A stablecoin card transaction is authorized in seconds, cleared when the merchant's bank submits the final amount, and settled when the issuer pays the card network, the same three steps as any card purchase. What changes is how the issuer funds that payment: in fiat on bank hours, or in a stablecoin that can move on weekends.
What happens between the tap and the merchant payout?
Authorization asks one question, "can this card pay?", and the answer comes back through the merchant's bank and the card network from the issuer in about two seconds. No money moves yet. The issuer has only agreed to pay later.
Clearing comes next: the merchant's bank submits the day's purchases to the network, which nets them into what each bank owes. Settlement turns that list into money: issuers pay the network, and the network pays the merchants' banks.
The four steps of a card purchase, as an issuer describes them on its public site (Rain, read on November 1, 2026).
Step | When | Who acts | Where the money is |
Authorization | Seconds, at checkout | Merchant's bank, network, issuer | Nothing moves. The issuer checks spending power and fraud signals |
Clearing | End of the day, in a batch | Merchant's bank, network | Nothing moves. The network nets all purchases into amounts owed |
Settlement | Bank days for fiat; any day where the network accepts a stablecoin | Issuer pays the network, network pays the merchant's bank | Funds move in netted batches |
Merchant payout | The merchant's bank schedule | Acquirer (the merchant's bank or processor) | Merchant receives local currency, less its fees |
The amount authorized and the amount cleared can differ. A restaurant tip or a hotel's final bill raises the cleared amount, and the issuer adjusts the hold to match. A refund comes back as a network credit, and the program credits the cardholder under its own terms.
Lumx is not in this path. It does not issue cards, route authorizations or settle with Visa or Mastercard. It comes in before the tap, when a local-currency deposit becomes the stablecoin balance the card spends from, and after settlement, when the cardholder cashes out to a bank. New to the term? See what a stablecoin is.
Where the stablecoin turns into fiat
There are two settlement models, and a cardholder cannot tell them apart. In the first, the issuer sells stablecoin for fiat through a liquidity partner and pays the network over bank rails. In the second, the issuer pays the network in a stablecoin.
Rain says the earliest stablecoin cards sold the user's stablecoin for dollars and settled "the old-fashioned way", so the issuer still prefunded a bank account and waited for banking hours.
Two ways an issuer can fund settlement.
Convert, then settle in fiat | Settle with the network in a stablecoin | |
What the issuer pays the network | Fiat, over bank rails | A regulated stablecoin, on a blockchain the network supports |
When it can pay | Bank days. A Friday evening purchase waits for Monday or Tuesday | Any day, where the network allows it |
Capital tied up | Prefunding for the whole lag | Less, because the lag shrinks |
What the merchant sees | Local currency | Local currency |
The prefunding cost is the reason the second model exists. Rain's illustration: a program whose customers spend $1M a day, heading into a holiday weekend, needs about $4M sitting in a bank account by Friday night, because settlement over ACH and Fedwire does not run on weekends. That is Rain's example, not a measured figure.
The issuer's pick is a treasury decision the cardholder never sees. Lumx's part is the balance behind the card: a custodial wallet holding USDC (how it works) on Ethereum, Polygon or Base (or USDT on Ethereum, Polygon or Tron), funded from a local-currency deposit.
What Visa and Mastercard changed in 2026
Both networks now let issuers and acquirers settle with them in regulated stablecoins. Issuer to network and acquirer to network changed; the cardholder's purchase and the merchant's local-currency payout did not.
Network stablecoin settlement, from Visa's releases of December 16, 2025 and April 29, 2026 and Cointelegraph's report of Mastercard's June 3, 2026 announcement.
Visa | Mastercard | |
Stablecoins | USDC at the US launch | USDC, PYUSD, USDG, USDP, RLUSD, SoFiUSD |
Blockchains | Nine after April: Avalanche, Ethereum, Solana, Stellar, Arc, Base, Canton, Polygon, Tempo | Including Arbitrum, Base, Canton, Ethereum, Polygon, Solana, Tempo, XRPL, as reported by Cointelegraph |
Timing | Seven-day settlement windows in the US | Intraday, weekend and holiday settlement |
Named banks and partners | Cross River Bank and Lead Bank, settling over Solana | ARQ (formerly DolarApp), CBW Bank, Cross River, Lead Bank, Nuvei, in the US and Latin America |
Scale stated | $3.5B annualized run rate as of November 30, 2025, and $7B in April 2026, up 50% in a quarter | None in the report read |
Fee for the option | Not stated | Not stated |
Visa's December release frames the change as seven-day settlement "without any change to the consumer card experience", against "the traditional five-business-day window". For the Mastercard news as it landed, see Mastercard settling card transactions in stablecoins.
Network settlement does not touch local rails. A Pix (Brazil's instant payment system, run by the Central Bank) or SPEI (Mexico's interbank transfer system, run by Banxico) deposit still moves on its own schedule. Lumx does not settle with either network, and Rain, an example of a card issuer in a stack like this, is not a Lumx partner.
What does a stablecoin card transaction cost, and who pays?
The merchant pays the interchange side. The cardholder, or the program, pays for conversion and for the legs in and out of the card.
The fee stack of a stablecoin card purchase.
Layer | Who pays | Size | Source |
Interchange, paid to the issuer | Merchant | US debit, covered issuers: capped at $0.21 plus 0.05% of the value, plus a $0.01 fraud adjustment. Exempt cards: averages of 1.30% to 1.46% of value in 2024 on Mastercard and Visa | Federal Reserve, Regulation II |
Network and processor share | Merchant | Rain puts the merchant's all-in cost at about 2% to 3% in the US, split among the network, the merchant's processor and the issuer | Rain, public site |
Issuer or program fee | Program, sometimes passed on | Set by contract with the issuer. No public figure | Your issuer |
Settlement funding | Issuer | Prefunding capital for the settlement lag. No fee for stablecoin settlement is stated by Visa or Mastercard | Visa and Mastercard announcements |
Conversion | Cardholder or program | The spread when local currency becomes stablecoin, and when stablecoin becomes spendable dollars | The quote at each leg |
Take a $50 purchase. At a covered US debit issuer the cap is $0.245 with the fraud adjustment, 0.49% at most. At the 2024 Visa average for exempt cards, 1.46% of $50 is $0.73: three times the interchange for the same stablecoin behind it.
Stablecoin settlement attacks the funding cost, not the interchange, and none of the announcements says the merchant's price changes.
Lumx sets none of these card layers. It prices the legs around the card: "monthly platform fee plus usage-based per-transaction fees, transparent FX on locked quotes, no pre-funding; no published plans". No pre-funding means the customer does not park capital in settlement accounts before a transaction, because conversion and settlement happen when it starts. The top-up runs through an autoconversion rule, which always converts at the market rate and takes no locked quote, so the cardholder gets no up-front quote on that leg. A partner fee in basis points or a flat amount is applied by your platform on top. The cash-out is a standalone off-ramp transaction, and only there can the quote be locked: a floating rate carries no fee, a 30-second lock carries no fee, and longer locks (one or five minutes) include a fee that covers volatility. The quote returns a base amount and a final amount, so the cost of the cash-out is visible before the cardholder confirms. How stablecoin payout pricing works covers the model in full.
How the balance is checked and held at authorization
The authorization step reads one number: spending power. For a stablecoin card, that number lives in a custodial ledger or behind a wallet approval. What Rain calls real-time funding is the second kind: the user connects a wallet and approves how much the card can spend, each purchase is authorized against the wallet balance, and only the amount needed is committed to a collateral contract at authorization, where it stays until it is liquidated to repay Rain's extension of credit to the user. The rest stays in the wallet, and the approval can be revoked.
Between authorization and settlement part of the balance is committed, so the withdrawable amount is smaller than the balance.
I recommend that a card app show three numbers and never blend them: the wallet balance, the limit the cardholder approved, and the amount held for purchases that are authorized but not settled. I would cap cash-out at the wallet balance minus those holds, because the network settles on its own schedule and a withdrawal that ignores open authorizations leaves the program covering a purchase nobody funded.
On the Lumx side, every customer gets a wallet on each supported blockchain, provisioned with the customer, and webhooks tell the app when the balance moves: onramp.success when a deposit lands, offramp.success when a cash-out leaves, transfer.success for wallet-to-wallet moves. The withdrawable cap is set by your app from the holds it tracks; Lumx returns the wallet balance and fires offramp.success when a cash-out leaves.
How the local-currency legs connect to card settlement
Card settlement runs between the issuer and the network. The cardholder's money reaches the wallet and leaves it on local rails, on a different schedule.
Top-up and cash-out rails for a card balance, from the Lumx docs read on November 1, 2026.
Currency | Rail | Settlement | Cut-off | Page |
BRL | Pix | Instant, 24/7/365 | None | |
MXN | SPEI | Instant, 24/7/365 | None | |
USD | ACH | 1 to 2 business days (a business-day rail) | 2:00 PM ET | |
USD | FEDWIRE | Same business day, typically within hours (a business-day rail) | 3:00 PM ET | |
COP | Collection by Bre-B and PSE; payout by Bre-B and ACH Colombia | Bre-B is instant, like Pix; no ACH Colombia time published | None published |
The USD rows follow bank hours, unlike Pix and SPEI. Bre-B (Colombia's instant payment system) payouts are capped at 1,000 UVB per transaction; ACH Colombia has no per-payment cap.
Lumx is stablecoin payments infrastructure for businesses that move money between Latin America and the rest of the world: one API to collect, hold, convert, and pay out in BRL, MXN, COP, USD, EUR, and GBP or in USDC and USDT, over local rails such as PIX, SPEI, PSE, Bre-B, ACH, FEDWIRE, SEPA, and Faster Payments, with SWIFT and on-behalf-of payments and collections (POBO and COBO) in USD, EUR, and GBP, plus named virtual accounts, custodial wallets, and KYB/KYC built in.
Lumx already carries stablecoin card programs for clients, with the cardholder topping up in local currency and cashing out to a bank account. The top-up is a deposit into a named virtual account (a local account number issued in the cardholder's own name). An autoconversion rule turns each deposit into USDC or USDT in the cardholder's wallet, and the card spends from that balance. The cash-out is a stablecoin payout from the same wallet to a bank account the cardholder registered, started by your platform through the API. The legs are the stablecoin on-ramp and the stablecoin off-ramp, and the guide to funding a stablecoin card.
Each cardholder is a customer who completes KYC (know your customer, the verification of an individual) before the account goes live, because Lumx needs to see every payer and payee, and a structure that moves money for people it has not onboarded needs written compliance approval. For the issuer side of this stack, see Lumx vs Rain and what stablecoin card issuing is.
When a stablecoin card is the wrong tool
A card is the wrong tool when the person you are paying does not need to spend at merchants. A contractor abroad who wants money in a bank account is better served by a local payout over Pix or SPEI than by a card that has to be funded and cashed out again. The comparison is in stablecoin card vs local payout.
It is also the wrong tool when you hoped network settlement would lower what merchants pay. It lowers the issuer's funding cost, and whether any of that reaches the cardholder is the issuer's pricing decision. And a card that spends from a pooled balance, with deposits you cannot tie to a named payer, runs against Lumx's nested-payments rule, which requires written compliance approval for structures that move money for parties Lumx has not onboarded.
Methodology and sources
Sources read on November 1, 2026. Mastercard's newsroom blocks automated readers, so its announcement is read through Cointelegraph. EUR-Lex blocks them too, so no European interchange figure appears.
Visa, Visa launches stablecoin settlement in the United States, December 16, 2025
Visa, Visa accelerates stablecoin momentum: adding five blockchains for settlement, April 29, 2026
Cointelegraph, Mastercard expands support to USDC, PYUSD, RLUSD stablecoin settlement, June 3, 2026
Federal Reserve Board, Regulation II average interchange fee by network, 2024 data
Rain, "The anatomy of a stablecoin card swipe" and "Introducing real-time funding", both read on its public site on November 1, 2026 and both issuer statements, not independent measurements
Lumx docs: Payment rail cut-off times, Wallets, Exchange rates, Partner fees, Webhooks
Verified on November 1, 2026. Operational context, not legal, tax, or investment advice.
Cover photo: Ammar Andiko on Unsplash.
How do stablecoin card transactions settle?
They settle the way any card transaction does: the issuer approves in seconds, the merchant's bank submits the final amount at clearing, and the issuer pays the network at settlement. The stablecoin matters at two points, the balance checked at authorization and, where the network allows it, the currency the issuer pays at settlement. Lumx does not issue cards or settle with the networks; it turns a local-currency deposit into the stablecoin balance a card spends from and sends the cash-out to a bank account.
What happens when the final amount differs from the authorization?
The cleared amount replaces the authorized one, and the issuer adjusts the hold: a higher bill needs spending power to cover the increase, and a lower one releases the difference. A refund returns through the network as a credit. On a Lumx wallet, your app sets the withdrawable cap from the holds it tracks, and Lumx returns the wallet balance and fires offramp.success when a cash-out leaves.
Who pays for a stablecoin card transaction?
The merchant pays interchange to the issuer, along with network and processor fees. The cardholder or the program pays the issuer's program fee and the conversion at each leg. On the Lumx legs, pricing is a monthly platform fee plus usage-based per-transaction fees, with transparent FX on locked quotes and no pre-funding. The top-up converts at the market rate, with your platform's partner fee on top, and the cash-out quote shows its cost before the cardholder confirms.
Does stablecoin settlement make card transactions cheaper?
It reduces the capital an issuer ties up waiting for banking hours, and none of the announcements read for this post states a fee or a change in what merchants pay. Interchange still follows the card type, not the currency behind the card. Lumx has no say in network settlement. Its top-up converts at the market rate, and the cash-out can carry a locked quote so the cardholder sees that cost up front.
What happens in a dispute, and what if the rate moves before settlement?
A chargeback runs through the network between the issuer and the merchant's bank, and the program decides whether the cardholder is credited while it is open. A USDC balance is dollar-denominated, but a BRL or MXN cardholder bears the conversion rate at top-up and again at cash-out. Lumx is not in the dispute path. On its legs, the top-up converts at the market rate, and the cash-out can carry a locked quote of 30 seconds with no fee, or one or five minutes with a fee.
