# Circle StableFX goes live on Arc > Circle switched on StableFX on Arc for vetted institutions: 24/7 RFQ FX with onchain payment-versus-payment settlement. Developer docs currently list USDC and EURC. - **Source:** https://ptycoin.com/en/posts/2026-09-24-circle-stablefx-arc-fx/ - **Published:** 2026-09-24 - **Category:** News - **Author:** Mateo - **Tags:** stablecoins, payments, institutional, latam, treasury, cross-border - **Also published in:** [Español](https://ptycoin.com/es/posts/2026-09-24-circle-stablefx-arc-fx/) --- **Circle** switched on **StableFX** for vetted institutional counterparties on **Arc**, the Layer 1 the company took to public mainnet on **16 September 2026**. [CryptoSlate](https://cryptoslate.com/circle-launches-24-7-stablecoin-fx-engine-as-it-chases-a-slice-of-the-10-trillion-currency-market/) dated the live coverage **23 September 2026**: screened businesses can request competing quotes at any hour and settle both legs of a supported stablecoin pair onchain, together, or not at all. ## RFQ execution, then escrow on Arc [Circle's developer overview](https://developers.circle.com/stablefx) describes StableFX as an institutional engine on Arc that combines **request-for-quote (RFQ)** execution with onchain settlement. Payment firms, fintechs, crypto OTC desks, and prime brokers that pass Circle's screening get one API instead of a stack of bilateral FX lines. Circle's [November 2025 product post](https://www.circle.com/blog/introducing-circle-stablefx-and-circle-partner-stablecoins) said access is limited to approved institutions that complete know-your-business and anti-money-laundering checks. The trade path splits in two. A taker posts a currency pair, a size, and a settlement window. Approved liquidity providers compete on the quote. Execution is offchain. Counterparties then fund a smart-contract escrow on Arc. Settlement is **payment-versus-payment (PvP)**: both stablecoin legs move, or neither does. Circle's [taker quickstart](https://developers.circle.com/stablefx/quickstarts/fx-trade-taker) walks a **USDC** to **EURC** ticket with an `instant` tenor. CryptoSlate also notes firms can defer completion to an agreed window so a treasury desk can match the trade to its funding clock. That design is aimed at a currency market CryptoSlate puts at nearly **$10 trillion** in daily turnover, still built around banking hours. Circle's own [Arc mainnet release](https://www.circle.com/pressroom/circle-launches-arc-mainnet-an-economic-operating-system-for-the-internet) on 16 September 2026 called StableFX "24/7 programmable FX trading with near-instant, low-cost settlement." CEO **Jeremy Allaire**, quoted by CryptoSlate, called it a "strong emerging primitive" for atomically settled, real-time onchain foreign exchange. None of this is a retail book. Circle screens counterparties and, in CryptoSlate's read, limits the venue to eligible incorporated businesses. ## Documented live currencies are USDC and EURC [Circle's supported-currencies page](https://developers.circle.com/stablefx/references/supported-currencies) currently lists two tokens for StableFX swaps: **USDC** and **EURC**. The taker quickstart uses that same dollar-euro example. The overview says the engine "will expand to a broad range of local stablecoin pairs." Circle has not published a complete list of extra pairs already open for live trading. That gap is the Latin American story. The Arc launch copy is much wider than the docs. Circle's 16 September release said local stablecoins "active or onboarding to StableFX include" **BRLA**, **MXNB**, and wrapped regional units **wARS**, **wBRL**, **wCLP**, **wCOP**, **wMXN**, and **wPEN**, alongside USDC, EURC, and a longer global list. "Active or onboarding" is Circle's phrase. It describes a pipeline. It does not confirm that a desk in São Paulo or Mexico City can RFQ those pairs today. The [Partner Stablecoins program](https://www.circle.com/blog/introducing-circle-stablefx-and-circle-partner-stablecoins) is a separate layer. In November 2025 Circle named anticipated participants including **Avenia** (**BRLA**) and **Juno** (**MXNB**), with a pitch that members would plug into Circle Payments Network and StableFX flows. A name in that program, or a token live on Arc, is still not a row on the supported-currencies list. For a treasury or FX desk that already holds BRL-, MXN-, or ARS-linked stablecoin inventory, the operational pitch is overnight rebalancing when Pix, SPEI, or correspondent FX windows are closed. CryptoSlate makes the same point without volumes: a payments firm could rebalance across currencies on a weekend. There are no public ticket sizes, fill rates, or Latin American flow numbers for StableFX, and we are not inventing them. The last mile is still fiat. CryptoSlate notes that StableFX exchanges digital currencies and does not, by itself, credit reais or pesos to a bank account. Partner-issued tokens still need mint and redeem with their issuers, plus custody and local payout rails. Circle Mint can source USDC and EURC and convert to fiat in supported markets; that path does not automatically cover BRLA, MXNB, or the wrapped units. Arc's other day-one claims (fees in USDC, sub-second finality, a permissioned validator set Circle said includes names such as BlackRock, Visa, Mastercard, and MoneyGram) explain why Circle wants FX on this chain. They are not a usage report. ## Takeaway StableFX is live on Arc for screened institutions, with RFQ execution and onchain PvP settlement, and with **USDC/EURC** as the pair Circle's own docs currently document. Watch the [supported-currencies](https://developers.circle.com/stablefx/references/supported-currencies) page for whether BRLA, MXNB, or the wrapped LatAm units ever join that list. If you run a payments or treasury book in Brazil, Mexico, or elsewhere in the region, the useful check is still whether you have a redemption path with those issuers, not whether they appeared in a launch brochure. This is reporting on a product going live, not an invitation to trade it. --- ## Keep reading - [What is Bre-B? Banco de la República's instant-payment keys move pesos in about 20 seconds, and you can buy or cash out USDT only when the venue's deposit screen actually lists that rail instead of PSE](https://ptycoin.com/en/posts/2026-09-08-what-is-bre-b-colombia-stablecoins/index.md): Bre-B is Colombia's instant-payment rail: a llave, about 20 seconds, 24/7. Buy or cash out USDT only if the venue lists Bre-B; many still use PSE. - [How do you receive money in Mexico with stablecoins and SPEI? USDT or USDC lands on-chain or at a Mexican exchange, you sell for pesos, and SPEI pushes MXN to your 18-digit CLABE when CURP and bank details match](https://ptycoin.com/en/posts/2026-09-01-receive-money-mexico-stablecoins-spei/index.md): Receive USDT or USDC in Mexico, sell for pesos, SPEI to your CLABE. CURP, network choice, and matching names decide whether the cash-out clears in minutes. - [How do you buy and cash out USDT with Pix in Brazil? Deposit BRL at a local exchange, buy Tether, withdraw on-chain, then reverse the path to send reais back to your bank](https://ptycoin.com/en/posts/2026-08-25-buy-cash-out-usdt-pix-brazil/index.md): Buy USDT with Pix in minutes at a Brazilian exchange, withdraw to self-custody, then sell and Pix the reais home. Network choice and the R$35k DeCripto line matter. --- Source: PTYcoin — https://ptycoin.com/en/posts/2026-09-24-circle-stablefx-arc-fx/. Free to read and cite with attribution to ptycoin.com. AI-usage terms: https://ptycoin.com/en/ai-usage/