A stablecoin is a digital token issued on a blockchain and designed to hold a fixed value against a reference asset, almost always the US dollar. A company that receives 1,000 USDC holds a claim that the issuer will redeem for 1,000 dollars, and it can send that claim to any address in the world in minutes, at any hour, without a bank in the middle. That second property, not the peg, is why payments teams care.
The word covers three very different designs, and the difference decides whether a treasurer should touch one. This post separates them, explains what "backed" means in practice, walks through how a payment settles on a stablecoin rail, and ends with the cases where a stablecoin is the wrong instrument. We covered the concept in a shorter form in our earlier stablecoin primer; this is the operator's version.
The peg is a promise, and the reserve is what makes it credible
A dollar stablecoin trades at one dollar because the issuer promises to redeem it at one dollar and holds assets that make the promise believable. When the promise is credible, arbitrage keeps the market price within a few basis points of par: if the token trades at 0.998, someone buys it and redeems at 1.000. When the promise is doubted, the same mechanism runs in reverse and the discount widens.
The credibility comes from three things a buyer can check. First, what the reserve holds: cash at banks, short-dated US Treasury bills and overnight repo are the assets regulators and auditors accept; commercial paper, loans to affiliates and crypto assets are the ones that failed in 2022 and 2023. Second, who verifies it and how often: Circle publishes a monthly examination report by Deloitte & Touche LLP for USDC (the latest available on Circle's transparency page on September 17, 2026 covers July 2026), and Tether publishes quarterly attestations for USDT. Third, who can redeem directly with the issuer, because a peg that only institutional clients can enforce is weaker than one anybody can.
The USDC explainer and the USDT explainer go into each reserve in detail. For this post, the point is that a stablecoin is only as good as the balance sheet behind it, and that balance sheet is public. That is already more than a correspondent bank tells you about the nostro account your wire sits in for two days.
Three types, and only one belongs in a payments stack
Fiat-backed. The issuer holds dollars and dollar-equivalents one to one against tokens in circulation. USDC and USDT are the two that matter; together they account for the large majority of the roughly 257 billion dollars in dollar stablecoins outstanding, per DefiLlama's stablecoin tracker on September 17, 2026 (USDT about 183 billion, USDC about 74 billion). This is the only type Lumx settles.
Crypto-collateralized. The token is backed by other crypto assets locked in a smart contract, usually worth more than the tokens issued to absorb price swings. DAI is the reference case. The design is transparent and has survived several crashes, but the collateral is volatile and the redemption path runs through a protocol rather than a company with a bank account. A treasurer cannot call anyone.
Algorithmic. No full reserve; the protocol expands and contracts supply to defend the peg. Terra's UST was the largest, and it lost the peg in May 2022 and went to zero within a week. Every operator who lived through that week treats the category as closed. We do too.
There is a fourth label that is not a stablecoin at all: tokenized deposits and tokenized money-market funds issued by banks and asset managers. They can be useful, but they are bank liabilities or fund shares with their own rules, and they do not move freely between counterparties the way a public stablecoin does.
How a payment settles on a stablecoin rail
The mechanics matter because they explain both the speed and the failure modes. Take a Mexican marketplace paying a Brazilian seller.
The marketplace holds USDC in a wallet. It requests a quote: how many reais the seller receives for a given amount of USDC, valid for a short window. It accepts the quote and sends the USDC to the provider's address on the chosen network, say Polygon. The transfer is confirmed on the blockchain in seconds to a couple of minutes, depending on the network. The provider then pays the seller in reais over Pix (Brazil's instant payment system, run by the Central Bank), which settles in seconds, and the seller's bank shows the credit.
Three legs, two of which are instant by design: the blockchain transfer and the Pix payout. The leg that can be slow is the one in the middle, the provider's own conversion and compliance checks, and that is where operators differ. On our global payments API the whole sequence normally completes in minutes, with the exceptions described in the next section.
Compare the same payment over correspondent banking: the marketplace's bank sends a SWIFT message, a correspondent in New York debits and credits nostro accounts, a Brazilian bank receives the funds a day or two later, converts at a rate the seller never saw, and deducts fees at each hop. The money is not slower because it is far. It is slower because five institutions each need to reconcile before the next one moves.
What can go wrong, and what an operator does about it
Blockchain finality is the easy part. The hard parts are around it.
Network choice. The same USDC exists on more than 30 networks (Circle's issuance data on September 17, 2026 lists 39 chains for USDC). A token sent to an address on the wrong network is not lost by the protocol, but recovering it depends on whether the receiving provider controls that address on that network. Every provider publishes which networks it accepts per currency pair; the sender's job is to read it.
Compliance holds. A payout to a new recipient may trigger an RFI (request for information, a compliance hold that asks for a document before a transaction clears). The stablecoin has already arrived; the fiat leg waits. Good providers surface the hold with a reason and a status webhook rather than silence.
Local-rail rejections. Pix rejects a payout when the recipient's CPF (the Brazilian individual taxpayer ID) or CNPJ (the Brazilian company taxpayer ID) does not match the account holder. The funds return to the sender's balance; the operator fixes the data and retries. This is a data-quality problem, not a stablecoin problem, and it exists on every rail.
In our first year running Pix payouts I signed off on a batch of several hundred payments late on a Friday, assuming the rail would carry them the way it carried single payments during the week. About a tenth bounced on name and tax-ID mismatches that our client's onboarding form had let through, and I spent the weekend on the phone explaining to a partner why their sellers saw money leave and come back. We changed two things after that: validation of the tax ID against the account holder before a payout is accepted, and no batch releases without a rail health check. Neither is about blockchain. Both are about the last leg.
When a stablecoin is the wrong tool
If both parties bank in the same country and that country already has an instant rail, a stablecoin adds a conversion step and a counterparty and removes nothing. A Brazilian company paying a Brazilian supplier should use Pix.
If the payer needs to unwind the payment, a stablecoin is the wrong instrument. Blockchain transfers are final; there is no chargeback and no recall. Consumer refunds have to be built as a new payment in the other direction.
If the amount is small and one-off, the fixed costs of onboarding, of KYB (know your business, the verification of a company and its owners) for a corporate sender, and of learning a new rail will outweigh the savings on the spread. Stablecoins pay off on recurring flows: payroll, supplier runs, marketplace settlements, treasury moves.
And if the reason is yield, stop. A payments treasury holds stablecoins because they settle, not because someone offers a return on them. The offers that look attractive are the ones that turned into the 2022 casualties.
What this looks like when a business settles through Lumx
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, 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.
In the marketplace example above, the client never handles the token. It funds a custodial wallet in USDC, or lets a customer's deposit into a named virtual account auto-convert into one, and asks for payouts in reais. Lumx runs the quote, the compliance check and the Pix leg, and reports each state change by webhook: quote accepted, funds received, compliance cleared or held with a reason, payout settled or rejected with the bank's return code. The client's finance team reconciles against those events, not against a blockchain explorer.
We only settle fiat-backed stablecoins, USDC and USDT, on Ethereum, Polygon, Base, Tron and Stellar, and only in the pairs listed on our coverage page. The list is deliberately short. Every added network is another place a customer can send funds to the wrong address, and every added token is another reserve we would have to be willing to vouch for. The stablecoin glossary defines the terms used here, and the two explainers linked above go deeper on the tokens themselves.
Verified on September 17, 2026. Operational context, not legal, tax, or investment advice.
Cover photo: Clarisse Croset on Unsplash.
Is a stablecoin the same as a central bank digital currency?
No. A central bank digital currency is a liability of the central bank itself. A stablecoin is issued by a private company and backed by that company's reserves, which is why the quality and transparency of the reserve matter so much.
Can a stablecoin lose its peg?
Yes, and several have. Algorithmic designs such as Terra's UST collapsed entirely in May 2022. Fiat-backed tokens have traded below par for hours or days during bank stress, then recovered as redemptions proved the reserve was there. The design and the reserve decide how far a discount can go.
Which stablecoin should a business use for payments?
It depends on the corridor and the counterparty. USDC has the more conservative reserve and dominates in the United States and Europe; USDT has deeper liquidity in Latin America and Asia, particularly on Tron. Many operators hold both and let the payout destination decide.
Are stablecoin payments legal in Brazil?
Yes. Law 14.478/2022 (planalto.gov.br) created the legal framework for virtual asset service providers, and Central Bank of Brazil Resolutions 519, 520 and 521 of 2025 set the authorization regime. Providers operate under the transition rules of Resolution 520/2025 while their authorization is processed.
