líbano, Tolima

Site for the FCTB 2027 event with routes, rider kit, schedule, registration and FAQ, plus a rider's guide with hotels, rural tourism, trails, local guides and travel tips.

Problem
The organizers had their information spread across a spreadsheet, a scanned 40-page PDF and details still to be confirmed. They needed a site that's fast on phones and can be updated without redesigning anything.
My role
Designed and built end to end as the sole author: visual identity derived from the logo, typed content, data import, tests and launch.
  • In production
  • 2 pages, 11 sections
  • 45 unit tests
  • E2E at 7 widths
  • Automated WCAG 2.2 AA
Read the case study: Fondo Ciudad Torres Blancas 2027Visit sitePrivate repository
fondociudadtorresblancas.org
FCTB 2027 home page with the line “Every mountain has a story. Write yours”, start date, venue, altitude and countdown.
Home page, in production.
Architecture: Fondo Ciudad Torres Blancas 2027

  1. Content

    • src/configEvent and env vars
    • src/dataOne source per section
    • directory.jsonGenerated from the spreadsheet
  2. → props tipadas

  3. Interface · React 19

    • 11 seccionesComponents hold no data
    • useGpxTrackProfile and map from GPX
    • Motion (LazyMotion)Honors reduced motion
  4. → vite build

  5. Build and quality

    • Vite2 HTML entries + sitemap
    • Vitest45 unit tests
    • Playwright + axe7 widths, WCAG 2.2 AA

Cross-cutting concerns

  • Data import

    • Excel → directory.json
    • Script en Python

  • Images

    • WebP 640 / 1280 / 1920
    • Manifiesto de tamaños

  • Routes

    • Lectura de GPX
    • Haversine y desnivel

  • SEO

    • HTML por página
    • Open Graph y sitemap
app-frontend-unieventos.web.app
UniEventos landing page with the welcome message, platform description and its features.
Landing page deployed on Firebase Hosting.
  • Completed
  • Academic
  • Team of 3
  • 2024

UniEventos

Event ticketing with online payments and QR codes

A platform to publish events with seating tiers, manage a cart and coupons, pay through Mercado Pago and receive the order by email with a QR code.

Architecture: UniEventos

  1. Client

    • Angular 18
    • Guards
    • Interceptor
  2. → JWT

  3. API

    • Spring Boot
    • 4 controllers
    • Filtro JWT
  4. → Mongo

  5. Data

    • Spring Data
    • MongoDB
  • Mercado Pago payments
  • Orders with QR codes
  • Coupons and cart
  • Admin panel
Backend codeFrontend code
localhost
Car system sign-in screen with email and password fields and a link to create an account.
Sign-in screen, local build.
  • Completed
  • Personal
  • 2026

Gestión de Autos

Full-stack technical test with JWT authentication

An app where each user registers and manages their vehicles, with a protected REST API and a React frontend.

Architecture: Gestión de Autos

  1. Client

    • React + Vite
    • Axios
  2. → JWT

  3. API

    • /auth
    • /cars
    • Filtro JWT
  4. → JPA

  5. Data

    • JPA
    • SQL Server
  • JWT-protected API
  • User → cars relationship
  • Backend tests
Backend codeFrontend code

Profile

I'm a final-year Systems Engineering student at Universidad del Quindío, and I work as a developer and instructor at Sysdatec.

I focus on business applications: systems with roles, approval workflows, audit trails and business rules that keep changing once real people use them. On the backend I work with Java/Spring Boot and Node.js/TypeScript, and on the frontend with React.

Before writing code, I model the domain and write down the important decisions. I test what's most likely to break, like security and state machines, and let CI pipelines run the checks.

I'm looking for my first full-stack or backend role on a team where I can contribute from day one and keep growing with solid engineering practices.

Experience and education

Work experience

  1. Present

    Full-stack web developer and digital project manager

    Sysdatec Centro de Desarrollo Integral S.A.S.

    • Designed, built and deployed the internship management system (GPE), now in production.
    • Built and deployed SIGESAC, the institute's request and complaint management system, also in production.
    • Built Sysdatec's institutional website, with a CMS, analytics and SEO.
    • Built the Red Académica platform for Universidad del Quindío and websites for other organizations.
    • Owned each project's full cycle: planning, design, development, testing and deployment.

  2. Present

    Technical training instructor

    Sysdatec Centro de Desarrollo Integral S.A.S., Líbano, Tolima

    • Teach Databases, Programming Logic and Web Development in vocational software development programs.
    • Design competency-based online and in-person content, and build course modules on the Q10 platform.
    • Advise final projects and take part in curriculum improvement.

Education

  1. 10th semester · graduation pending

    B.Eng. in Systems and Computer Engineering

    Universidad del Quindío, Armenia, Quindío

    • Coursework projects in advanced programming, databases, graph theory and algorithm analysis.

Certifications

No certifications to list yet.

Stack, with evidence

Only technologies I've shipped in my own projects. Each one shows where it's used.

Backend

Java · Spring Boot
Used in: SIGESAC, UniEventos, Gestión de Autos, ShopSystem
Spring Security · JWT
Used in: SIGESAC, Gestión de Autos, UniEventos
Node.js · Express
Used in: GPE
Python
Used in: FCTB, Bibliometría automática

Frontend

React
Used in: SIGESAC, GPE, FCTB, Gestión de Autos
TypeScript
Used in: GPE, FCTB
Angular
Used in: UniEventos
Tailwind CSS
Used in: SIGESAC, GPE, FCTB
TanStack Query · React Hook Form · Zod
Used in: GPE

Databases

PostgreSQL
Used in: SIGESAC, GPE, Bibliometría automática
Prisma
Used in: GPE
JPA · Hibernate · Flyway
Used in: SIGESAC, Gestión de Autos
MongoDB
Used in: UniEventos, ShopSystem
SQL Server
Used in: Gestión de Autos
Oracle · PL/SQL
Used in: Bases de datos

Testing and quality

JUnit 5 · Mockito
Used in: SIGESAC
Jest · Supertest
Used in: GPE
Vitest · Testing Library
Used in: SIGESAC, FCTB
Playwright · Selenium
Used in: SIGESAC, FCTB
SonarQube
Used in: SIGESAC

DevOps and infrastructure

GitHub Actions
Used in: SIGESAC
Jenkins
Used in: SIGESAC
Docker
Used in: SIGESAC, GPE, UniEventos
Prometheus · Grafana
Used in: ShopSystem

Practices

ADR · documentación técnica
Used in: SIGESAC, GPE
Conventional Commits
Used in: SIGESAC
RBAC · auditoría
Used in: SIGESAC, GPE

Open source

My public academic and personal projects live on GitHub. Client work stays private.

View GitHub profile

Let's talk

I'm looking for my first full-stack or backend role. Email is the fastest way to reach me.

nestorfelipe10@gmail.com
Send an emailLinkedInGitHubRequest résumé

I'll email you my résumé as a PDF.

Armenia, Quindío, Colombia