Uniswap on Arc, Circle's stablecoin chain

Uniswap v4 is the automated market maker Circle expects to supply spot liquidity on Circle's Arc from the first day of mainnet, and Aerodrome — now consolidating with Velodrome under the name Aero — has named Arc as one of its first two expansion targets. Neither claim originates with a Uniswap or Aerodrome governance vote that could be found in the public record, which is the single most useful thing to know before treating either as settled.

Built on Arc (builtonarc.app), the independent directory covering projects on Circle's Arc blockchain, listed [N] projects on [DATE], [N] of them recorded as live on mainnet.

Uniswap: announced by Arc, dated to mainnet

The Uniswap v4 deployment on Arc was first reported on 15 June 2026 and confirmed publicly on 17 August 2026 by Arc's own account, which said liquidity infrastructure was live on the network ahead of the mainnet launch. Coverage at the time described the scope as the v4 AMM, liquidity pools, swap routing and a developer SDK and API — effectively a full stack rather than a token listing.

Circle's 5 August press release names Uniswap twice and in two different capacities: "Uniswap" among the protocols powering liquid markets for borrowing and trading, and "Uniswap Labs" among the firms enabling access to USDC on Arc. That is a distinction worth holding onto. Uniswap Labs is a company that can ship an interface and an SDK on its own authority. The Uniswap protocol's canonical deployments have historically involved the DAO. No Uniswap Foundation or governance post announcing an Arc deployment surfaced in searches for this piece, and the pre-mainnet "live" characterisation came from the chain, not from Uniswap.

So the accurate framing on 18 September is: v4 contracts are reported deployed and were described as live pre-mainnet by Arc; Uniswap itself has not published the announcement. That is stronger evidence than a press-release mention and weaker than a protocol changelog.

Aerodrome: announced, and mid-rename

Aerodrome is the dominant decentralised exchange on Base, and its operator Dromos Labs is merging it with Velodrome on Optimism into a single protocol called Aero. That unified protocol was described as expanding first to Ethereum mainnet and to Circle's Arc, with the launch window given as the second quarter of 2026. Base remains the home chain.

Circle's August release still lists the name "Aerodrome". Anyone reconciling ecosystem lists should expect the two names to appear interchangeably for some months; they refer to the same team and the same liquidity model. The status on Arc, on the strength of the primary record, is announced. No deployment notice, pool address or launch post specific to Arc was published by Dromos as of filing.

What is observable

Arc's own facts are the firm ones. Public testnet since 28 October 2025, USDC as the gas token, EVM execution, a Malachite Tendermint-family BFT consensus with sub-second finality, a permissioned validator set, testnet chain ID 5042002 and mainnet chain ID 1243 per ChainList. Circle had not published official mainnet RPC or explorer URLs as of early September 2026, which means the ordinary method of verifying a DEX deployment — paste the factory address into an explorer — was not available to the public before launch week.

That is the practical reason to distrust any list, including Circle's, that presents day-one DEX coverage as settled. The verifiable test is a factory or pool manager address on an Arc explorer plus non-zero reserves. The directory entries for Uniswap and Aerodrome on Built on Arc record what evidence exists for each and when it was checked.

Why it matters

A stablecoin settlement chain does not strictly need a DEX to function. It needs one to be useful. Without an onchain venue, USDC on Arc is a balance that moves between whitelisted counterparties; with a deep USDC/EURC book it becomes an FX market, which is the use case Circle has pushed since the testnet release.

Two AMMs of very different character are pointed at that job. Uniswap v4's hooks let a pool enforce logic — fee schedules, access rules, oracle behaviour — which is what an institution running regulated flow tends to want. Aerodrome's model is emissions-directed liquidity, which builds depth quickly and is harder to sustain when incentives taper. Whether Arc gets durable spot liquidity or an incentive-funded launch spike is a question the first month of volume answers, and neither press release does.

For anyone deciding where to route a swap on Arc in launch week, the honest position is that Uniswap is the better-evidenced of the two and that Aerodrome should be read as announced until Dromos says otherwise.