How do I get the Cardmarket price of a trading card from a photo?

What the price block holds

• prices.cardmarket: trend, low, avg7 and avg30 in EUR. A missing price is null, never 0.
• prices.cardmarket_foil for Lorcana, Magic and Star Wars: Unlimited, the foil price family with the same fields. The photo does not always tell foil from non-foil, so check the finish fields of your game in the documentation.
• prices.tcgplayer in USD where available.
• cardmarket_id: Cardmarket's product ID (idProduct) of exactly this printing. It is the stable key for Cardmarket imports and your own price lookups later.

From photo to a listing price in Python

This script reuses scan.py from the scanner app tutorial, which runs with the public demo key (10 detections per day, no signup). It takes the trend price, adds a markup and a minimum, and leaves cards without a sure printing to a person. Run python prices.py card.jpg, or python prices.py card.jpg magic.

import sys

from scan import detect  # scan.py from the scanner app tutorial

MARKUP = 1.10    # 10 % above the Cardmarket trend
MINIMUM = 0.25   # never below this, in EUR


def open_printing(card):
    """The card is known but not which printing or rarity: ask, do not guess."""
    return any(card.get(k) for k in ("print_unconfirmed", "rarity_unconfirmed", "version_unconfirmed"))


def listing_price(card):
    if open_printing(card):
        return None
    cm = (card.get("prices") or {}).get("cardmarket") or {}
    base = cm.get("trend") if cm.get("trend") is not None else cm.get("avg30")
    if base is None:
        return None  # no price is null, never 0
    return max(round(base * MARKUP, 2), MINIMUM)


tcg = sys.argv[2] if len(sys.argv) > 2 else "pokemon"
for card in detect(sys.argv[1], tcg)["cards"]:
    price = listing_price(card)
    print(
        card.get("name"),
        "| Cardmarket ID", card.get("cardmarket_id"),
        "|", f"{price:.2f} EUR" if price is not None else "no price, ask the seller",
    )

When there is no price

• print_unconfirmed (Yu-Gi-Oh!, Magic, Star Wars: Unlimited): the card is known, its printing is not. Prices of one card can differ by a factor of 100 between printings, so the API leaves the price empty and lists the printings with their own prices in alternatives.
• rarity_unconfirmed and version_unconfirmed (Yu-Gi-Oh!): the price is the cheapest option, the others are listed. Let your user pick before you sell.
• version_unconfirmed (Star Wars: Unlimited): only the name was read, so even the version of the character may be wrong. Show the alternatives to a person.
• A few cards have no Cardmarket product or no price yet. Then the fields are null.

Which price to use

Trend is a good default for a listing. The 30-day average is calmer for cards that sell rarely, and low is the floor other sellers ask. The prices are for the card, not for its condition: the API does not judge condition, so lower the price yourself for played cards. For a graded slab they remain the price of the raw card.

Frequently asked questions

How fresh are the prices?

They are updated once a day from Cardmarket's price guide, so they move with the market but not within the day.

Can I get the price without a photo?

The Detection API always starts from a photo. If you already know the card, store its cardmarket_id from the first scan and use it as your key from then on.

What does it cost?

One card scan per detected card, the price comes with it. A photo without a card costs nothing. Plans: pricing.