---
type: source
tags: [parking, architecture, source]
sources: [parking-system-architecture]
updated: 2026-06-14
---

# Source: Parking Management System — Architecture & Design Notes

A working design reference (not a final spec) recording architectural decisions, the
reasoning behind them, and rejected alternatives for a parking-management system. Several
items are explicitly open. Raw file: `raw/parking-system-architecture.md`.

## Key takeaways

- The system is a **web app on Linux, deployed on-site**. Two forces shape every decision:
  [[offline-first]] operation and the **physical-security reality** of a machine in an exposed booth.
- **Stack** ([[technology-stack]]): [[turborepo]] · [[fastify]] (Node) · [[react-vite-spa]] ·
  [[sqlite]] + [[drizzle-orm]] · [[local-jwt-auth]]. All MIT/Apache/BSD — chosen for **no vendor
  lock / no rug-pull risk** (the reason [[payload-cms]] was rejected).
- **The threat-model reframing** ([[threat-model]]): the primary adversary is the **legitimate
  operator at the booth**, not an outsider stealing the machine. Encryption-at-rest defends the
  wrong threat. The real controls are the [[append-only-event-chain]] (hash-chained,
  [[atecc608]]-signed) plus [[reconciliation]] against an authority the operator can't alter.
- **Devices** go through a [[device-adapter-pattern]] so hardware swaps don't touch business logic.
  Safety principle: [[barrier-not-a-door]] — physical safety lives in the barrier operator firmware.
- **Access control** today is the [[uhppote-controller]] on an isolated VLAN — tamper-*evident*,
  not tamper-*proof*, because its [[uhppote-udp-protocol|UDP protocol]] is unauthenticated. The
  [[esp32-custom-controller]] is documented as the prevention-grade upgrade (challenge–response
  with asymmetric signatures).
- **Readers** split into two populations ([[entry-exit-readers]]): permit holders (best via
  [[wiegand]] into the controller, autonomous) and casual/transient (host-side: [[lpr-camera]],
  QR/ticket). Both can share one relay.
- A reference [[bom|BOM]] lists recommended devices; **6 open decisions** remain
  ([[open-questions]]) that drive procurement.

## Section map

| § | Topic | Wiki pages |
| --- | --- | --- |
| 1 | System context | [[offline-first]], [[threat-model]] |
| 2 | Technology stack | [[technology-stack]], [[fastify]], [[sqlite]], [[drizzle-orm]], [[turborepo]], [[react-vite-spa]], [[local-jwt-auth]], [[payload-cms]] |
| 3 | Data security & threat model | [[threat-model]], [[append-only-event-chain]], [[atecc608]], [[reconciliation]], [[disk-os-hardening]] |
| 4 | SQLite limits | [[sqlite]] |
| 5 | Device architecture | [[device-adapter-pattern]], [[barrier-not-a-door]], [[trust-boundary]] |
| 6 | UHPPOTE access control | [[uhppote-controller]], [[uhppote-udp-protocol]], [[network-isolation]], [[event-log-ingestion]] |
| 7 | Custom ESP32 controller | [[esp32-custom-controller]], [[challenge-response-auth]], [[atecc608]], [[fail-state-safety]] |
| 8 | Entry/exit readers | [[entry-exit-readers]], [[wiegand]], [[lpr-camera]] |
| 9 | Recommended devices (BOM) | [[bom]] |
| 10 | Open decisions / next steps | [[open-questions]] |
| — | Summary of standing decisions | [[standing-decisions]] |