A Complete Guide to the 1inch Swap

1inch is a leading DeFi aggregator that aims to make crypto trading more efficient and user-friendly. Its Swap product combines liquidity from many sources to get you the best token prices and offers multiple ways to trade, including across different blockchains. This guide breaks down all three swap modes on 1inch — Simple, Advanced, and Limit Order — and shows how Fusion and Fusion+ enable gas-free swaps and cross-chain trades. You will also learn about 1inch’s security stack and why it sees itself as a step up from conventional aggregators and DEX platforms.

KEY TAKEAWAYS➤ 1inch Swap supports multiple modes including Simple, Advanced, and Limit Orders for flexible token trading across chains.➤ Key features include gasless swaps, MEV protection, bridgeless cross-chain execution, and advanced security with real-time screening.➤ Unlike traditional platforms, 1inch avoids bridges, aggregates deeper liquidity, and executes trades through auction-driven resolver systems.

• Swap modes on 1inch: Simple vs. Advanced vs. Limit orders
• The 1inch Fusion protocol: Intent-based gasless swaps
• Cross-chain swaps with Fusion+
• 1inch swap vs. alternatives
• Potential drawbacks
• Is 1inch Swap the right fit for you?
• Frequently asked questions

Swap modes on 1inch: Simple vs. Advanced vs. Limit orders

1inch provides a flexible trading interface with three modes to suit different user needs: Simple mode, Advanced mode, and Limit Orders. All modes use 1inch’s aggregation technologies to secure competitive rates but offer different features and levels of control.

Here’s a quick overview of the three modes:

Simple mode

This mode is designed for quick, straightforward token swaps with minimal complexity. The interface is clean and easy to use — it focuses primarily on swapping one token for another without extra charts or settings. 

Under the hood, Simple mode uses 1inch’s Fusion mechanism and Fusion+ for cross-chain swaps. No gas fees appear because resolvers cover gas costs and protect transactions from front-running. Fusion+ stands out because it lets you swap across chains without any bridges, all from one page, so you keep custody of funds and avoid bridge risks.

You don’t need to pay network fees or hold ETH or BNB for gas, as the swap is executed via resolvers who cover gas costs. 

How intent-based swaps work (Fusion & Fusion+) 

Resolvers are third-party actors who fill user swap intents on Fusion and Fusion+. You create an “order intent” that specifies what tokens you want to trade and your target price range. That intent enters a Dutch auction where resolvers compete to fill your order. When a resolver accepts the terms, it pays gas fees, pulls liquidity from DEXs or CEXs, and completes the swap on-chain. If the order expires without a match, it cancels automatically — your funds remain safe. 

Fusion+ extends this same process to cross-chain swaps. You sign an intent that names a destination chain and an acceptable rate. Resolvers must lock source-chain tokens into an escrow contract and lock target-chain tokens into a second escrow. Both escrows rely on a shared secret hash and a timelock. 

Once both sides confirm, the secret reveals, and the resolver finalizes the swap atomically. You never lose custody of funds unless the swap completes.

➤ Simple mode is ideal for users who want the best price with one click and no distractions.

Advanced mode

Advanced mode brings along the full suite of 1inch features for experienced traders. In this mode, you get access to live price charts, trade route details, and advanced swap settings.

You can view how 1inch splits your trade across multiple liquidity sources and adjust parameters such as slippage tolerance, route priority, partial-fill allowance, and preferred gas token. 

Advanced mode lets you choose Classic (Pathfinder) swap execution and adjust advanced settings. For those out of the loop, Classic swap uses the Pathfinder algorithm to split orders across liquidity sources with detailed visualisation in the UI: 

➤ Advanced mode is best suited for analyzing routes, adjusting trade parameters, and fine-tuning executions.

Limit Orders

1inch’s Limit Order feature allows users to place trades at specific target prices, which allows them greater control over execution.

Put simply, a Limit Order stays open until the market reaches your specified conditions instead of filling immediately at market price. The system, powered by the 1inch Limit Order protocol, enables fee-free order placement. 

You can specify the token, price, and expiration time (e.g., sell 1 ETH if it reaches 5,000 USDC). Orders are held off-chain and filled only when the conditions are met, meaning no gas is required to place them.

Limit orders are available in advanced mode under the corresponding tab. You can also access it from the “Trade” dropdown menu on the swap section of the 1inch website.

➤ Limit orders are especially useful for automating trades at optimal prices without active monitoring, reducing both gas usage and slippage compared to manual execution.

The 1inch Fusion protocol: Intent-based gasless swaps

One of 1inch’s most powerful aspects is the Fusion protocol, which introduced intent-based, gasless swaps to DeFi. 

In Fusion mode, you can swap tokens without paying gas fees or dealing with miner extractable value (MEV) attacks — a major advantage for on-chain traders.

Fusion allows users to create an “order intent” that specifies what they want to trade and under what conditions (instead of executing a swap directly through a DEX at the current price). 

This intent functions like a flexible limit order with a price range and time window. Once signed, the order is passed to resolvers — professional market makers — who compete to fill it.

Resolvers pay the gas fees to complete the swap on-chain, so users don’t need native chain tokens like ETH or BNB to cover gas. Fusion uses a Dutch auction model to determine pricing. 

➤  Initially, the price favors users, and over time it shifts toward the resolver’s price target. This design incentivizes resolvers to fill orders early. This encourages resolvers to act early to secure a better profit margin, while still honoring the user’s price limits.

If the order reaches the end of the time window without being filled at acceptable terms, it expires without execution. 

When resolvers do execute, they pull liquidity from DEXs, centralized exchanges, and internal inventory, thereby giving users access to deep, distributed liquidity. Even large orders can be filled in parts by multiple resolvers to reduce slippage.

Gasless execution is a key benefit. Resolvers bundle your trade into their own transactions and earn arbitrage or spread, while you only pay the swap amount and a small fee included in the rate. 

MEV protection

➤ MEV (Maximal Extractable Value) refers to the profit a validator or miner can gain by reordering, inserting, or excluding transactions within a block. This often results in front-running or sandwich attacks that worsen trade outcomes for regular users.

Fusion also protects users from MEV attacks like front-running or sandwiching. Because the order is filled by a resolver and submitted as a private, bundled transaction, MEV bots in the mempool never see it. 

Some resolvers use private execution channels to further prevent any manipulation. This ensures a fairer trading environment, even for large swaps.

Fusion vs. Classic swaps

Before Fusion, 1inch swaps used a “classic” model, where trades were executed immediately and the user paid gas. Classic mode is still available and useful when instant, guaranteed execution is needed. 

However, the Fusion protocol has become the default option for Simple mode because it often provides better outcomes after factoring in gas and MEV. 

1inch’s in-house analysis claims that users save around 9.5% compared to competitor swaps using Fusion — primarily due to gas savings and execution optimization.

Cross-chain swaps with Fusion+

Cross-chain interoperability has long been a challenge in DeFi. Traditionally, swapping tokens across chains required using bridges or centralized exchanges — both of which were slow, somewhat expensive, and introduced custodial risks.

Fusion+ changes that by enabling relatively easy, bridgeless cross-chain swaps within the platform. 

You can swap tokens from one chain to another (e.g., Ethereum to BNB Chain) in a single step without relying on third-party bridges or custodians. Importantly, you retain full self-custody at all times. 

The process is atomic, meaning the swap either completes in full or fails with a refund — no partial outcomes.

How Fusion+ works

Fusion+ is built on atomic swap principles using 1inch smart contracts and resolvers. You sign an order intent specifying the token destination chain and acceptable rate when initiating a cross-chain swap. 

The intent is shared with resolvers, who monitor a Dutch auction where the price gradually drops over time. They monitor the auction with the aim of filling the order as soon as the price meets their profit target. The first resolver to accept the terms wins the auction and locks your tokens into an escrow contract on the source chain.

Simultaneously, the winner locks the target-chain tokens (from their own funds) into a second escrow on the destination chain. Both escrows use a shared secret hash and a time lock.

Once both escrows are confirmed, the “secret” is revealed, which then allows the resolver to claim the tokens on one chain and send you the tokens on the other. The entire process is coordinated to be completed securely and atomically.

Timelock and safety

If something goes wrong — for instance, if the resolver fails to deliver — the swap cancels automatically after a set time window. 

Funds are returned to the original owners. Resolvers also post a small security deposit that they forfeit if they fail to follow through. This mechanism is there to protect you from incomplete or failed swaps.

Fusion+ brings the reliability of atomic swaps into a user-friendly format, offering the same trustless guarantees but through a DeFi interface accessible to any user.

Why Fusion+ can be a game-changer

With Fusion+, 1inch delivers a somewhat unique and practical feature in DeFi: cross-chain swaps that are secure, decentralized, and require no bridges. 

The process is simple — no juggling apps, no managing gas on multiple chains, and no exposure to bridge vulnerabilities. For instance, swapping tokens from Ethereum to Polygon with Fusion+ is faster, safer, and cheaper than using a traditional bridge. You don’t pay gas on the source chain because resolvers handle gas costs on both ends. This makes cross-chain trading as easy as a standard token swap.

To cut a long story short, Fusion+ represents a major advancement in multi-chain DeFi infrastructure by removing reliance on custodial intermediaries and integrating atomic security. 

➤ Fusion+ remains under the radar for many users, yet it redefines what cross-chain trading can — and should — look like: trustless, gasless, and bridge-free.

1inch security: What protects you while swapping

The platform promises a comprehensive security stack to protect users from scams, hacks, and fraudulent activity at every step. This spans everything from smart contract audits to real-time address screening. 

Here are some of the key layers of protection 1inch offers:

• Blocklist strategy: 1inch screens wallet addresses for risk, using data from TRM Labs, Etherscan, and its own investigation team. Suspicious wallets are blocked automatically.
• Transaction simulations: The wallet shows you exactly what will happen right before you sign a trade. You see what tokens leave your wallet, what comes in, and if anything looks sketchy.
• Scam protection: 1inch has teamed up with security platforms like Blockaid to detect threats such as malicious transactions, suspicious DApps, scam domains, and phishing attempts. You’ll get an alert before connecting to anything flagged as unsafe.
• Smart contract audits: Every contract used by 1inch has been audited multiple times. Put simply, they are also non-upgradable, so no surprise code changes can sneak in.
• Front-running protection: Fusion and Fusion+ prevent bots from manipulating your trade by hiding your order until it’s executed.
• AML compliance: Resolvers must pass KYC checks before operating. Transactions are also screened for links to money laundering, scams, or hacked funds.
• Brand protection: 1inch actively removes fake websites and social scams with help from Red Points and Phishfort. This way, you stay protected even outside the DApp.

Additional protection layers on 1inch:Downtime fallback: Fusion+ has a built-in recovery phase for stalled swaps.MEV resistance: Private order handling eliminates sandwich attacks.Behavioral risk analysis: User actions are monitored (anonymously) to detect signs of compromise.

1inch swap vs. alternatives

Potential drawbacks

While 1inch Swap comes packed with practical and efficient features, there are a few potential drawbacks depending on your use case:

➤ Delayed execution in Fusion mode: Because Fusion uses Dutch auctions, your swap might not execute instantly. If you need immediate execution, Classic mode may be better.

➤ Limit orders depend on taker interest: Your order might not fill if it isn’t profitable for resolvers or takers, especially with low-liquidity pairs.

➤ Gas fees in Classic mode: If you use Classic swaps, you still need native tokens like ETH or MATIC to cover gas.

➤ Cross-chain swaps are resolver-dependent: Fusion+ relies on resolvers to complete swaps. While protected by escrow and recovery mechanisms, it is not instant like native-chain swaps.

➤ Complexity for new users: Advanced settings, presets, and auction mechanics can feel overwhelming if you are used to simpler DEXs.

Is 1inch Swap the right fit for you?

As you can see, 1inch Swap offers far more than basic DEX aggregator functionality. If you are an active trader managing assets across chains, it can be a strong alternative to simpler platforms. 

That said, the multiple modes and advanced settings may feel complex for some beginners who may prefer easier tools for basic swaps. Additionally, Fusion mode’s reliance on resolvers also introduces timing and pricing trade-offs. Overall, whether 1inch Swap suits your needs ultimately depends on how actively you trade and how much control you want.

Frequently asked questions

How does 1inch Swap work?

1inch Swap connects your trade to resolvers who compete to fill your order at the best available rate. In Fusion and Fusion+ modes, resolvers may pull liquidity from DEXs, CEXs, and private pools. Classic swaps route directly through the 1inch Aggregation Protocol, which splits orders across multiple liquidity sources to improve pricing and reduce slippage.

What is the benefit of Fusion or Fusion+ on 1inch?

Fusion allows gasless, intent-based swaps where third-party resolvers compete to fill your order at the best rate. You don’t need native tokens for gas, and your trade is protected from MEV attacks. Fusion+ extends this functionality to cross-chain swaps without bridges, using escrow contracts for secure settlement.

Can I use 1inch without holding ETH or other native tokens?

Yes, Fusion mode allows you to swap tokens without holding ETH, MATIC, BNB, or other native assets. Resolvers cover all gas costs and execute the trade on your behalf. This is especially useful for new wallets or users with only stablecoins.

What risks or limitations should I be aware of?

Fusion swaps may take longer to execute due to the auction mechanism and resolver participation. Limit orders can remain unfilled if the target price is not met or liquidity is low. Classic swaps still require gas fees and expose trades to MEV unless protected manually.