What is Uniswap?

Uniswap is a decentralized exchange protocol for swapping cryptocurrency tokens. Its smart contracts—programs that execute on a blockchain—let users trade against pools of tokens supplied by liquidity providers, rather than wait for a matching buyer or seller.

The protocol is distinct from Uniswap Labs’ web app, an interface built and maintained by a software company. UNI is the protocol’s governance token: it lets holders participate in decisions such as treasury spending and protocol fees.

This is a form of decentralized finance (DeFi). A trader deposits one token into a liquidity pool and receives another; a liquidity provider supplies the assets available for those swaps and can earn trading fees. Providing liquidity also exposes capital to losses.

The mechanics and the choice of protocol version matter for both traders and liquidity providers:

How Does Uniswap Work?

An automated market maker (AMM) uses rules in smart contracts to price trades against a liquidity pool. Unlike an order book, it does not need to match each swap with another user’s posted order.

Buying a token from a pool removes some of that token and adds the token paid in. This changes the pool’s relative balances and the price for the next trade. Larger swaps relative to available liquidity move the price more; this is price impact.

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The Defiant

Uniswap v2 uses full-range liquidity: deposits support trading across the whole price curve rather than a chosen band. Its pools charge a 0.30% swap fee, with any enabled protocol allocation reducing the share retained by liquidity providers.

Uniswap v3, another version of the AMM, uses smart contracts that let providers concentrate their liquidity within a chosen price range. It also supports multiple fee tiers, so the same token pair can have pools with different charges.

Uniswap v4 keeps concentrated liquidity but adds hooks—additional smart contracts that customize pool behavior, including fees. It supports dynamic fees and manages pools through one shared contract instead of a separate contract for every pool. These versions are different designs, not interchangeable labels for the Labs app.

Uniswap Liquidity Provision Explained

Liquidity provision means depositing assets into a pool to facilitate swaps and earn the applicable LP fees. Liquidity mining is different: an incentive program pays additional tokens to attract liquidity.

For example, Uniswap’s initial UNI liquidity-mining program ran in September–November 2020 and rewarded providers in four selected v2 pools. Earning swap fees alone does not make every provider a liquidity miner.

In practice, this means the following happens when using Uniswap to exchange tokens:

• A trader selects the token to sell, the token to receive and the amount, then reviews the quote in an app.
• In a pool swap, the trader sends the input token and receives the output token from the pool’s reserves.
• The swap pays a pool fee. Active liquidity providers earn their applicable share; any protocol fee is governed separately.
• A liquidity provider takes the other role: supplying assets for swaps rather than simply exchanging them. In v3 and v4, the provider also chooses a price range.

Fee income is compensation for taking market-making risk, not a guaranteed return. A provider’s token balances change as trades occur, and the resulting position can be worth less than simply holding the original tokens.

A compatible wallet can be used to add liquidity. Before depositing, providers need to understand the pool’s version, fee settings and, for concentrated liquidity, their selected range.

Uniswap’s Brief History

Uniswap began as an experiment in automated token trading, before the introduction of UNI.

Hayden Adams built a proof-of-concept in October–November 2017; Uniswap launched on Ethereum in November 2018.

After losing his mechanical-engineering job at Siemens, Adams learned to write Ethereum smart contracts. His friend Karl Floersch encouraged him to implement an AMM, according to Adams’ history of Uniswap.

The early prototype supported just one liquidity provider and one ETH/token pair. Subsequent work added support for multiple providers and a way to create markets for additional tokens.

Things snowballed from there, with Pascal Van Hecke, one of Devcon 3’s attendees, giving Adams a grant. During this time, another Stony Brook alum joined them, Uciel Vilchis. Fast forward to March 2018, and Uniswap rose to a fully-featured demo. However, this happened in the crypto market’s downturn, so Adams was starting to run low on cash.

Yet, Adams persisted and made contact through Floersch with none other than Vitalik Buterin, the co-founder of Ethereum. This happened during South Korea’s Deconomy 2018 conference. In the end, Adams received a $100,000 grant through the Ethereum Foundation, and that provided enough financial security to advance the Uniswap project.

Adams originally planned to call the project Unipeg, a blend of unicorn and pegasus. In his account, Buterin suggested the name Uniswap.

How Do Uniswap Fees and UNI Differ?

Swap fees compensate liquidity providers for supplying capital. Protocol fees are a separate allocation controlled through governance, not an automatic payment to the development team. UNI is a governance token, not a liquidity-provider receipt.

UNI was launched in September 2020 with 1 billion tokens minted at genesis and a four-year allocation schedule. Holders activate voting power through delegation and can vote themselves or delegate to another address; UNI governance includes treasury spending and protocol-fee decisions.

Holding UNI does not give an individual or pro-rata claim on protocol revenue. Uniswap’s documentation describes collected protocol fees being exchanged for UNI that is permanently burned; this is different from paying each holder a cash distribution. See the UNI token documentation for the token’s supply and governance mechanics.

Networks, Costs and Liquidity Risks

Uniswap Labs’ interface charges and the protocol’s pool fees are different. Labs says it stopped charging interface fees on December 27, 2025; that does not remove pool fees or network costs.

Ethereum completed the Merge on September 15, 2022, replacing proof-of-work with proof-of-stake. The Merge changed how Ethereum reaches agreement on transactions; it was not a network-capacity expansion and was not intended to lower gas fees.

As of November 2, 2026, Uniswap’s deployment documentation lists contracts on Ethereum and networks including Arbitrum, Base and Optimism. These include Layer 2 networks, which process transactions while using Ethereum as a settlement layer. Availability depends on the protocol version and network; consult the deployment list rather than assuming every version exists on every chain.

Concentrating liquidity can make more capital available near the market price, but it does not remove risk. In v3 and v4, a position becomes inactive and stops earning swap fees when the price leaves its selected range; it becomes active again if the price returns.

Impermanent loss is the shortfall in a liquidity position’s value, before fees and costs, compared with holding the original token quantities as their relative price changes. A position can rise in dollar value and still trail that holding benchmark.

For a worked example, see what happens when a Uniswap v3 position goes out of range. Fees may offset some or all of the shortfall against holding, but there is no assurance that they will. A 0.30% pool fee is not a promised investment return.

For the trading side, The Defiant’s guide to Uniswap swap costs explains which charges reduce the tokens received and which are paid separately.

Rahul Nambiampurath is a contributing writer to The Defiant.

Correction (2026-11-02): UNI launched with 1 billion tokens, not 4 billion; liquidity provision differs from mining, UNI confers no direct fee entitlement, swap fees do not guarantee LP outperformance, and the Merge occurred in September 2022.