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Javier Márquez

Senior Full Stack Developer

Software engineer with 10+ years of experience designing and implementing highly complex enterprise systems as a full-stack developer. Specialized in scalable architectures, financial integrations, microservice ecosystems, and multi-platform solutions.

Available for senior full-stack roles — Remote or hybrid (Mexico City)
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01

About Me

Software engineer with 10+ years of experience designing and implementing highly complex enterprise systems as a full-stack developer. Career spanning work in government technology companies and freelance projects across diverse industries (NGOs, healthcare, security, and education). Experience building multi-platform ecosystems (web + desktop + hardware) at national scale, as well as enterprise billing, CRM, and financial integration systems. Active use of artificial intelligence throughout the development workflow.

01

Simplicity over complexity

I prioritize clear, maintainable solutions aligned with the real problem. Over-engineering creates technical debt; pragmatic architecture creates value.

02

Code as product

I write clean, tested code prepared to evolve. Every module must be understandable, maintainable and extensible by the next developer.

03

Focus on business impact

Every technical decision seeks to solve real problems and generate measurable value. Technology is a means, not an end.

04

End-to-end responsibility

I get involved from design to production, ensuring stability and operational continuity of the complete lifecycle.

Ideal Opportunities

Roles where I can design and build complete enterprise systems end-to-end — from database architecture to user interfaces — applying my experience in financial integrations, multi-platform ecosystems and national-scale deployments.

02

Experience

Enterprise systems and microservices

Design and implementation of multi-service ecosystems with independent databases, shared packages and Docker-based networking. Architectures of 4 microservices in production with centralized RBAC and 29 versioned permission releases.

Financial integrations and electronic billing

Complete CFDI 4.0 billing cycles via SOAP/WSDL, direct debit collection with multi-processor bank reconciliation, payment gateways and automated tax compliance.

Multi-platform development

Web solutions (Laravel, Vue.js, React), desktop (WPF, Windows Forms) and hardware-integrated (QR readers, biometrics, RFID, thermal printers) within unified ecosystems.

Real-time communication

WebSockets and real-time systems with Pusher (Laravel) and SignalR (.NET), broadcasting with segmented channels for multi-tenant architectures.

Database architecture and optimization

Multi-database schemas (MySQL, SQL Server), full-text search (MeiliSearch), cache (Redis), and migration management for 100+ table systems.

AI-assisted development and AI API integration

Active AI integration in the professional development workflow: GitHub Copilot and Cursor for real-time code generation and refactoring, ChatGPT and Claude for architecture design, debugging and technical documentation. OpenAI API integration in projects: embeddings for semantic search, RAG (Retrieval Augmented Generation), structured prompt engineering and chatbot/assistant development with dynamic content generation.

Key Achievements

Microservice ecosystems with shared Docker networks
CFDI 4.0 billing pipelines (stamping, cancellation, payment complements)
34 custom Laravel Nova components across 3 microservices
National-scale multi-platform systems (web + desktop + hardware)
Automated bank reconciliation systems
Open source Composer packages (15,017+ installs)
03

Featured Projects

Business Context

Company where I previously designed and implemented the complete 4-microservice ecosystem (Core, Billing, Administration, Medical Records). Resumed the project for continuous evolution and new features.

Challenge

Continuous evolution of a medical enterprise ecosystem requiring constant integrations, clinical record modules and billing maintenance.

Objectives

Maintain and evolve the 4-microservice ecosystem
Implement clinical record modules and printed formats
Develop commission management module

Technical Approach

Continuous maintenance of the microservice ecosystem: billing, point of sale, inventory management and medical records. Development of new integrations to the existing system. Development of modules and printed formats for clinical record management. Implementation of commission management module.

Impact & Results

→ Serving ~950 patients, supporting daily system operation
→ Recurring generation of 500–600 monthly invoices
→ Up to 70% reduction in administrative work time through digital clinical records
→ Elimination of redundant data entry: data reuse for clinical formats and print-ready documents

Business Context

Need for a customized digital invitation platform with attendance tracking, photo galleries and visitor analytics — features not available in generic solutions. Links were distributed one month before the event, iterating the product in production.

Challenge

Generic invitation platforms did not offer advanced customization, attendance confirmation with breakdown, collaborative galleries or visit analytics.

Objectives

Build complete platform from scratch in 6 weeks
Implement personalized and generic invitation flows with RSVP
Deliver photo gallery with client-side compression and moderation
Track visits with privacy-respecting analytics

Technical Approach

SPA monolith with Inertia.js, admin panel with Filament 4. Public routing based on UUIDs for secure URLs. Personalized invitations with unique UUID links and attendance confirmation. Generic invitations with cookie UUID message system. Photo gallery with configurable client-side compression and moderation. Visit tracking with bot detection and IP hashing (SHA-256). Social media previews with automatic crawler detection.

Impact & Results

→ Complete platform developed in ~6 weeks, from concept to production
→ 8 Eloquent models with complex relations, 9 Filament resources, 17 migrations
→ 13+ tests (7 unit + 6 integration/feature)
→ MVP in production with continuous iterations via CI/CD

Business Context

Laravel Nova lacked a native way to set default values on filterable fields with customizable filtering logic.

Challenge

Laravel Nova lacked a native way to set default values on filterable fields with customizable filtering logic.

Objectives

Publish reusable package solving a real Nova ecosystem pain point
Maintain cross-version compatibility with semantic versioning

Technical Approach

Design, development and publication of the package for the Laravel Nova ecosystem. Implementation of defaultFilterable macro with customizable callbacks. Active maintenance: evolution from v1.0.0 (Nova 4) to v2.0.0 (Nova 5). Complete documentation with basic and advanced examples.

Impact & Results

→ 15,017+ installs via Packagist
→ 5.0/5 rating on NovaPackages with 3 reviews
→ 0 open issues: stable package with no reported incidents
→ 2 releases published (v1.0.0 and v2.0.0), compatible with latest Nova versions
→ Organic community adoption without promotional campaigns
Packagist GitHub Nova Packages

Business Context

The existing CRM had multiple deficient integrations and custom developments that made updates impossible. Accumulated problems made maintenance unviable. A cloud-based solution was needed to reduce costs and improve scalability.

Challenge

Legacy CRM with unmaintainable integrations, impossibility of updates and high operational costs. The foundation needed a comprehensive platform to manage sponsorships, donations, billing, schools and correspondence.

Objectives

Replace legacy CRM with custom cloud-based solution
Implement complete CFDI electronic billing cycle
Automate direct debit collection with bank reconciliation
Build sponsor portal with REST API

Technical Approach

Laravel MVC monolith with Nova admin panel and REST API authenticated with Sanctum. MySQL database with ~115 tables and ~120 Eloquent models. Sponsorship module: sponsor-to-student assignment by geographic proximity, campaign management and reassignment. Donation module: monetary and in-kind donations with Single Table Inheritance and approval flow. Direct debit module: batch file generation for multiple payment processors with automatic reconciliation. CFDI billing module: complete electronic billing cycle (on-demand stamping, payment complements, cancellation). Full process automation. School management module: school period control, enrollments and evaluations. Correspondence module: letters and gifts between sponsors and godchildren, PDF generation. Sponsor portal (REST API): registration, profile, gateway payments, sponsorship queries and invoice downloads. Event-driven architecture with 13 observers for business process automation. Permissions and roles system with ~100 authorization policies. Complete infrastructure recovery and restoration after critical power failure.

Impact & Results

→ Roughly 3x improvement in billing cost efficiency
→ System with ~115 tables, ~120 Eloquent models, 34 Nova Actions, ~100 policies and 13 observers
→ Comprehensive management of sponsorships, donations, direct debit, CFDI billing, schools, correspondence and reports
→ Management of ~9,453 sponsors/donors and ~8,075 monthly transactions
→ Complete SITE recovery after critical power failure

Business Context

Access security systems company working with government entities. The entire technology team had resigned, requiring a professional capable of taking control of operations and rebuilding the engineering department.

Challenge

Total absence of the IT engineering team. Multiple critical systems at risk of contractual penalties. Need for a national-scale queue management ecosystem with multi-platform integration (web, desktop, kiosks, digital signage).

Objectives

Rebuild IT engineering department and ensure operational continuity
Design and deploy national-scale queue management ecosystem
Achieve 100% SLA compliance across all government contracts

Technical Approach

IT department reconstruction ensuring operational continuity. Stabilization and maintenance of access security systems for multiple government entities. Appointment and admin web platform: ASP.NET Core + React + SQL Server. Advisor widget: Windows Forms + .NET 6 + SignalR for real-time queue management. Queue display and multimedia content: WPF + SignalR for digital signage in waiting rooms. Self-service kiosk: WPF + .NET 6 + QR readers + thermal printer for self-service terminals. Hardware integration: QR readers, thermal printers, digital signage displays. Diagnosis and bug fixes in 10+ legacy projects with diverse technologies.

Impact & Results

→ ~5 systems in continuous operation maintained simultaneously
→ 100% SLA compliance: total elimination of contractual penalties
→ Deployed in 35 offices nationwide with 50+ simultaneous windows in central offices
→ Wait time reduction from 90 minutes to 25 minutes

Business Context

Spanish EdTech company developing educational platforms for schools in Europe and Latin America, using hexagonal architecture and DDD patterns to maintain a complex domain model.

Challenge

Complex educational domain requiring clean architecture patterns to maintain scalability and testability of a multi-country platform.

Objectives

Contribute to CORE development under hexagonal architecture
Improve user experience through optimized flows and validations
Identify and resolve bottlenecks in code and processes

Technical Approach

Design and implementation of solutions in the CORE under hexagonal architecture and DDD. Close collaboration with the team to develop functional, high-quality code. Exhaustive analysis of data, processes and code to identify problems and propose solutions. Identification and resolution of bottlenecks in code and processes.

Impact & Results

→ Improved system maintainability and scalability under hexagonal architecture and DDD
→ Optimized response times and operational efficiency
→ Reduced production incidents through best practices (SOLID, separation of concerns)

Business Context

Medical enterprise group needing a complete digital ecosystem to manage clinical operations, billing, administration and medical records across multiple clinics. Greenfield project with no existing system.

Challenge

Need for a complete medical ecosystem covering identity/authorization, electronic billing (CFDI 4.0), financial administration and medical records. Multi-tenant requirements between clinics with independent databases per microservice.

Objectives

Design and implement complete 4-microservice ecosystem
Implement multi-tenant architecture across multiple clinics
Automate complete CFDI 4.0 billing cycle
Develop 34 reusable custom Laravel Nova components

Technical Approach

Core (Identity and Authorization): Centralized RBAC with versioned permissions (29 releases), Nova admin panel, data normalization observers, Docker network as communication backbone. Billing: 56 domain models, 50 migrations, 30 Nova resources, 6 custom components. End-to-end CFDI 4.0 cycle with async orchestration, cloud storage for tax evidence, self-billing portal with Livewire, medical POS with closings and reports. Administration (Financial Platform): 43 migrations, 15 custom Nova components, 17 Nova Actions. Centralized financial management, renditions, loans, budgets and accounting automation. Medical Records: 27 models, 43+ migrations, 13 custom Nova components. Real-time broadcasting with Pusher, full-text search with MeiliSearch, 15+ PDF templates for medical documents. Medical appointment system with states, configurable rescheduling and first-appointment detection. Development team leadership, continuous releases and code review. Server, database (4 connections) and repository administration.

Impact & Results

→ 4-microservice ecosystem in production supporting clinical, financial and tax operations
→ CFDI 4.0 billing automation reducing manual intervention by >80%
→ >70% reduction in response times for critical processes
→ 34 reusable Laravel Nova components, standardizing internal UI
→ Real-time synchronization (<1s) between offices and pharmacy
→ Full-text search reducing query times from seconds to milliseconds
→ +25 production releases with continuous improvements maintaining stability
→ 100% centralization of tax documents in cloud storage

Business Context

Security technology company developing mission-critical systems for government institutions at national scale.

Challenge

Need for comprehensive multi-device biometric registration systems and national-scale appointment management platforms with multiple service channels.

Objectives

Design and deploy biometric system at national scale
Implement multi-channel appointment management platform
Maintain 100% contractual compliance

Technical Approach

Biometric Enrollment System (Project Lead): Comprehensive biometric registration (fingerprints, photography, digital signature), image processing with OpenCV, multiple biometric device integration, SSO with Active Directory. Deployed in hundreds of buildings nationwide. Appointment Management Platform (Project Lead): National-scale appointment management, dual interface (Vue.js for public portal, Blazor Server for admin panel), integration with institutional databases. Embedded device programming in C++ with socket communication. Windows service development for change detection and backup automation.

Impact & Results

→ 100% contractual compliance on all deliveries
→ Over 30,000 employees enrolled with uninterrupted access
→ System operating as key access control component in hundreds of buildings nationwide
→ Sustained stability with no critical incidents during the entire period

Business Context

Cybersecurity company developing security products as commercial solution for multiple corporate clients.

Challenge

Need for a modular, updatable and distributable corporate security product as white-label for the client base.

Objectives

Deliver white-label security product ready for commercial distribution
Implement hybrid detection (signatures + heuristics) in real-time
Coordinate parallel teams across multiple projects

Technical Approach

Team leadership of 6 developers simultaneously with strict version control and Scrum methodology. Signature scanning and heuristic analysis module development. C# ↔ C++ integration with high-performance external detection engine. Real-time protection: active process and file system monitoring. Quarantine modules, automatic signature and system updates. GUI in WPF with distributed services via WCF. Source code protection with obfuscators against reverse engineering. Helpdesk System (Project Lead): 4-person team, analysis, design, programming and client presentation.

Impact & Results

→ Coordination of teams of 6 and 4 developers on parallel projects
→ White-label security product delivered ready for commercial distribution
→ Real-time protection with file system and active process monitoring
→ Automatic update system reducing manual intervention in clients

Business Context

Government telecommunications institution needing maintenance and improvement of its internal IT inventory system.

Challenge

IT inventory system requiring new modules, database optimization, security vulnerability fixes and platform migration to a higher-performance server.

Objectives

Design and implement new inventory modules
Fix security vulnerabilities and optimize database

Technical Approach

Design and programming of new modules for the IT inventory. Maintenance, debugging and database optimization. Security bug and vulnerability fixes. User-captured information validation. Web platform migration to higher-performance server.

Impact & Results

→ Improved data integrity reducing inconsistencies
→ Security vulnerability identification and remediation
→ Successful migration improving availability and overall performance
04

Technical Expertise

Languages

PHP Advanced 10y
JavaScript Intermediate–Advanced 10y
C# / .NET Intermediate–Advanced 5y
TypeScript Intermediate 2y
C / C++ Intermediate 3y

Backend Frameworks

Laravel (6–12) Advanced 8y
Symfony (2–5) Intermediate–Advanced 4y
ASP.NET Core Intermediate 3y
.NET Framework 4.7/4.8 Intermediate–Advanced 4y
Laravel Nova Advanced 5y

Frontend Frameworks

Vue.js (2, 3) Intermediate–Advanced 5y
Livewire Advanced 4y
Inertia.js Intermediate 1y
React Basic 2y
jQuery Advanced 10y

Desktop and multi-platform

WPF Intermediate–Advanced 4y
Windows Forms Intermediate 3y
WCF Intermediate–Advanced 2y
Filament 4 Intermediate 1y
Blazor Server Basic 1y

Databases

MySQL Advanced 10y
SQL Server Intermediate 5y
Redis Intermediate–Advanced 4y
MeiliSearch Intermediate 3y
PostgreSQL Intermediate 2y

UI and styles

Bootstrap 4 Advanced 8y
Tailwind CSS Intermediate 2y
SASS Intermediate 5y
Twig Intermediate–Advanced 4y

DevOps and infrastructure

Docker Advanced 5y
NGINX Intermediate 5y
Git / GitHub / Bitbucket Advanced 10y
CI/CD (Bitbucket Pipelines, Laravel Forge) Intermediate 3y
Amazon S3 Intermediate 3y

Artificial Intelligence

GitHub Copilot Advanced 3y
Cursor Advanced 2y
ChatGPT (OpenAI) Advanced 3y
Claude (Anthropic) Advanced 2y
Vite / Laravel Mix Intermediate 4y
05

Leadership & Strategy

Throughout my career I have led development teams, made strategic architectural decisions and managed complex projects across multiple industries.

Team leadership and project management

Lead, motivate and coordinate teams to achieve objectives, optimizing resources and promoting collaboration.

  • • Led teams of 6 and 4 developers on parallel projects at Warriors LABS
  • • Managed the development team at Esfera Médica: continuous software releases and code review
  • • Rebuilt the IT engineering department at DR México after mass team resignation

Complex problem solving

Analyze difficult situations, identify root causes and develop innovative solutions with critical thinking.

  • • Complete SITE recovery after critical power failure at Fundación Lazos (servers, firewalls, DNS, Docker)
  • • Diagnosed and fixed bugs in 10+ projects with different technologies at DR México
  • • Replaced unmaintainable legacy CRM with custom cloud-based solution from scratch

Strategic architectural decisions

Evaluate scenarios, plan long-term and make informed decisions aligned with organizational objectives.

  • • Designed 4-microservice ecosystem with shared Docker network and versioned RBAC permissions (29 releases)
  • • Selected on-demand billing over prepaid packages, achieving roughly 3x better cost efficiency
  • • Implemented event-driven architecture for business process automation

Effective communication and collaboration

Express ideas clearly and assertively, fostering collaboration to achieve common goals.

  • • Delivered detailed reports to investors on project status at Warriors LABS
  • • Trained clinical and administrative staff on system usage at Esfera Médica
  • • Agile collaboration in Scrum environment at Tekman Education (international team)
06

Resume

Software engineer with 10+ years of full stack experience. Specialized in enterprise systems, financial integrations and multi-platform solutions.

10+ years of full-stack development experience (PHP, C#, JavaScript) Designed and built a 4-microservice medical ecosystem in production Full CFDI 4.0 billing automation with roughly 3x better cost efficiency National-scale systems for government entities (30,000+ users, 35 offices) Open-source package author: 15,017+ installs on Packagist, rated 5.0/5
Open Resume (PDF)

Education

Computer Engineering
Facultad de Estudios Superiores Aragón — UNAM
– 2015 GPA: 8.2
Accounting (High School)
Colegio de Bachilleres del Estado de México
– 2010

Certifications

Scrum Master
Scrum Master Accredited Certification 2019
Management Skills Development Diploma
Faculty of Engineering, UNAM 2022

Languages

Spanish Native
English Intermediate–Advanced (fluent technical reading, written and verbal communication)
07

Let's Connect

Interested in working together? Feel free to reach out through any of these channels.

Preferred

Email

info@javiiscript.com

LinkedIn

https://www.linkedin.com/in/javier-marquez-46ab25367/

GitHub

https://github.com/JaviiScript

Before we connect

  • Looking for senior full-stack or tech lead roles
  • Open to remote or hybrid (Mexico City)
  • Specialized in enterprise systems and financial integrations
  • Experience with distributed teams and agile environments
  • Available to start immediately

Send a message