The Binder. tracks your Pokemon TCG portfolio against real market data. Here's
where every number on this site comes from, how often it refreshes, and what's
still a work in progress.
Where prices come from
Raw cards (ungraded)
TCGPLAYER
Every raw card pulls its market price from TCGPlayer's public search API
— the same market price that shows on tcgplayer.com. For Pokemon TCG
cards we use the holofoil market value when a holo exists,
otherwise the normal market price. When TCGPlayer is missing a
card entirely (mostly niche JP promos) we fall back to the Pokemon TCG
API's cached TCGPlayer snapshot.
Graded cards (PSA / BGS / CGC / SGC / TAG / ACE)
EBAY
Graded prices come from eBay's sold-listings data via the Finding API.
We query the last 20 sold items matching the exact
card + grade + company and average them — so a PSA 10 Base Set Charizard
reflects what Charizards in that grade have actually sold for recently,
not an asking price. When sold data isn't available (brand-new cards,
obscure grades) we fall back to eBay's Browse API active listings as a
rough asking-price indicator.
Sealed products (boosters, ETBs, collections)
TCGPLAYER
PRICECHARTING
Sealed products price against TCGPlayer first, with PriceCharting as a
fallback for out-of-print sets TCGPlayer no longer carries.
PriceCharting aggregates eBay sold data itself, so the chain terminates
at real market transactions either way.
Japanese cards
TCGPLAYER
TCGDEX
JP card data (names, sets, images) comes from TCGdex, which maintains the
most complete Japanese catalog. Prices follow the same TCGPlayer-first
logic as EN cards — merged onto the TCGdex record by name + number. Some
JP-exclusive sets (World Championships promos, trophy cards, unreleased
expansions) don't have reliable market data anywhere; those show an
estimated or "unpriced" value until a better source exists.
How often prices refresh
Every page load triggers a background refresh for the
Card of the Day and anything visible above the fold. The "refresh
all prices" button in the top-right of the header scans your
entire collection + watchlist and pulls fresh data for each item.
Signed-in users also get a daily auto-refresh
that runs once every 24 hours in the background so your numbers stay
current without manual work.
Market Trends — work in progress
The Market Trends tab is currently a placeholder. Eventually it'll
aggregate week-over-week movement across the sets and cards you care
about — gainers, losers, new chase cards emerging, sealed product
delta. The full dashboard design lives in our git history and is
queued to restore once the daily price-history backfill is wired up.
No numbers are being computed yet; treat any chart
in that tab as a mockup until this section goes away.
How your data is stored
Guest-mode data lives only in your browser's localStorage. Signed-in
data syncs to Supabase (Postgres) with row-level security —
every table is scoped by auth.uid() = user_id, so no
user can read or write another user's data, even via the raw REST
endpoint. The anonymous/publishable key shipped in our client code
is safe by design: it can only do what the security policies allow.
You can export or delete everything at any time from the Account
section of these settings.
Attribution
Card metadata:
pokemontcg.io ·
JP catalog:
TCGdex ·
Prices:
TCGPlayer,
PriceCharting,
eBay ·
Community:
Reddit
The Binder. is not affiliated with The Pokemon Company, Nintendo, or any
trading-card-game company. All card images and trademarks are property of
their respective owners.