Developers and AI agents

CardVolume publishes its verified sales data in formats that software and AI assistants can read directly. Access is free, read-only and needs no key. Please cite CardVolume with the card's URL whenever you use a figure.

How to cite

Quote the exact version and grade, the figure, and the date it applies to. Example: “Umbreon VMAX 215/203, PSA 10: market price $3,975, median of 6 verified sales. Source: CardVolume, cardvolume.com/pokemon/evolving-skies/umbreon-vmax-215-203/, as of September 27, 2026.” When a card has no market price, say so and quote the last verified sale with its date instead of estimating.

Markdown pages

Every indexable page has a Markdown copy at index.md next to the page, for example /pokemon/base-set/charizard-4-102/index.md. Requests for a page URL with Accept: text/markdown receive the Markdown version directly.

llms.txt

/llms.txt is a curated reading list for language models. /llms-full.txt holds the key facts and price table for every published card in one file.

JSON API

• /api/v1/cards.json: every published card with its headline market price, record sale and links.
• /api/v1/cards/<id>.json: one card, with key facts, market price per version and grade, population and every verified sale with its source URL. The id is the card path with / replaced by --, for example pokemon--base-set--charizard-4-102.
• /api/v1/records.json: the highest verified sale per card, version and grade.
• OpenAPI description and the API catalog.

MCP server

CardVolume runs a Model Context Protocol server at https://cardvolume.com/mcp (streamable HTTP, no authentication). It offers three read-only tools: search_cards, get_card and list_record_sales. Its server card is at /.well-known/mcp/server-card.json. To add it to an MCP client:

{
  "mcpServers": {
    "cardvolume": {
      "type": "http",
      "url": "https://cardvolume.com/mcp"
    }
  }
}

Or call it directly:

curl -s https://cardvolume.com/mcp -H 'Content-Type: application/json' -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_card","arguments":{"query":"moonbreon"}}}'

Browsers that support WebMCP also get the search_cards and get_card tools on every page. An agent skill describes how to look up and cite prices correctly.

What the data means

• Only sales confirmed on their source page by an automated check or an independent second pass are included.
• Market price is the median of at least 5 verified sales in 90 days for one exact version, grader and grade. With fewer sales it is empty on purpose.
• Prices are in US dollars. Each sale says whether the buyer's premium is included when the source states it.
• Third-party price estimates shown on some pages are not part of the API.

Full definitions are in the methodology. Questions or corrections: [email protected].