Full-stack developer building secure SaaS platforms, internal systems, and production AI workflows with TypeScript, React, Node.js, and PostgreSQL.

I help businesses replace spreadsheets, disconnected tools, repetitive administration, and fragile automations with reliable systems designed around their actual workflows.

My work focuses on clear domain rules, secure access control, tenant isolation, transactional correctness, deterministic behavior, and maintainable architecture. For AI-enabled systems, models assist with classification, extraction, retrieval, recommendations, and drafting while business rules and approval authority remain under controlled application logic.

• Multi-tenant SaaS platforms
• Client portals and internal operations systems
• Lead capture, quoting, and estimate workflows
• Reporting and decision-support dashboards
• API integrations and workflow automation
• AI-assisted workflows with validation, approval, and audit controls
• Retrieval systems with permission-aware data access
• Evaluation and observability tooling for AI applications

• Frontend: React, Vite, Astro, TypeScript
• Backend: Node.js, TypeScript, Fastify, Express
• Database: PostgreSQL, schema-first design, constraints, transactions
• Architecture: Clean and Hexagonal architecture, domain boundaries
• Security: Tenant scoping, authorization, validation, audit-friendly flows
• AI Applications: Structured outputs, workflow orchestration, retrieval, evaluations, approval controls, and provider isolation
• Secondary: Python/Django and ASP.NET Core/C#
• Deployment: Vercel, Render, Neon, Cloudflare, Docker

Reusable lead capture and estimate engine for service businesses.

Highlights:

• Multi-tenant configuration
• PostgreSQL-backed pricing rules
• Embeddable widget
• Lead capture workflow
• API-driven estimate generation
• Portal foundation for tenants

Tech: TypeScript, PostgreSQL, React, Vite, Express

Private tool for capturing client discovery calls, manual notes, transcript segments, requirements, and structured call history.

Highlights:

• Tenant-scoped call records
• Manual and transcript-based note capture
• Requirement extraction
• Deterministic sequence numbering
• Clean frontend/backend separation

Tech: TypeScript, PostgreSQL, React, Vite, Express

Transactional income and expense tracking system focused on correctness.

Highlights:

• Schema-first financial records
• Database constraints
• Balance calculation logic
• Reporting foundation
• Data integrity rules

Tech: TypeScript, PostgreSQL

• Schema first
• Explicit domain models
• Database constraints over app-only assumptions
• Transactions where correctness matters
• Tenant scoping and authorization by default
• Idempotent operations where useful
• Clear separation between domain, application, infrastructure, and HTTP layers
• Predictable behavior over hidden magic

• Portfolio: https://belovedjohndev.com