MD Motors — Dealership back-office.

Inventory, sales, and profit for a used-car dealer

A Vermont used-car dealer was running the lot on a Google Sheet plus manual paperwork — inventory, sales, and accountant-side reporting were all hand-touched, and PDF window-stickers were re-keyed by hand whenever new vehicles came in.

Built a Next.js back-office that ingests the dealer's existing Google Sheet (read-only feed) into a Postgres-backed store, layered a PDF parser that extracts vehicles from window-sticker dumps and dedupes against the existing VIN list before insert, and gave the dealer an NHTSA decode button per vehicle so unfamiliar VINs can be enriched on demand.

• Stack
  Next.js 15 App Router + TypeScript + Postgres. Cloudflare Turnstile gates the login route against bot traffic.
• Sheets feed
  Google Sheets API is read-only (`spreadsheets.readonly` scope) — the dealer's sheet keeps being the dealer's sheet; the app reads it and persists into Postgres.
• PDF import
  Window-sticker PDFs parse into vehicle rows; existing VINs in the DB are fetched up-front so the importer can flag duplicates before insert.
• VIN enrichment
  NHTSA decode is a per-row action in the UI — surfaced when the dealer wants to enrich a VIN, not blocked behind a mandatory step.

• PDF → DB
  Window-sticker dumps become inventory rows with VIN dedupe in one upload, instead of hand-keying each vehicle.
• CSV
  Accountant-ready inventory export at `/api/mdmotors/inventory/csv` — `Content-Disposition: attachment`, daily-usable.
• Sheet → DB
  Existing dealer sheet remains the input; the app never writes back, so the dealer's workflow is preserved.

• 1Add a profit column to the accountant CSV by reusing `deriveProfit` from the inventory card so the dashboard tile and the export agree.
• 2Wire automated NHTSA decode on PDF import so a window-sticker upload finishes fully enriched without a per-row button click.
• 3Bidirectional Sheets sync so updates from the app surface back into the dealer's spreadsheet without breaking the read-only-feed posture.