Fixed-price items settled in USDC on Solana. No account, no email,
no identity capture anywhere in this flow — the buyer is a Solana address,
nothing more. Your order state lives in this browser only; nothing is sent to us
but the payment itself.
Solana USDC only. Send on the Solana network, with the
pinned USDC token contract shown below. Any other chain or token contract
results in a lost transfer we cannot recover. If withdrawing from an exchange,
withdraw as USDC (Solana), not USDC on Ethereum/Polygon/etc.
1. Pick a product
Add ?sku=<id> to the URL to preselect one.
2. Send the exact amount
The unique amount below is your order identifier on-chain: it is your
product's list price plus a random 2-digit cent suffix. Send exactly that amount
to the treasury address and this page confirms automatically. The memo is
optional convenience for wallet apps — hand-sent transfers from exchanges cannot
carry one, and the amount alone is enough.
Underpayment — this page reports "underpaid by X" and does not confirm.
Top up the difference with the same 10-second window still open, or start a new
order and send the full amount again.
Overpayment — confirmed as paid; the difference is treated as a tip
(or refunded on request to graylingops@proton.me).
Wrong token — only transfers of the pinned USDC contract are matched.
Any other SPL token sent to the treasury is invisible to checkout and needs
manual reconciliation; do not send anything but the pinned mint.
Wrong network / exchange withdrawal errors — Solana USDC only. No
other chain, no other contract address. See the warning above.
Timeout — order intents expire after 30 minutes; generate a new one
and you get a fresh amount. A late payment against an expired amount still
confirms on-chain and is still honored against the product.
Duplicate or spoofed memo — the memo is never trusted for matching
(anyone can attach any memo). The unique amount is the order identifier, so memo
spoofing is inert.
RPC flakiness — the page polls public Solana RPC endpoints with a
bounded-retry fallback, mirroring our own wallet tooling. A missed poll just
delays confirmation by one 10-second cycle; payments are never lost by it.