What Is 1inch? How the Leading DEX Aggregator Works

What Is 1inch?

1inch is the leading DEX aggregator on Ethereum and EVM-compatible chains, routing token swaps across hundreds of decentralized exchanges and liquidity sources to find users the best available execution price.

In 2019, Sergej Kunz and Anton Bukov, founded 1inch during an ETHGlobal hackathon. Since then 1inch has grown from a simple aggregator into a multi-product DeFi platform that includes its own limit order protocol, a fusion mode for gasless swaps, and liquidity provision infrastructure.

The protocol processes billions of dollars in monthly trading volume across Ethereum, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche, Base, and other networks.

This guide covers how 1inch’s aggregation technology works, its product suite, how its governance and token economy function, and the risks users should understand.

How the Aggregation Engine Works

At its core, 1inch solves the liquidity fragmentation problem. When a user wants to swap Token A for Token B, the liquidity for that pair is spread across dozens of DEXs - Uniswap, SushiSwap, Curve, Balancer, and many others - each potentially offering different prices and liquidity depths. Manually checking each venue is impractical, and simply executing on a single DEX may not give the best price, especially for larger trades.

1inch’s Pathfinder algorithm analyses all available liquidity sources in real time and calculates the optimal route for each swap. This routing can involve splitting a single trade across multiple DEXs simultaneously (for example, executing 40% on Uniswap and 60% on SushiSwap), routing through intermediate tokens (multi-hop trades where Token A goes to WETH to USDC to Token B if that path offers a better final price), and combining multiple strategies to minimise total execution cost including gas fees.

The algorithm also factors in gas costs when determining routes. A route that offers a marginally better price on a low-liquidity DEX may not be worthwhile if the gas cost of accessing that DEX consumes the price advantage.

This gas-aware routing is particularly important on Ethereum mainnet where gas costs can be substantial, and differentiates sophisticated aggregators from simpler price-comparison tools.

Fusion Mode: Gasless Swaps Through Resolvers

1inch Fusion is the protocol’s intent-based trading mode, which allows users to execute swaps without paying gas fees.

Instead of submitting a transaction directly to the blockchain, users sign an order (an intent) specifying what they want to trade. This signed order is then picked up by professional market makers called resolvers, who compete to fill the order at the best possible price.

The resolver pays the gas fee and executes the trade on behalf of the user, making the swap effectively gasless for the user. Resolvers profit from the spread between the price they fill the order at and the price they can obtain on the open market.

A Dutch auction mechanism ensures competitive pricing, Here is how is works, the order starts at a price favourable to the user and gradually becomes more favourable to resolvers over time, creating urgency for resolvers to fill quickly before competitors do.

Fusion mode represents the broader industry trend toward intent-based trading, where users express what they want and professional solvers compete to provide the best execution.

This model can often achieve better prices than direct on-chain routing because resolvers can access private liquidity, use cross-DEX arbitrage, and optimise execution in ways that on-chain routing algorithms cannot.

The Limit Order Protocol

1inch includes a decentralized limit order protocol that allows users to place orders at specific prices without locking funds in a smart contract.

Users sign an off-chain order specifying the tokens, amounts, and price, and the order becomes available for anyone to fill when market conditions match. This design is gas-efficient, creating and cancelling orders is free (only signing a message), and gas is only paid when an order is actually filled.

The limit order protocol powers several features beyond simple limit orders. Conditional orders can be created with custom logic.

For example, orders that only become fillable when a specific on-chain condition is met. Range orders allow users to create multiple limit orders across a price range.

Stop-loss functionality enables automated position management based on price thresholds.

The 1INCH Token

1INCH is the protocol’s governance and utility token. Token holders participate in governance through the 1inch DAO. They vote on proposals that affect protocol parameters, fee structures, resolver registration requirements, and treasury allocations.

The governance process uses Snapshot for off-chain voting on proposals that are then executed on-chain.

1inch employs a staking model where users lock 1INCH tokens to participate in governance and earn rewards. Stakers receive Unicorn Power, which determines their voting weight and their share of resolver fees and protocol incentives.

The staking mechanism uses a delegation model where stakers can delegate their Unicorn Power to resolvers. This helps resolvers meet minimum staking requirements while earning a share of resolver profits.

The token economy creates a symbiotic relationship between stakers and resolvers.

Resolvers need delegated stake to operate, stakers earn a share of resolver profits, and the competitive resolver market drives better execution for users.

This alignment of incentives is designed to ensure that as trading volume grows, value flows back to token holders through the resolver ecosystem.

Multi-Chain Presence

1inch operates across all major EVM networks including Ethereum, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche, Base, Gnosis Chain, Fantom, zkSync, and others.

Each deployment connects to the liquidity sources available on that specific chain, and the Pathfinder algorithm is optimised for each network’s characteristics (gas costs, block times, available DEXs).

The multi-chain strategy is essential for an aggregator because liquidity fragmentation exists not just across DEXs within a chain but across chains themselves.

By being present on all major EVM networks, 1inch captures swap volume wherever it occurs and provides a consistent user experience regardless of which network a user is on.

Competitors and Alternatives

In the EVM DEX aggregation space, 1inch competes with several notable alternatives.

Paraswap offers a similar aggregation service with its own routing algorithm and a token with staking utility.

0x/Matcha provides aggregation through both an API (used by many other applications) and a consumer-facing interface.

CoW Swap uses a batch auction model where trades within a batch can be matched against each other, potentially offering better prices by eliminating MEV (maximal extractable value).

UniswapX represents Uniswap’s entry into the intent-based trading space, using a filler network similar to 1inch’s resolver model.

On Solana, Jupiter dominates the aggregation market.

Portals.fi provides cross-chain aggregation that spans both EVM and non-EVM chains from a single interface.

1inch differentiates through the breadth of its product suite (aggregation, fusion mode, limit orders), its extensive multi-chain deployment, and the maturity of its resolver network.

The protocol’s long track record and developer-focused API have also made it a popular backend for other applications that need swap functionality.

Risks and Considerations

While DEX aggregation is relatively lower-risk compared to lending or leveraged trading (users approve and execute individual swaps with known parameters), several risk factors apply.

Smart contract risk exists across 1inch’s routing contracts, limit order protocol, and fusion settlement contracts. A vulnerability in any of these could potentially be exploited during the swap process.

Routing risk is a subtle concern, if the aggregation algorithm miscalculates optimal routes or fails to account for rapid price changes between route calculation and execution, users could receive worse execution than expected.

Slippage tolerance settings mitigate this, but users should understand how to set appropriate slippage limits for their trades.

Fusion mode introduces resolver trust assumptions. While the system is designed to be competitive and trust-minimised, users are relying on resolvers to execute their orders fairly.

The Dutch auction mechanism and competitive market structure generally ensure good execution, but during periods of extreme volatility or resolver network disruption, fills may be delayed or suboptimal.

Token approval risk applies to all DEX aggregators - using 1inch requires approving token spending permissions for the protocol’s contracts.

Users should be aware of what approvals they are granting and consider revoking unused approvals.

MEV risk (sandwich attacks, front-running) affects on-chain swaps routed through public mempools, though Fusion mode and private transaction submission can help mitigate this.

Exploring 1inch via Portals.fi

Portals.fi is a DeFi aggregation platform that allows users to access swap routing, cross-chain functionality, and DeFi protocol interactions through a unified interface.

Users can compare execution across different routes and manage their DeFi activities from a single access point.

This article is for informational purposes only and does not constitute financial advice. DeFi protocols carry inherent risks including smart contract vulnerabilities and execution risk.

Always conduct your own research before interacting with any protocol. For our full disclaimer, please visit disclaimer.