CTO & Co-founder at ZapYou · Software Engineer · Application Security
Multi-tenant SaaS platforms and automation. 10+ years shipping — and operating — what I build.
CTO and co-founder of ZapYou. More than ten years writing software, much of it spent on the operational problems inside companies that nobody else wants to take on.
At ZapYou I own the architecture and development of a WhatsApp Business communication platform integrated directly with Meta's Cloud API as a Tech Provider — every customer operates their own WABA, with no reseller layer in between. The day-to-day work is tenant data isolation enforced at the ORM layer, idempotent message delivery against webhooks that arrive out of order, and LGPD resolved in the system design rather than patched on afterwards.
In parallel I work through ARIERRAC INC on custom software and maintain open source projects, among them a scheduling and verification tool for database backups. At IPOG I build the internal systems used by several units across Brazil, and at Espaço Paulista I own the network and the live broadcast infrastructure for events. Very different contexts, but usually the same problem: understand the operation before writing code.
I understand the business problem before choosing the technology. Most of the decisions I make are about what not to build.
I operate what I build. Own servers, Docker, Cloudflare, observability and incident response. That changes how you write code.
Security is not the last step. I run periodic OWASP-referenced audits on the codebases I maintain, and treat threat modeling as part of designing any feature that touches customer data.
| Role | Organization | Period |
|---|---|---|
| CTO & Co-founder | ZapYou | 2023 — present |
| Full Stack Developer | IPOG São Paulo | 2020 — present |
| Founder | ARIERRAC INC | 2019 — present |
| IT Manager | Espaço Paulista de Eventos | 2016 — present |
Full history at kleyson.org.
- Backend — TypeScript · Node.js · Fastify · NestJS · Prisma · Python
- Frontend — Next.js · React · Vue.js · Tailwind CSS
- Data — PostgreSQL · Redis · Qdrant · MongoDB · MySQL
- Infrastructure — Docker · Kubernetes · Terraform · Cloudflare · NGINX · Linux · AWS · GitHub Actions
- Security — OWASP · Threat modeling · Web pentesting · Burp Suite · Nmap · Wireshark · Kali Linux
90 certifications across security, cloud, backend and networking. Most recently TryHackMe Pre Security (2026) and the Linux LPI Essentials track (2025), alongside a Cybersecurity certificate from IPOG (2020).
Open to conversations about multi-tenant architecture, Meta platform integrations, application security and process automation.