# UniswapX RFQ Auctions on Base and Arbitrum (/docs/changelog/completed-notifications/uniswapx-rfq-auctions-on-base-and-arbitrum)

Posted: June 13, 2026 | Effective: June 13, 2026

[UniswapX](/docs/liquidity/uniswapx/overview), Uniswap's intent-based execution layer, now runs [RFQ auctions](/docs/liquidity/uniswapx/concepts/auction-types) on Base and Arbitrum. The Uniswap API will [route swaps through UniswapX](/docs/trading/swapping-api/amm-vs-uniswapx-routing) on these chains when it offers the better priced route. With RFQ, a quoter parameterizes each order and holds an exclusivity window to fill it before the order opens to permissionless fillers.

**What changed?**

RFQ is now available for Base and Arbitrum.

* **Base** moves from Priority auctions to DutchV3 auctions. Fillers integrated against the `PriorityOrderReactor` need to update their integration to handle DutchV3 orders.
* **Arbitrum** moves from open Dutch auctions to RFQ. The winning quoter now holds an exclusivity window before the order becomes permissionless.

Filling remains permissionless on both chains, but only after the exclusivity window.

**What do I need to do?**

**If you are a Uniswap API integrator**

No action is required. You can keep requesting UniswapX by leaving the `protocols` field out of your `/quote` request, which is the existing default. To request UniswapX explicitly on these chains, include `UNISWAPX_V3` in the `protocols` field.

**If you are a filler**

To compete for order flow during the exclusivity window, join the quoter set:

* Update your integration to handle DutchV3 orders. See [Filling Dutch V3 Auctions](/docs/liquidity/uniswapx/filling/dutch-v3-chains/filling-on-dutch-v3-chains) and the reactor addresses on the [deployments page](/docs/liquidity/uniswapx/deployments#base).
* To verify ownership of your filler address, sign a message with the EOA wallet that has been submitting your fills, and Uniswap confirms it against onchain UniswapX activity.

If you have questions, you can reach out to the team [here](https://support.uniswap.org).