Joey Hershkop

Selected Work & Case Studies

A selection of production systems, open-source data pipelines, and full-stack software architecture.

Parkking — Toronto Street Parking Intelligence Platform

An end-to-end geospatial system turning 76,849 rows of unstructured Toronto parking bylaws into 21,433 geocoded curb segments with instant offline verdicts across mobile and web:

  • Spatial ETL & NLP Pipeline (parkking-pipeline): Parses freeform legal text for temporal rules and geographic spans, resolves street intersections via Toronto Centreline graph search, and projects spans onto physical road edges using Shapely.
  • Native iOS Client (parkking-ios): Zero-dependency, offline-first mobile app featuring an instant curb bylaw evaluation engine and 60/120 fps viewport polyline batching.
  • Interactive Web App (parkking-web): Mobile-first browser map for instant parking inspection, time scrubbing, and address lookup.
  • Python
  • GeoPandas & Shapely
  • SwiftUI
  • MapKit
  • TypeScript
  • React & MapLibre
  • Spatial ETL

B2B SaaS Stripe Billing & Ingestion Engine

Owned end-to-end subscription billing for a live B2B SaaS platform: raw HTTP body preservation middleware for HMAC signature verification, idempotent webhook processing to prevent replay attacks, and PostgreSQL state mirroring.

  • PHP
  • PostgreSQL
  • Stripe API
  • Webhooks
  • Security
  • React

Reggeee — Greenfield Family Activity Marketplace

Architected a two-sided marketplace from scratch: designed the PostgreSQL schema modeling non-traditional multi-adult families (divorced co-parents, guardians), built Argon2id auth with anti-enumeration protection, Redis session state, and a typed React 19 frontend.

  • React 19
  • TypeScript
  • Slim 4
  • PostgreSQL
  • Redis
  • Argon2id

Event-Driven Realtime Pipeline

Engineered an event-driven pub/sub synchronization bridge using Ably that connects backend webhook mutations to frontend React Query state within milliseconds via automated query invalidation.

  • Ably
  • Pub/Sub
  • TanStack Query
  • TypeScript
  • PHP

Auditable Documents Platform & In-Browser Viewer

Built an end-to-end document sharing and review platform for collaborative B2B organization views. Implemented in-browser previews across PDF, image, and DOCX formats, append-only sharing audit ledgers, file conflict resolution flows, and Playwright e2e suites.

  • React
  • TypeScript
  • PostgreSQL
  • DOCX / PDF Preview
  • Playwright

HoverBot — Vision-Based Navigation System

Authored a multithreaded computer-vision navigation pipeline in Python using OpenCV and NumPy, sustaining 30 fps with ≤ 100 ms image-to-actuation latency and ± 3 cm mean arrival error across 30 physical waypoints.

  • Python
  • OpenCV
  • NumPy
  • Threading
  • Robotics