Martin Castellanos Director of Automation & software developer

Client project · In production

Loan Collections Platform

A web system that runs the daily collections work of a lending business: loans, installments, payments and reports in one place, on desktop, tablet and phone.

• Installment schedules with partial payments, automatic carry-over and refinancing
• Collections dashboard for overdue, due-today and due-tomorrow payments, with one-click actions
• Role-based access (16 permissions, 3 roles) and an audit log of every change
• Personal data encrypted at rest (AES-256-GCM) while staying searchable

Stack: Next.js, Bun, Prisma, PostgreSQL, Auth.js, Redis, Docker

Product · SaaS + self-hosted edition

MedicApp HN & ClinicLite

Appointment and patient-record software for clinics and private practices in Honduras, in two editions: a multi-clinic SaaS and ClinicLite, a lightweight self-hosted version for a single doctor.

• Patients with Honduran DNI validation, appointments, consultations and file attachments
• Demographic and clinical data stored separately, with isolation between clinics
• 50+ API endpoints documented with OpenAPI 3; Spanish and English interface

Stack: React, TypeScript, Node.js, PostgreSQL, Redis, Docker

Product · Production-ready

DayDeck

An appointment platform for booking-based businesses such as clinics, salons, gyms and consultants, with settings for each industry.

• Organizations with multiple providers and staff
• Automatic email confirmations and reminders through background job queues
• Subscription plans and payments with Stripe and N1co, plus a revenue dashboard

Stack: Node.js, Express, TypeScript, PostgreSQL, Redis/BullMQ, React, GitHub Actions

Personal project · Early stage

FluxStock

An event-driven inventory platform for companies that track stock across several warehouses.

• Data isolation between companies enforced by PostgreSQL row-level security
• Append-only stock ledger: movement history cannot be edited or deleted
• Redis locks and idempotency so duplicate barcode scans never double-count

Stack: Next.js, TypeScript, Drizzle, PostgreSQL, Redis, RabbitMQ, n8n

Work experience + personal R&D

Prepress Automation & SimpleRIP

Tools for print production: automating repetitive Adobe Illustrator prep work, and a raster image processor for screen printing.

• Adobe Illustrator automation suite for proof sheets and production checklists, used on production workstations
• SimpleRIP turns PDF/EPS artwork into halftone separations with set LPI, angle and DPI, for CMYK and spot colors

Stack: Adobe ExtendScript, AutoHotkey, Python, Ghostscript

Hackathon · CubePath 2026

SyntaxSurge

An arcade-style English practice game for Spanish speakers. An LLM generates the questions, and a boss round targets each player’s past mistakes.

Stack: Next.js, Bun, Prisma, PostgreSQL, Redis, Groq