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Juan Merma

@juanmerma

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Senior full-stack engineer at ZentryxApp building a production SaaS ERP and AI legal assistant.

Peru

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At ZentryxApp, I’m the founder and lead engineer of a multi-tenant SaaS ERP in production with paying customers. I built its business systems across NestJS modules and a web and Expo mobile app, including SUNAT e-invoicing, accounting, inventory, POS, and Stripe billing.

I also built an AI legal assistant that retrieves information from Peruvian legal codes and case law, detects amended laws, and routes requests across LLM providers. My other work includes OCR and LLM invoice extraction, price-intelligence and sports analytics projects, and Python audio ML services; I bring these systems to production with automated tests and CI.

Experience

Work history, roles, and key accomplishments

Current

Founder & Lead Engineer

Current

ZentryxApp

Jan 2024 - Present (2 years 9 months)

Founded and led a multi-tenant SaaS ERP in production with paying customers, including SUNAT e-invoicing, accounting, inventory, POS, and Stripe billing. Built an AI legal assistant with RAG over Peruvian legal codes and an OCR-LLM pipeline for supplier invoices.

NestJS TypeScript PostgreSQL Stripe SUNAT E Invoicing UBL 2.1 XML LLM RAG Claude OpenRouter GROQ OCR Docker Railway Expo React Native

Current

General Manager & Systems Lead

Current

Tecnología Informática EIRL

Jan 2020 - Present (6 years 9 months)

Run the family IT retail and services company, overseeing internal systems, network and CCTV projects, and client delivery. Previously worked part-time as a systems analyst from 2009 to 2020, providing hardware/software support, websites, e-invoicing systems, and ERPs.

IT Management Systems Analysis Networking CCTV e invoicing ERP Hardware Support Software support

Software Developer

Egatur · LFA Sports · Honda Motos

Jan 2016 - Dec 2020 (4 years 11 months)

Built business systems for local companies using C#/.NET and ASP.NET on SQL Server, including data modeling, transactional workflows, and reporting. Developed multi-branch desktop ERPs with over 100 WinForms screens, plus Java services and freelance systems for clients across Peru.