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Renan Leme Menezes

Fullstack Developer + Offensive Security

I build web apps that are secure from day one.

React, Node.js, and TypeScript in production. Pursuing a postgrad in Offensive Cyber Security (FIAP). Itu/SP, Brazil · Remote.

About

I'm a fullstack developer with around 2 years in production. I built a multi-tenant SaaS platform from scratch: billing with idempotent webhooks, retry and reconciliation, contract generation and digital signing, and payment gateway integrations. I like solving the problem end to end, from the database to the deploy.

Along the way, I maintained a corporate ERP in PHP, built real-time vehicle tracking, and spent a year teaching programming — the foundation for how I review code and explain technical decisions to this day. I'm now pursuing a postgrad in Offensive Cyber Security at FIAP, bringing together the two sides that interest me most: building well and building secure.

Featured Projects

AI-Powered Ticket Panel

problem
Support conversations in Chatwoot turned into scattered bug reports, with no structure or priority — manual, slow triage.
solution
A panel embedded in Chatwoot that turns conversations into structured bug tickets via LLM integration: prompt engineering with schema-validated JSON output, anti-hallucination guards, PII removal, and automatic priority classification.
result
AI applied in production with controlled output and PII handling — engineering with validation, not a demo.
  • Next.js 16
  • React 19
  • TypeScript
  • PostgreSQL
  • SSE
  • LLM

Billing & Digital Contract Signing

problem
smartGPS's new multi-tenant SaaS platform needed to bill and formalize contracts without manual intervention — real money, errors aren't an option.
solution
A multi-tenant billing system + contract generation and e-signature: REST/Webhooks integrations with payment gateways, idempotent webhooks, retry with exponential backoff, and reconciliation.
result
Critical financial integration with real resilience — idempotency, retry, and reconciliation in production.
  • Node.js
  • TypeScript
  • PostgreSQL
  • Webhooks
  • REST

Experience

  1. Fullstack Developer · smartGPS

    Feb 2026 – Aug 2026 · Remote

    • New multi-tenant SaaS platform from scratch (React 19 / Next.js 16 / Node.js / TypeScript / PostgreSQL)
    • Complete billing system with idempotent webhooks, retry with exponential backoff, and reconciliation
    • Contract generation and digital signing module, with integration to payment gateways and e-signature APIs
    • Security in production: HMAC session with delegated identity, fail-closed origin trust, secrets isolation, and PII handling
    • Platform deploy in containers (Docker Swarm) with zero-downtime rolling updates and idempotent migrations

  2. Fullstack Developer · Baron Tech

    Sep 2024 – Apr 2025

    • Development and maintenance of modules in a corporate ERP (PHP)
    • 3+ REST integrations in production: financial gateway with idempotency, transactional SMTP with OAuth 2.0 + token refresh, cloud storage with retry and backoff

  3. Software Developer · smartGPS

    Aug 2023 – Aug 2024

    • Real-time vehicle tracking system (Node/React)
    • Integration with location and monitoring APIs; performance and security optimization

  4. Programming Instructor · SuperGeeks

    Aug 2022 – Jul 2023

    • Classes, teaching materials, and class mentoring — a direct foundation for code review and technical communication

Stack & Skills

  • frontend

    • React
    • Next.js
    • TypeScript
    • JavaScript
    • HTML

  • backend

    • Node.js
    • Express
    • PHP
    • REST APIs
    • Webhooks

  • databases

    • PostgreSQL
    • MySQL
    • MongoDB

  • security

    • OAuth 2.0
    • JWT
    • HMAC sessions
    • PII handling
    • Secrets isolation

  • infra & devsecops

    • CI/CD
    • Google Cloud Storage
    • Git

  • domain

    • Billing
    • E-signature
    • Payment gateways
    • Applied AI (LLMs)

Formal coursework (DIO/Alura) — not yet used in production.

  • C# / .NET
  • Python (fundamentals + data analysis)
  • GenAI & Prompt Engineering
  • Offensive security (FIAP postgrad, in progress)

Education & Certifications

Postgraduate — Offensive Cyber Security (Red Team Ops)

in progress · online

FIAP Postech · Jun 2026 – Apr 2027

  • Pentest
  • Red Team Ops
  • OSINT
  • Web Hacking
  • Malware Analysis
  • Python for Red Team
  • Purple Team
  • AI applied to security

Associate Degree in Systems Analysis and Development

Fatec Dom Amaury Castanho · 2021 – 2024

Capstone project: an Augmented Reality app in Unity/C# for visualizing interior design in a real-world environment — public code

Certifications

Courses (DIO / Alura)

  • TypeScript Fullstack Developer track · DIO, 2024 (React + Node + TS + TypeORM + tests)
  • C#/.NET Developer track · DIO, 2025 (OOP, data structures, APIs, .NET)
  • GenAI & Prompt Engineering · DIO, 2026 (Generative AI, LLMs, prompting, Copilot)
  • Python & Data Analysis · DIO, 2026 (Python, data analysis, anomaly detection, SQL/BI)
  • PHP Development Fundamentals · DIO, 2024
  • Web Accessibility · Alura (inclusive front-end, accessible components)

Cybersecurity

  • Santander Cybersecurity Bootcamp · DIO, 2024 (fundamentals, pentest, deep web & anonymity, principles)
  • Santander Acceleration · Cybersecurity & Security in Vibe Coding — DIO, 2026
  • Introduction to Cybersecurity Data Collection & Analysis · DIO, 2026
  • Topics in Social Engineering · DIO, 2026

Backend/Web (Alura)

  • REST with Node.js · Express + MySQL
  • HTTP
  • JWT Authentication with Node/TS

Contact

Open to fullstack and dev+AppSec roles, remote — get in touch.

renanlmenezes2003@gmail.com