B2B stablecoin payment integration

A stablecoin payment is a transfer settled in a token whose value is pegged to an official currency, usually the dollar or the euro. In the EU that token is an e-money token (EMT): MiCA treats it as electronic money and requires the issuer to redeem it at any time and at par. That is why the amount you collect does not move the way a conventional cryptocurrency does. What a stablecoin is, and which types exist, is covered in the glossary.

For a business, the practical difference comes down to three things:

• Settlement in minutes, any day. The transaction confirms on the network itself, with no correspondent banks or clearing windows. That is what Visa is after when it settles in USDC on Solana with US banks such as Cross River Bank and Lead Bank: seven-day availability.
• A fee per transaction, not per amount. Network fees are charged per transaction, not as a percentage. On large amounts the gap against an international wire can be wide; on small ones it may not pay off, and it is worth running the numbers before integrating anything.
• Data that reconciles itself. Every payment leaves its identifier (the transaction hash), amount and time on-chain, and can be matched to an invoice without retyping it.

When it does not pay off. For euro payments inside the EU, Regulation (EU) 2024/886 requires, on a phased timeline, providers that offer credit transfers to offer instant transfers too, which the payee's bank must credit within ten seconds, any day. There, a stablecoin adds a conversion and a custody setup you do not need. Nor does it pay off if your customer or supplier cannot receive it or convert it through an authorized provider in their country. Where it does add value is in payments outside the euro area, especially outside banking hours, or when a payment has to trigger on its own once a condition is met.

These are the five flows where companies use stablecoins, and what has to be decided in each:

If you sell online to many customers, what you need is a crypto payment gateway; this page covers flows between companies, with large amounts and accounting reconciliation.

In Latin America the rules change at every border:

• Mexico. In June 2021, Banxico, the Finance Ministry (SHCP) and the banking regulator (CNBV) stated that offering peso or foreign-currency balances through “stablecoins” has not been authorized, and that financial institutions may not offer virtual-asset transactions to the public.
• Brazil. Since February 2, 2026, international payments or transfers with virtual assets are part of the foreign-exchange market (BCB Resolution 521). A virtual-asset service company may only make them up to the equivalent of USD 100,000 when the counterparty is not authorized to operate in foreign exchange.
• Colombia. The Financial Superintendence warns that crypto-asset transactions are neither regulated nor supervised by any state authority. The tax agency (DIAN), however, requires digital-asset service providers to report their users' conversions between pesos and digital assets from tax year 2026.

Country-by-country detail is in stablecoins in Latin America: regulation by country.

Accepting a payment on a public network is the solved part. What does not come solved is getting that payment into your billing cycle with the right reference, showing it to your finance team where they see everything else, and closing the month without manual work. The integration has five parts:

1. Entry point: gateway or API. To collect from many customers, a payment provider's gateway is enough. Stripe, for example, documents that it accepts USDC on Ethereum, Solana, Polygon, Base and Tempo, up to USD 10,000 per transaction, and settles completed payments in your Stripe balance in your local currency; it offers this to US businesses and, in private preview, to businesses in the EU, Hong Kong, Mexico and Switzerland. For supplier payments, settlements or large amounts, the integration runs through an authorized provider's API or from the company's own wallet.
2. Company wallet. Held by an authorized custodian, or self-custodied with multisig: who signs, with what limits, and what happens when someone is unavailable. If a third party holds it, in the EU it must be an authorized CASP or a financial entity enabled under Article 60 of MiCA (a credit institution or an investment firm, for example; an e-money institution only for the EMTs it issues itself). The trade-offs are in custodial vs non-custodial wallets, and how we build it, in wallet and custody development.
3. On-ramp and off-ramp through an authorized provider. Swapping dollars or euros for stablecoins and back (on-ramp and off-ramp) is a crypto-asset service, the “exchange of crypto-assets for funds”, provided by an authorized CASP, or done by the issuer itself when it issues and redeems. You choose the provider; we connect your systems to its API.
4. ERP reconciliation. Each payment reaches your ERP or billing system with the invoice reference, date, network, hash, token amount and fiat value, plus the source of the exchange rate. Without that, the operational gain disappears into spreadsheets.
5. Accounting and tax. How the balance is booked, at what rate and with what tax treatment is your advisor's call: we do not give that advice. What we deliver is the evidence, an exportable per-transaction record your advisor and auditor can review. Note that under DAC8 (Directive (EU) 2023/2226), which Member States had to apply from January 1, 2026, crypto-asset service providers report their clients' transactions to the tax authority, companies included (with exceptions such as listed companies).

We work on infrastructure and providers that already run, and build the layer that connects them to your systems. That keeps scope and risk below what building your own platform, and then maintaining it, would carry.

Which stablecoin. In the EU, the issuer of an EMT must be authorized as a credit institution or an e-money institution and must have notified and published its white paper; other persons may offer it to the public only with the issuer's written consent (MiCA, Article 48). ESMA's interim register, updated on October 30, 2026, lists 25 EMT issuers, none supervised in Spain. Some examples:

Which network. The one that both your company's provider and your counterparty's support natively, so you do not depend on a cross-chain hop. Watch out for bridged versions: Circle warns, for example, that USDC.e on X Layer is not issued or backed by Circle. For USDC, EURC and PYUSD on Solana, see our guide to stablecoins on Solana: USDC, EURC and PYUSD; for euro ones, euro stablecoins and MiCA; and for what Spanish banks are building, bank stablecoins.

In the United States, the GENIUS Act (Public Law 119-27, signed July 18, 2025) limits payment stablecoin issuance to permitted issuers (Sec. 3(a)) and bars them from paying interest or yield for holding them (Sec. 4(a)(11)). From July 18, 2028, a digital asset service provider may not offer or sell in the US a payment stablecoin from an issuer that is not permitted, subject to the law's exceptions, such as foreign issuers under a regime the Treasury deems comparable (Secs. 3(b)(1) and 18). What the law requires of issuers is in our GENIUS Act guide for issuers.

What the rules require, by role. The key question is whether you pay or collect on your own account, or hold, convert or transfer for others:

The Travel Rule in practice. Since December 30, 2024, Regulation (EU) 2023/1113 has required CASPs to send, with every transfer, the name and distributed-ledger address of sender and recipient, plus further originator data: their address, official ID number and customer number or, instead, their date and place of birth (the Travel Rule). For your company it has two effects:

• If you pay from a self-hosted wallet to a supplier that receives at an EU exchange, that exchange must obtain and keep your data as originator.
• If you move more than EUR 1,000 from your CASP account to a self-hosted company wallet, the CASP must assess whether that address is owned or controlled by you. It pays to be able to prove it, for example by signing with that wallet.

Customer identification (KYC) and anti-money-laundering checks are run by the provider that holds or converts; your flow has to be ready to hand it the data without friction.

Status as of October 31, 2026. The GENIUS Act is not yet in effect: it applies on the earlier of January 18, 2027 (18 months after enactment) and 120 days after federal regulators issue final rules. The OCC published its final rule on October 23, 2026, effective January 18, 2027, so that remains the expected date. In Spain, since July 1, 2026, only crypto-asset service providers authorized by the CNMV or other European authorities may operate, and ESMA updates its register weekly: check the issuer and the provider on the day you sign.

What Unknown Gravity is not. We are not a regulated entity: not a CASP, not an e-money institution, not a stablecoin issuer, and we do not hold client funds. We build the technology and integrate it with the authorized provider and the advisors you choose. If what you need is the license, read MiCA (CASP) license in Spain.

We work in four phases. Each one ends in something you can show your finance leadership, and the first can end in “a bank transfer is enough”.

1. Flow assessment. What you collect and pay, from and to whom, in which countries, for what amounts and on which systems. This is where we decide whether stablecoins add anything and which flow to start with.
2. Design. Token and network, custody model, authorized provider for the ramps (you choose; we help you compare), treasury policy and a map of obligations reviewed with your advisor.
3. Pilot on a real flow. One customer or one supplier, capped amounts and automatic end-to-end reconciliation.
4. Production. Full ERP integration, limits and alerts, key rotation, auditor reports and onboarding of new counterparties.

Deliverables of a typical project:

• A map of flows and obligations, reviewed with your advisor: who pays, who holds, who converts, and which rule applies to each.
• The integration architecture (gateway or API, wallet, ramps and ERP), with the token and network choice justified.
• ERP connectors and, where settlement is conditional, smart contracts with tests and a security audit before go-live.
• Signing and limits policy, operating procedures and the exportable record for your auditor.

What it costs. There are three items. Network fees are paid per transaction and depend on the network and how congested it is. Ramp fees and, if you use one, gateway fees are set by each provider's contract; what MiCA does not allow, as a general rule, is the issuer charging to redeem an EMT. And development depends mostly on how many systems have to be touched. We do not quote a figure without seeing your systems: the first phase ends with that estimate.

If you want to walk us through your case, book a meeting. If you first need to settle the strategy, start with blockchain consulting.

Who builds it. Unknown Gravity is a blockchain and tokenization company based in Málaga, Spain, and a member of Alastria.

Sources

• EU: Regulation (EU) 2023/1114 (MiCA), Articles 3, 48, 49, 50, 59, 60 and 70; Regulation (EU) 2023/1113, Articles 14, 16 and 40; Directive (EU) 2023/2226 (DAC8); Regulation (EU) 2024/886.
• ESMA, interim MiCA register and EMT issuers file; CNMV, crypto-asset regulation (in Spanish); BOE, Law 10/2010 (in Spanish).
• US: GENIUS Act, Public Law 119-27; Federal Register, OCC final rule and FR 2026-19966; FinCEN, FIN-2019-G001.
• Latin America: Banxico, SHCP and CNBV (June 28, 2021); BCB Resolution 521; Colombia's Financial Superintendence; DIAN Resolution 000233 of 2025.
• Issuers and providers: Circle, USDC and EURC networks; EURCV white paper; Stripe, stablecoin payments; Visa (December 16, 2025).