1inch introduces Fusion+: a new standard for cross-chain swaps

Our new cross-chain solution, built with security by design, enables seamless token swaps across multiple blockchains while ensuring asset protection.  

We are thrilled to unveil Fusion+, bringing users cross-chain functionality in a breakthrough upgrade of our intent-based swap product. With Fusion+, users retain full self-custody of their assets, while the architecture ensures transactions are fully completed on the two networks involved in the swap, without relying on third parties.

1inch has been driving blockchain innovation forward since day one. We started by aggregating on-chain liquidity in the most efficient way. Next, with 1inch Fusion, we combined on- and off-chain liquidity using an intent-based approach to deliver convenient and secure swaps  designed with built-in protection against maximal extractable value (MEV).

Cross between chains with Fusion+

Now, Fusion+ is here - a true cross-chain game-changer. This upgrade pools liquidity from the entire Web3 ecosystem, enabling fast, efficient and secure cross-chain swaps - all from a single platform.

Until now, cross-chain swaps were hindered by slow, costly bridges and risks of centralized exchanges. Fusion+ changes everything by offering a decentralized, self-custodial solution that taps into the vast liquidity of Web3, ensuring users get the best rates with unmatched security.

The cross-chain swap upgrade builds on the intent-based approach introduced with the launch of 1inch Fusion in late 2022, as well as groundbreaking atomic swap technology. Here’s a quick reminder of how 1inch Fusion swaps work: users specify the minimum return they’re willing to accept, and professional traders, known as resolvers, compete to execute swaps at the most favorable rates. The pricing is determined through a Dutch auction model, where Fusion swaps' filling rates decrease over time, influenced by swap volume and user-established presets, which define price and duration limits. A smart price curve accounts for market liquidity and adjusts based on gas prices to ensure optimal execution for users. Additionally, 1inch Fusion’s intent-based architecture is designed with MEV protection, safeguarding users from maximal extractable value exploits. To dive deeper into 1inch Fusion, check out this blog post.

The power of atomic swap technology

Fusion+ integrates atomic swap technology, ensuring that cross-chain swaps are:

• secure: "atomic" swaps are designed to be all-or-nothing transactions. If a swap fails to complete for any reason (such as timelock expiration), the assets are safely returned to the original owner.
• trustless: both parties can exchange assets without the need for mutual trust, as the swap is governed by smart contracts. These contracts verify all conditions of the transaction, meaning no one needs to trust each other or a third party to make the swap happen.

A detailed description of atomic swaps with examples can be found here. The key takeaway is that the process is entirely trustless, functioning purely through verification. This critical aspect of verification is also applied in Fusion+ cross-chain swaps, which is why users must keep the Swap tab in the dApp or application (when available in the 1inch Wallet) open until the swap is fully verified, ensuring the highest level of safety.

Steps to complete a Fusion+ cross-chain swap

All technical complexities are handled behind the scenes, allowing users to enjoy a seamless and intuitive experience. Cross-chain swaps become as simple as any other transaction.

Currently, Fusion+ is in its beta version, and users who wish to try cross-chain swaps need to manually enable Fusion+ in Settings. After the testing period, Fusion+ cross-chain swaps will be automatically enabled for everyone!

For the user, a swap is a straightforward process requiring just a few clicks:

1. Go to the 1inch dApp and enable Fusion+ in Settings (this action required only during the testing period).
2. Choose the tokens and chains to swap.
3. Confirm the swap.
4. Keep the swap tab open until the process is complete!

Behind the scenes: the mechanics of Fusion+

For those interested in the technical details, here’s how the process works:

Imagine, a user holds POL tokens on Polygon and wants to exchange them for ETH on Ethereum.

• Initiating the swap: a user enters order details in the swap form, and the order is shared with resolvers. A Dutch auction begins, where the price decreases until a resolver accepts the order.
• Locking the funds: the resolver deposits the user’s POL tokens into an escrow contract on Polygon by executing the 1inch Fusion order. The escrow contract includes the secret hash, token details and a timelock. Simultaneously, the resolver deposits ETH into an escrow on Ethereum, using the same secret and conditions.
• Completing the swap: once both contracts are active on-chain, the cryptographic secret is revealed. The resolver unlocks ETH to the user on Ethereum and claims the POL tokens on Polygon, finalizing the exchange. 

• Timelock protection: if the swap is not completed within the designated time, the resolver cancels the contracts, and the funds are returned to their original owners.

Fusion+ now live in the 1inch dApp, coming soon to the 1inch Wallet

Experience seamless Fusion+ cross-chain swaps in the 1inch dApp. To be among the first to leverage these benefits, enable Fusion+ in Settings.

With Fusion+, 1inch is setting a new cross-chain standard while advancing the security and decentralization of the Web3 space.

Get started with Fusion+ for effortless cross-chain swaps!