Uniswap Labs switched on aggregator hooks on Thursday 22 October 2026, turning Uniswap v4 into a router that can fill swaps with liquidity held on other decentralised exchanges. The feature is live in the Uniswap web app and API on Ethereum mainnet, Base and Robinhood Chain, the company said in a blog post titled “Aggregator Hooks are Now Live”. Swaps that pass through those outside sources pay Uniswap protocol fees, and those fees go toward burning UNI.
“Uniswap v4 is now an aggregator,” the post says. It is the first time the fee mechanism UNI holders approved in December 2025 reaches trades that do not settle against Uniswap’s own pools. The announcement gives no fee rate, no volume figure and no burn estimate.
Uniswap says seven external sources were connected at launch and that together they account for more than 90% of DEX activity on the three chains. It did not say over what period, and the blog post does not name the seven. The protocol’s earlier versions, its token and its governance are covered on our Uniswap project page.
How Uniswap aggregator hooks route a swap to another venue
In Uniswap v4, a hook is a smart contract attached to a pool that runs extra code at set moments of a swap. Aggregator hooks use that slot in a new way. Each one wraps an outside liquidity source and presents it as a v4 pool. Any router that already reads v4 pools, Uniswap’s own included, then sees the wrapped venue as one more Uniswap pool and can send part of an order to it.
Quotes from the wrapped sources refresh every block, according to the blog, and the whole route settles in a single transaction. For the user there is “nothing new to approve”, in Uniswap’s words.
Uniswap Labs designs and maintains the hooks and has published them as open source in its v4-hooks-public repository on GitHub. DeFi Prime, which went through the code, says the base contract, BaseAggregatorHook.sol, adjusts every quote for the protocol fee: the fee comes off the output on an exact-input swap and is added to the input on an exact-output swap. If the fee or its destination is not set, the contract returns the quote unchanged. DeFi Prime says it did not check the fee settings deployed on each chain, and Coindaro could not either, since Uniswap has not published the hook addresses.
The repository holds adapters for Curve, Fluid, venues compatible with Uniswap v2, v3 or Slipstream, Maker’s LitePSM module and a UniswapX aggregator. Code in a repository does not prove a venue is live on all three chains, and neither LitePSM nor UniswapX is confirmed as a launch source. The hooks are built in-house: Uniswap’s documentation lists no aggregator hook from a third party.
Curve, Fluid, PancakeSwap V3 and Slipstream among the sources
The launch post names no venue, but Uniswap’s developer documentation on Labs-built hooks, checked on 22 October, lists Curve, Fluid, PancakeSwap V3, Slipstream, Uniswap v2 and v3 and their forks, and LitePSM, among others. It does not say which seven are live, or on which chain. The Block reports that Fluid, Curve and PancakeSwap are among the sources available at launch. The same documentation says nothing about fees, audits or contract addresses.
Robinhood Chain, the third network, is the one ARK Invest says earned more than Ethereum in the third quarter, as we reported in our piece on Robinhood Chain’s Q3 revenue.
The design itself is not brand new. According to The Block, the first aggregator hook went live in March 2026 on the Tempo payments chain, and only in the web app. Uniswap first proposed the hooks in its UNIfication plan of November 2025, which listed them among the products where protocol fees would eventually apply.
Protocol fees feed the UNI burn, at a rate nobody has published
The economic point of the launch fits in one sentence of the blog: “Outside sources become v4 pools, and swaps routed through them pay protocol fees, contributing to UNI burn.” Until now, the fees switched on under UNIfication came from trades in Uniswap’s own pools. With the hooks, Uniswap takes a cut of volume that ends up in someone else’s liquidity.
How large that cut is, nobody outside Uniswap Labs can say. Neither the blog nor the coverage by Unchained and DeFi Prime gives a fee rate, a revenue estimate or a burn projection, and no figure exists for the volume routed through the hooks so far. The only large number in the announcement is Uniswap’s cumulative volume, more than $4.5 trillion by its own count. For UNI holders, the hooks add a second stream to the burn next to the fees from Uniswap’s own pools, of a size nobody can yet measure.
What Uniswap v4 hooks change for traders and liquidity providers
Traders: deeper routes and one more fee
Web app users get the outside sources included automatically, and developers on the Uniswap API can route through them. Large orders get access to liquidity spread across several venues, which, as Cryptonomist puts it, can reduce slippage in thin markets where a single pool runs out of depth. Nobody has published measured results. The cost is the protocol fee on the routed legs. With its size unknown, a trader cannot yet tell when the better fill outweighs it. Comparing the final quote with a dedicated aggregator such as 1inch is still the only practical check.
Liquidity providers: nothing new on the Uniswap side
Uniswap’s blog does not mention LPs at all. According to DeFi Prime, the public base hook refuses deposits with a LiquidityNotAllowed error: it only routes swaps against the liquidity pools that already exist on the wrapped venue. Uniswap’s own LPs gain nothing directly.
LPs on Curve, Fluid and the other sources may see more order flow. Whether the Uniswap fee taken on top changes their own fee income, nobody has explained, and that question stays open.
From the UNIfication vote to fees on routed trades
UNIfication passed a governance vote that closed on Thursday 25 December 2025 with 99.9% support, more than 125 million UNI for and 742 against, according to The Block. At around 04:30 UTC on 28 December, about 100 million UNI, worth roughly $596 million at the time, were burned from the treasury onchain, Cointelegraph reported.
The package switched on protocol fees for Uniswap v2 and selected v3 pools on Ethereum, set Uniswap Labs’ interface fees to zero and sent Unichain’s net sequencer fees to the burn. Reports at the time put UNI’s circulating supply near 730 million of a 1 billion maximum.
UNI fell 7.5% on the day of the launch
The launch did not lift the token. UNI traded at $7.01 at 16:34 UTC on 22 October, down 7.53% over 24 hours and 4.41% over seven days, according to market data checked by Coindaro. It had closed 21 October at $7.45, per CoinGecko. The whole market was falling at the same time: total crypto capitalisation stood at $2.75 trillion, down 5.86% over 24 hours, with bitcoin near $81,540 and ether at $2,393 at 16:34 UTC.
October has been a poor month for DeFi tokens. Criptovaluta.it counted UNI down 20.64% and Ethena’s ENA down 25.33% since 1 October, with all ten of the largest DeFi tokens negative for the month after a third quarter in which the sector led the market. That 20% is a month-to-date figure, not one day’s move, and the outlet named no single trigger.
What Uniswap has not published yet
Several basic facts are still missing:
- the protocol fee rate, and where the fee goes, on each of the three chains;
- the volume routed through the hooks since they went live;
- which seven sources are live on which chain, and the period behind the 90% claim;
- the hook contract addresses, which would let anyone read the fee settings onchain;
- any audit of the aggregator hook contracts, which none of the sources mentions;
- which chains come next, and when.