Full-Stack Engineer · SaaS Builder · AI Automation · Solidity/EVM Security Researcher
I build systems that make or protect money — SaaS products, AI agents, internal tools and smart contract security workflows.
I'm a developer and entrepreneur from Paranavaí, Brazil focused on building SaaS products, AI automations, internal tools and Web3 security tooling.
I work across the full stack: frontend, backend, auth, payments, APIs, dashboards, automation workflows, deployment and agent-based systems. Before software, I co-founded and operated a FTTH internet provider — an experience that gave me a strong operations, finance and business execution mindset.
On the security side, I research Solidity/EVM smart contracts, write Foundry PoCs, validate exploit paths and focus on practical vulnerabilities with measurable impact.
Currently open to remote contract work worldwide, especially for startups and businesses that need speed, ownership and practical execution.
| Area | What I do |
|---|---|
| SaaS & Web Apps | Full-stack products with auth, payments, dashboards, analytics and deployment |
| AI Agents & Automation | LLM-powered workflows, internal agents, WhatsApp automation and business pipelines |
| Internal Tools | Dashboards, back-office flows and operational systems for teams |
| Business Systems | Order management, financial tools, ERP-style platforms and integrations |
| Smart Contract Security | Solidity/EVM review, Foundry PoCs, exploit validation and audit tooling |
I focus on real, reproducible vulnerabilities — not theoretical reports.
- Solidity / EVM smart contract security
- Foundry-based exploit PoCs and fork testing
- Slither and Echidna-assisted review workflows
- DeFi protocol analysis: accounting, access control, liquidity, vaults, oracles and upgradeability
- Completed Damn Vulnerable DeFi 18/18 with writeups
- Audit/contest experience across platforms like Sherlock, Cantina, CodeHawks and Immunefi
- Previous audit work includes protocols such as Kleidi, Morpho, Polymarket, Lombard, Scroll, Pinto and Fira
Frontend
Backend & Infra
AI & Automation
Web3 Security
💡 A mix of public showcases, private production systems, audit work and product experiments.
🔹 Vultrix — Complete management system for 3D printing businesses. Built with TypeScript + Supabase.
🔹 AI agents & automation systems — Internal workflows, bots and integrations for real operational use cases.
🔹 Order Management System — Integration with Mercado Livre for order processing and fulfillment automation.
🔹 Financial Dashboard — Business analytics and financial control platform with real-time data.
🔹 Smart Contract Security Lab — Solidity/EVM research, Foundry PoCs, audit notes and vulnerability writeups.
🔨 Available for remote contract work worldwide.
Portfolio: je4ndev.com · GitHub: JE4NVRG · Focus: SaaS, AI automation, internal tools and smart contract security