Built Systems & Tools

Systems and products built to practice architecture, business rules, and technical decisions in the real world.

01 · 2026 · SaaS Product · Parking Operations

ParkFlow

SaaS for parking operations, with license-plate-driven flow, space control, monthly subscribers, and automations.

STUDY PROTOTYPE · AI-ASSISTED MVP

React TypeScript PostgreSQL Supabase Relational Modeling Plate-driven UX

Context & Business Rules

Built from a real operations problem: license-plate-driven flow, reconciling fractional stay durations, grace periods, and managing rotating and monthly spaces.

Engineering Decisions

Strict relational modeling in PostgreSQL to guarantee integrity and stay history, with explicit separation between fractional pricing rules and the operational interface.

02 · 2026 · Local Tool · On-Disk Courses

Local Player

Local/offline player in Node.js + Express + vanilla JS to organize and watch thousands of on-disk lessons, with no build step, portable progress, fallback transcoding, and local Whisper subtitles.

EVOLVING · LOCAL/OFFLINE PLAYER

Node.js Express Vanilla JS FFmpeg whisper.cpp Zero build step

Architecture Technical Journal

Context & Business Rules

Born from courses scattered across HDDs, SSDs, and USB drives: physical structure as source of truth, per-library cached scan, Range-206 streaming, and atomic progress in .courseplayer files that travel with the disk.

Engineering Decisions

Thin server.js with submodules, atomic writes with fsync + serial queue + dual backup, per-codec fallback with fragmented MP4, and a P0–P3 priority Whisper queue under a heavySlots semaphore.

Editorial standard: Unfinished projects appear as work in progress. Studies appear as studies. I do not use fictional user numbers, invented cases, or results that do not exist.