# ngc-priceguide — NGC US Coin Price Guide

Retail guide values (USD) per grade for every US coin issue NGC lists; 198 series pages.

- **Engine**: `api` (static HTML + public categories JSON), Firecrawl fallback. 4 s politeness, weekly. Legal note in meta (NGC ToS automated-access clause) — review before production.
- **Flow**: `/coin-explorer/data/categories/` → `/price-guide/united-states/<category-seo>/<SubcategoryID>/` (cursor `index` over the subcategory list).
- **Records**: `catalog_item` per coin (`identifiers.ngc_coin_id`, year, mint mark, variety, designation) + `price_observation` `guide_value` per grade (`grader ngc`, grade token `MS65`, `MS65+`, `PF63`, `MS66★`, `XF+`, `PrAg`) dated with the row's own "Updated" date.
- **Config**: `subcategoriesPerRun`, `onlySubcategories`.
- **Not fetched**: world price guide (Cloudflare challenge), price history JSON, census, cert lookup.