The decentralized finance (DeFi) landscape has evolved rapidly since the launch of the first Uniswap Protocol in 2018. Onchain trading now supports millions of users, powers hundreds of use cases, and has facilitated over $1.5 trillion in trading volume on Uniswap alone. As the ecosystem grows, so do the challenges around efficiency, cost, and security in self-custodied swaps.
To address these issues and push the boundaries of what’s possible in decentralized trading, we’re introducing UniswapX — a new, permissionless, open-source (GPL-licensed), Dutch auction-based protocol designed to optimize trades across Automated Market Makers (AMMs) and other liquidity sources.
An opt-in beta is now live on the Uniswap Labs interface for Ethereum Mainnet, with plans to expand to additional chains and the broader Uniswap app ecosystem. The full codebase is available on GitHub, and the technical whitepaper can be accessed for deeper insights into its architecture and mechanics.
Enhanced Liquidity Aggregation for Better Prices
One of the most pressing challenges in DeFi today is fragmented liquidity. With the rise of multiple fee tiers, Layer 2 solutions, and diverse AMM implementations, finding the best execution path across pools has become increasingly complex.
UniswapX tackles this by reimagining how routing works. Instead of relying solely on onchain algorithms, it leverages an open network of third-party fillers — entities that compete to fulfill user swap orders using a combination of onchain AMM pools and their own private inventory.
This decentralized competition ensures users consistently receive optimal pricing. Every UniswapX order is backstopped by the proven Uniswap Smart Order Router, which guarantees that filler quotes must outperform executions from Uniswap v1 through v3 — and eventually v4 upon release.
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As Uniswap v4 rolls out with support for thousands of custom pool designs, the routing problem will only intensify. UniswapX future-proofs the swap experience by offloading routing complexity to a dynamic, competitive network while maintaining full transparency and onchain settlement.
Gas-Free Swaps and Zero Cost for Failed Transactions
A major barrier to entry in DeFi is gas fees. Users often need native tokens like ETH or MATIC just to initiate a trade — and if the transaction fails, they still lose gas.
UniswapX eliminates this friction. Here’s how it works:
- Users sign an offchain order without paying gas.
- Fillers pick up these orders, execute them onchain, and cover the gas costs.
- The gas expense is factored into the swap price — but fillers can batch multiple orders to reduce per-trade costs and offer better rates.
Crucially, users never pay for failed transactions. If market conditions change and a swap can’t be executed profitably, there’s no cost to the user. This dramatically improves capital efficiency and user experience, especially during volatile markets.
Note: Gas may still be required in specific cases — such as initial token approvals via Permit2 or when wrapping native tokens during a sale.
This model shifts the burden of transaction management from end users to specialized infrastructure providers, enabling seamless, low-friction trading.
Built-In Protection Against MEV
Maximal Extractable Value (MEV) remains one of the most significant threats to fair onchain trading. It often results in worse prices for retail traders due to sandwich attacks and arbitrage front-running.
UniswapX turns this paradigm around by returning MEV value to swappers in the form of improved execution prices. When fillers source liquidity from private inventory, those trades are inherently immune to sandwich attacks because they don’t appear in public mempools.
Additionally, fillers are incentivized to use private transaction relays when interacting with onchain liquidity venues, reducing visibility to bots and minimizing extractive MEV opportunities.
By design, UniswapX creates a more equitable trading environment where value stays with users — not extractors.
Coming Soon: Cross-Chain Swaps Without the Complexity
Later this year, UniswapX will introduce cross-chain functionality, merging swapping and bridging into a single, seamless action.
Imagine swapping ETH on Ethereum directly for USDC on Arbitrum — all within seconds, without managing bridge-specific tokens or navigating multiple interfaces.
With cross-chain UniswapX:
- Users choose exactly which asset they receive on the destination chain.
- No need to wait for bridge confirmations or deal with wrapped intermediaries.
- Execution is fast, efficient, and fully integrated into the familiar Uniswap experience.
More details about the technical design and security model are available in the official whitepaper.
👉 See how unified trading layers are simplifying multi-chain DeFi.
Secure, Immutable, and Community-Governed
UniswapX is built on core principles that have defined Uniswap since day one: security, self-custody, and decentralization.
- The protocol runs on immutable smart contracts — no entity, including Uniswap Labs, can pause or modify them.
- All funds remain under user control until a trade is successfully executed.
- Assets are only transferred after settlement, ensuring full non-custodial safety.
- The system underwent rigorous auditing by ABDK Consulting, with results publicly available.
- A bug bounty program is active to encourage ongoing security contributions.
Like the original Uniswap Protocol, UniswapX includes a protocol fee switch — but it can only be activated through Uniswap Governance, ensuring community oversight and alignment with decentralized decision-making.
Early fillers are already operational to ensure stable auction pricing and rapid order fulfillment. As adoption grows, the filler network is expected to expand organically, driven by competition and performance.
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Frequently Asked Questions (FAQ)
Q: What is UniswapX?
A: UniswapX is a new open-source protocol that improves onchain swapping by enabling gas-free trades, better prices through decentralized fillers, MEV protection, and upcoming cross-chain functionality.
Q: Do I need ETH to swap using UniswapX?
A: Not always. Since fillers pay gas on your behalf, you don’t need native tokens for most swaps. However, initial token approvals (e.g., via Permit2) may require gas.
Q: How does UniswapX protect against MEV?
A: By using private inventory fills and private transaction relays, UniswapX prevents sandwich attacks and redirects potential MEV value back to users via improved pricing.
Q: Is my money safe with UniswapX?
A: Yes. You retain self-custody at all times. Funds are only moved once a trade is executed and proceeds are secured.
Q: Can anyone become a filler?
A: Yes. The system is permissionless. Developers and institutions can join the ecosystem by running filler infrastructure — details are available in the documentation.
Q: Will UniswapX support cross-chain swaps?
A: Yes. A cross-chain version launching later this year will allow seamless asset transfers between chains without intermediate tokens.
UniswapX represents a major leap forward in decentralized trading — combining innovation from digital markets and DeFi into a secure, user-first system. As adoption grows and the filler network expands, we expect UniswapX to become the standard for efficient, fair, and frictionless onchain swaps.
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