Methodology

How we collect and verify the data.

Every figure on this site comes from a third-party source we link to. We do not generate prices, set them, or modify them — we aggregate, average, and present.

Card metadata

• Pokemon TCG: Card lists, illustrators, and rarity codes are sourced from the public pokemontcg.io v2 API and cross-referenced with the official Pokemon-Card.com site. Card images are loaded directly from the official Pokemon TCG image CDN.
• One Piece Card Game: Both Japanese and English card data come from onepiece-cardgame.com (operated by Bandai). Card images are loaded directly from the official server.
• Dragon Ball Fusion World: Card data and images come from dbs-cardgame.com/fw/ (operated by Bandai).

Marketplace prices

No marketplace prices are published at the time of writing. The eBay Browse API integration is built but has never run, because we do not yet hold eBay production credentials. When it goes live it will work as described below, refreshed weekly.

• PSA 10 / PSA 9 / raw (USD): the lowest current Buy It Now price, including shipping to the United States. We read up to 50 active listings per card and sort them into PSA 10, PSA 9 and ungraded based on the listing title. Listings graded by other companies (BGS, CGC, SGC and similar) are excluded from the ungraded figure so the comparison stays honest.
• Graded premium: the ratio between the cheapest PSA 10 and the cheapest ungraded copy, shown where both exist.

These are asking prices on active listings, not sold prices. eBay's sold-price data is only available through its Marketplace Insights API, which is a limited release restricted to large partners, so we do not use it and do not claim to. Cards with no usable listings show no price section at all rather than an empty placeholder.

PSA Population

We do not currently publish PSA Population figures. PSA has no public API for population data, and we would rather show nothing than show numbers we cannot stand behind. If we add this later it will be stated here, with the source named.

Mercari

We do not currently publish Mercari prices. Mercari has no public developer API, and we are not willing to scrape a marketplace that has not agreed to it.

What we do not do

• We do not buy or sell cards on this site (yet — that's a Phase 2 plan, separate from the editorial layer).
• We do not accept paid listings or sponsored card features.
• We do not manually adjust prices in either direction.

Refresh cadence

All marketplace and PSA data is refreshed once per week (Monday 03:00 JST). Card metadata is refreshed when a new set is released. The "Last updated" timestamp on each card page reflects the marketplace data refresh, not the metadata.

Known limitations

• eBay sold sample sizes can be small for niche cards. We display sample size next to every average.
• Mercari listing prices are asking prices, not transaction prices. Treat them as a ceiling for raw cards.
• Currency conversion between JPY and USD uses the most recent FX rate at refresh time, not the per-transaction rate.
• We use English card names and translations from the official English releases where available. For Japan-only cards, names use the Japanese print's English equivalent or a romaji approximation.