To invoice in BRL and settle in dollar stablecoin USDC, bill in reais and convert the payment when it arrives. The invoice cannot fix the rate, which is set at conversion, weeks later. Whoever holds a fixed amount in the other currency carries the move in between: the seller on a BRL invoice, the payer on a USD one.
The same holds for pesos. A Mexican client pays by SPEI (Mexico's interbank transfer system, run by Banxico) and a Brazilian one by Pix (Brazil's instant payment system, run by the Central Bank), and the conversion is a separate event from the invoice. The rest covers when the rate is fixed, how far it moves, and paying a supplier's invoice from USDC.
When does the exchange rate get fixed on a local-currency invoice?
At conversion, never at invoicing. An invoice is a promise to pay a number of reais or pesos by a date. The conversion into USDC is a different event, and the rate belongs to it. Payment terms of 15, 30 or 60 days put that gap between the two, and no quote lasts that long.
Where the rate is fixed along the life of a local-currency invoice, with the Lumx lock windows from the docs.
Moment | Is the rate fixed? | Who carries a move |
Invoice issued, terms running | No | Whoever holds the fixed local amount |
Indicative amount shown on the invoice | No, it is a floating reference | Same |
Locked quote: 30 seconds (no fee), 1 minute or 5 minutes (fee) | Yes, inside the window | Fixed for you until the quote expires |
Payment on a per-deposit transaction with a locked quote | Yes, but the payer must pay before the quote expires | Fixed for you inside the window |
Payment on a per-deposit transaction with a floating rate | Priced at execution | You |
Payment through a standing autoconversion rule | No lock, converts at the market rate | You |
USDC in the wallet after conversion | Settled in dollars | You, in dollars |
The Lumx docs describe two kinds of rate. A floating rate is a real-time reference with no lock and no fee, meant for showing an estimate. A locked rate returns an ID that you pass on the transaction, in windows of 30 seconds (no fee), 1 minute or 5 minutes (with a fee). On a per-deposit transaction that payment window follows the rate: a locked one expires with its quote, and a floating one on Pix or SPEI stays open for one day. A deposit that arrives after the transaction expired is refunded to the sender on the same rail. For invoices paid on their own schedule, Lumx offers the standing autoconversion rule, which converts every deposit at the market rate as it lands.
Who carries the move between invoice date and payment date?
The party with a fixed amount in the other currency. The invoice currency decides who that is.
Three ways to denominate an invoice and who carries the exchange-rate move in each.
Invoice setup | What is fixed | What floats | Who carries the move |
BRL or MXN, converted when paid | The reais or pesos the payer sends | The USDC the seller receives | The seller |
USD, payer sends the local equivalent | The USDC the seller receives | The reais or pesos the payer sends | The payer |
Local currency with a re-price clause | The local amount, inside an agreed band | The USDC, inside the band | Shared |
A payer whose books are in reais wants a fixed reais total, so the first row is the usual request. The seller who agrees is long reais until the conversion runs, and if the real weakens the same invoice buys fewer USDC. The second row hands the move to the client, who may ask for a discount in return. The third is a contract term.
On Lumx the exposure ends at the conversion. Once a deposit has been converted the seller holds USDC and the rate is settled. For the period before that, hedging instruments come from the seller's bank or FX broker, and Lumx's part is the quote and the legs on either side of it.
How far the rate moves: BRL and MXN invoices across October 2026
The Central Bank of Brazil (BCB) published a PTAX (its daily dollar reference rate) dollar sell rate of 5.2079 reais per dollar on October 1, 2026, and 5.4212 on October 30. For pesos, the European Central Bank's euro reference rates give a cross rate of 18.1669 pesos per dollar on October 1 and 18.9080 on October 30. Both are reference rates, not tradable prices, and 1 USDC is treated as 1 US dollar.
What the same local-currency invoice was worth in USDC on the invoice date and on the payment date. Reference rates, before any spread or fee. The second row compares two rates one business day apart.
Invoice | Rate on invoice date | Rate on payment date | USDC at invoice date | USDC at payment date | Difference |
R$50,000, issued October 1, paid October 30 | 5.2079 | 5.4212 | 9,600.80 | 9,223.05 | 377.75 less (3.9%) |
R$50,000, rate on Fri Oct 23 vs Mon Oct 26 | 5.0377 | 5.5007 | 9,925.16 | 9,089.75 | 835.41 less (8.4%) |
MXN 500,000, issued October 1, paid October 30 | 18.1669 | 18.9080 | 27,522.58 | 26,443.83 | 1,078.75 less (3.9%) |
The first and third rows are an ordinary month. The second is one business day: PTAX went from 5.0377 on Friday, October 23 to 5.5007 on Monday, October 26, a 9.2% move in the dollar, so a client who paid on Monday instead of Friday cost the seller 8.4% of the invoice.
A real conversion also carries a spread and fees that the reference rates leave out. How those are built is covered in how stablecoin payout pricing works, and the live rate for each direction is on the pages below. On Lumx a locked quote shows the base amount, the fees and the final USDC amount before the payer pays, so the live number replaces the reference one.
Live rate pages for each direction of an invoice flow.
Leg | Live rate page |
BRL invoice paid, reais into USDC | |
MXN invoice paid, pesos into USDC | |
Supplier invoice in BRL, USDC out | |
Supplier invoice in MXN, USDC out |
How to cut the exposure when you invoice in local currency
From cheapest to most intrusive for the client:
Shorten the term. Every day cut is a day of rate risk the seller no longer carries.
Convert the moment the payment lands. Once converted, the rate is settled.
Invoice in dollars, which moves the exposure to the payer, as in the second row above. This is available only where the contract is allowed to be in foreign currency, and it may not be for a Brazilian payer. See the note at the end of the wrong-tool section below.
Add a re-price clause with a band, so that a move beyond the band adjusts the invoice.
Match the reais you collect against reais you already owe. The arithmetic is in natural FX hedging with Pix.
My recommendation to a finance team that invoices in reais is to settle the question of who carries the move on purpose, before the first invoice goes out, instead of discovering it on the payment date. I would pick the shortest term the client will accept and convert on the day the money lands, because a shorter term is the only lever that does not ask the client to change anything. A rate quoted on invoice day is a reference, and nobody should price a contract as if it were a commitment.
On Lumx the second step is a configuration. A standing autoconversion rule on a BRL or MXN account returns a static Pix QR code, or a CLABE (the 18-digit Mexican bank account number) with a reference for SPEI, and every deposit paid through it is converted to USDC or USDT and delivered to the wallet, with no per-deposit call. A rule converts at the market rate and takes no lock. A webhook marks each status of the conversion, so the seller's records show when the rate was set.
What paying a supplier's BRL or MXN invoice from USDC looks like
The mirror image has the opposite winner. A company holding USDC that owes a supplier in Brazil, Mexico or Colombia a fixed amount in reais is short reais until the payout runs. On the October 1 rate, R$50,000 cost 9,600.80 USDC. On the October 30 rate it cost 9,223.05, so a payer who waited a month spent 377.75 USDC less on the same bill. A move in the other direction would have cost more.
A locked quote fixes the amount the supplier receives, as paying an exact local amount explains. Timing is the other half: Pix and SPEI run 24/7/365 while dollar rails do not, as laid out in payout limits and cut-offs by rail.
On Lumx the supplier is registered as a destination on the Pix or SPEI rail, and the payout is a stablecoin off-ramp payout that debits the wallet. Lumx does not deduct a fee from the amount that reaches the supplier on a Pix or SPEI payout, and only the supplier's bank can charge them. On Pix the supplier sees your company's name as the payer, and on SPEI too. The transaction carries a purpose value, which the banks on the rail use for screening, and a mismatch can trigger an RFI (request for information, a compliance hold that asks for a document).
When invoicing in local currency is the wrong tool
The client pays in dollars anyway. Invoicing in reais then adds a conversion for them and a risk for you.
Terms are long and the margin is thin. A 60-day term can lose the whole margin in one move, as the October rows show. Put a band in the contract.
The amount is small and frequent. A standing rule that converts each payment on arrival handles it better than quoting each invoice.
Large single invoices. Transaction limits apply per transaction, so check them first (corporate treasury conversions).
Whether you can invoice in dollars at all is a legal question this post does not answer. A contract between two parties in Brazil may not be allowed to name a foreign currency, so ask your counsel and the client's before you pick the invoice currency. The Pix leg is a separate matter: converting reais into USDC is governed by Resolution BCB 521 of 2025, which treats it as an operation of the exchange market but not as foreign exchange. No IOF applies, because a stablecoin is not foreign currency. On Lumx, the standing rule is the tool for the small, frequent payments that make the question moot.
What collecting a BRL or MXN invoice looks like on 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, 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.
The seller is onboarded as a customer with KYB (know your business, the verification of a company and its owners) and requests a BRL account, an MXN account or both. A BRL or MXN account becomes active right after approval, and a webhook says when it can receive. Both are named accounts: the payer sees the seller's own name as the beneficiary on the Pix or SPEI payment. A foreign company can hold a BRL or MXN account in its own name without a local entity in Brazil or Mexico.
There are two ways to collect against an invoice. For one known amount, the seller creates a per-deposit transaction with the invoice total as the source amount, when the payer is about to pay and not when the invoice is issued, and gets back a Pix code for that amount, or the SPEI payment details for pesos. The quote returns the base amount, the Lumx and partner fees and the final USDC amount, so the cost is visible before the payer pays. A partner fee applies only when the request names one, and it comes on top of what the payer funds, so with a partner fee a BRL invoice asks for more reais for the same USDC; the final amount is all-in. For invoices paid on an open schedule, and for recurring ones, the standing rule from the previous section collects on a static code. The payer sends ordinary reais by Pix or pesos by SPEI and needs no USDC or crypto account, so nothing changes on the payer's side. Either way the USDC lands in the seller's wallet, on Ethereum, Polygon or Base for USDC, and the seller can hold it or pay it onward.
The pricing model is a monthly platform fee plus usage-based per-transaction fees, transparent FX on locked quotes, no pre-funding; no published plans. Live currencies and rails are on the coverage page, and the products around collection are under global payments. The path from payment to settled position is a stablecoin corridor.
Methodology and sources
Lumx product behavior comes from docs.lumx.io pages read on November 1, 2026: Exchange Rates, Transactions, Autoconversion Rules, Accounts, Coverage, Payment rail cut-off times, Transaction Limits and the on-ramp integration prompt. The BRL figures are the BCB's PTAX dollar sell rate for October 1, 23, 26 and 30, 2026, from the BCB's Olinda service. The MXN figures are USD/MXN cross rates derived from the European Central Bank's euro reference rates through the Frankfurter API, both read on November 1, 2026, and are not the Banco de Mexico FIX rate. Neither rate is a Lumx quote.
Verified on November 1, 2026. Operational context, not legal, tax, or investment advice.
Cover photo: Bergstrand Consultancy on Unsplash.
Can I invoice in BRL and settle in USDC?
Yes. Issue the invoice in reais, collect by Pix, and convert into USDC on arrival. The payer needs no USDC, and the seller carries any move before conversion. On Lumx, a BRL account returns a Pix code for the invoice amount, or a static code through an autoconversion rule, and the USDC lands in the seller's wallet.
When is the exchange rate fixed on a local-currency invoice?
At conversion. A locked quote lasts 30 seconds, 1 minute or 5 minutes, so it cannot be created on invoice day and honored weeks later. On Lumx the 30-second lock has no fee, the 1-minute and 5-minute locks carry one, and a standing autoconversion rule converts at the market rate with no lock.
Who carries the FX risk between the invoice date and the payment date?
The party with a fixed amount in the other currency. On a fixed BRL or MXN invoice that is the seller, because the USDC received floats. On a fixed USD invoice it is the payer, because the local amount floats. On Lumx the rate is settled once a deposit is converted, and instruments to cover the earlier period come from the seller's bank or FX broker.
Should I invoice in local currency or in dollars?
Invoice in local currency when the client's books are in reais or pesos and the term is short. Invoice in dollars when the term is long or the margin is thin and the contract is allowed to be in foreign currency, which it may not be for a Brazilian payer. That is a legal question for counsel, and this post does not answer it. On Lumx both work: a BRL or MXN account collects a local-currency invoice, and a USD account collects a dollar one.
Can I pay a supplier's BRL or MXN invoice from USDC?
Yes. Register the supplier as a Pix or SPEI destination and run a payout that debits the USDC wallet. On Lumx no fee is deducted from the amount that reaches the supplier, and on Pix the supplier sees your company as the payer.
