Looking for a job

Antonio Rosas

@antoniorosas

Backend engineer at Unión Mexicana del Norte building production WhatsApp CRMs and API infrastructure across three organizations.

Mexico

Message

What I'm looking for

I’m seeking full-time remote work, including a full-time work trial period. I’m comfortable with asynchronous, self-directed work and owning features from research and technical planning through implementation, deployment, and monitoring.

At Unión Mexicana del Norte, I designed and built a billing system for the Red de Clínicas Adventistas, unifying front desk, medical care, and billing in one flow with centralized reporting and tax invoicing. I also designed a WhatsApp scheduling CRM on 360dialog that runs across three organizations.

For UMI Evangelismo, I integrated Meta's WhatsApp Cloud API directly, handling webhooks, message delivery, and media for production conversations. I documented design decisions in ADRs, implemented an AES-256-GCM media encryption pipeline, and participated in post-release security audits.

In freelance projects, I replaced manual Excel record-keeping with an organizational management system for 3,000+ churches, and optimized a UMIForms query over 1.45M records from 1–2 minutes to 0.48ms. I’m also a co-founder and CTO of CodeTek, where I’m building products including a loyalty-card and point-of-sale SaaS ecosystem.

Experience

Work history, roles, and key accomplishments

Current

Full-Stack Developer (Backend)

Current

Unión Mexicana Interoceánica

Jan 2026 - Present (9 months)

Developed backend integrations and systems for the Interoceanic Mexican Union, including a WhatsApp CRM using Meta's Cloud API and a hierarchical organizational management system for over 3,000 churches. Owned projects end-to-end from requirements to deployment, including performance optimization and security audits.

NodeJS TypeScript TypeORM React Angular Bootstrap MySQL WhatsApp Cloud API AES 256 GCM JWT ADR

Current

Full-Stack Developer (Backend)

Current

Unión Mexicana del Norte (UMN)

Aug 2025 - Present (1 year 2 months)

Designed and built a billing system and WhatsApp-based scheduling CRM for the Adventist Clinics Network, unifying fragmented processes into a single flow with centralized reporting and tax invoicing. Refactored a Kanban-style pipeline and implemented a multi-tenant architecture with granular roles and permissions.

Laravel Vue3 MySQL REST APIs Multi tenant architecture Webhooks 360Dialog Spatie Packages