# 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.