1inch is a DEX Aggregator for Split-Route Token Swaps

Split Routing for Large Same-Chain Swaps

Two or more liquidity pools can share a large 1inch swap when splitting produces a better net return than sending the entire amount through a single pool.

Consider a USDC-to-WETH trade on Ethereum. Pathfinder compares a direct Uniswap pool, a Curve path through another stable asset, and a Balancer route, then allocates portions where marginal pricing is strongest. Each added hop consumes gas, so the highest gross token output isn’t automatically the best quote. A shallow pool moves farther along its pricing curve as order size increases; splitting reduces that concentration. For a small order, one venue wins when another contract call costs more than the added output. All legs settle within the same transaction. The quote represents an executable route, not an average of displayed spot prices.

Minimum Return and Allowance Bound the Trade

One minimum-receive value places a hard floor beneath each 1inch Classic swap, while one token allowance defines how much the router may transfer from the wallet. Related details are covered in 1inch walkthrough.

Price protection starts with six fields: input amount, expected output, minimum received, route, estimated gas, and selected chain. If execution would return less than the minimum, the EVM transaction reverts; gas already spent on computation remains payable. An ERC-20 approval creates separate on-chain state. A fixed allowance persists until it is consumed, replaced, or revoked, so an exact amount narrows the permission to the intended trade. Token symbols aren’t unique identifiers; the contract address and chain together identify the asset. That distinction matters for bridged versions of USDC, WETH, and other multi-chain tokens.

With the ordinary ERC-20 approval path, a first Classic trade takes up to two on-chain transactions: one approval and one swap.

Wallet and Chain Parameters Must Align

Five durable chain IDs used by 1inch - Ethereum 1, BNB Chain 56, Polygon 137, Base 8453, and Arbitrum One 42161 - bind wallet actions to the intended EVM network.

A connected wallet must hold the token being sold and the network’s native asset when the selected path charges the sender gas. ETH covers Ethereum, Base, and Arbitrum; BNB covers BNB Chain; POL covers Polygon. MetaMask, WalletConnect, and Ledger connect without transferring custody to the interface. EIP-6963 lets compatible browser wallets announce themselves to decentralized applications, reducing collisions between multiple installed wallet extensions. The wallet and 1inch must display the same chain before signing. On EVM networks, a standard address contains 20 bytes, renders as 40 hexadecimal digits, and carries a two-character 0x prefix.

These five identifiers provide a durable check before an EVM wallet signs.

Moving value across networks requires a cross-chain route such as Fusion+, while a chain switch changes only the wallet’s active network.

Classic, Fusion, and Limit Orders Match Different Intent

Three execution paths organize 1inch swaps: Classic prioritizes immediate on-chain settlement, Fusion delegates filling to resolvers, and limit orders wait for user-defined price conditions or expiry settings.

Classic Swaps

Classic mode builds one route and asks the wallet to broadcast one atomic router transaction. The user pays network gas, and every leg succeeds together or the transaction reverts. With ordinary ERC-20 approval, a first trade takes up to two on-chain transactions: one approval and one swap. Permit2 shortens that path for compatible assets and wallets.

Signed-Order Execution

Fusion and limit orders begin with an EIP-712 typed-data signature rather than an immediate swap transaction. A resolver or taker later submits the settlement, and the signature binds the order to its terms, chain, and verifying contract. A second page unpacks 1inch requirements.

Fusion Dutch Auctions

Fusion starts the exchange rate at the favorable edge of a defined range and moves it until a resolver accepts. The resolver covers settlement gas for a standard EVM Fusion fill. An order left beyond its window expires.

Limit Order Conditions

Limit Order Protocol v4 lets the maker define price, receiver, expiry, partial fills, multiple fills, and private-taker access. A nonce or epoch supports cancellation. The order remains off-chain until a taker fills it.

The Separate 1INCH Token Role

The 1INCH token’s defined total issuance is 1,500,000,000 units, and balances use 18 decimal places. It supports governance and staking, but a swap doesn’t require 1INCH as payment. Staking lock choices span 1 month to 2 years; the selected chain’s native asset covers sender-paid gas.

Gas, Pool Fees, and Price Impact Set Net Cost

Two cost layers shape a 1inch Classic quote: blockchain gas pays validators, while pool fees and price impact reduce the asset amount delivered by the selected route.

One gwei equals 0.000000001 ETH, and a plain Ethereum value transfer starts at 21,000 gas before any router or pool contract work. A Classic swap consumes more because the router calls one or more liquidity sources, transfers tokens, and enforces minimum output. Its final native-asset cost equals gas used multiplied by the transaction’s gas price. Route selection weighs that cost against token output, so another pool or hop must add enough output to justify added execution. Uniswap, Curve, and Balancer set their own pool economics; the aggregator evaluates the complete path instead of replacing those charges with one universal pool fee.

Fusion changes who submits settlement. A resolver pays gas for a standard EVM fill, while the signed return incorporates resolver compensation and any applicable infrastructure cost. Native-token, Solana, fast-mode, and very small routes follow their displayed fee path. The minimum received remains decisive because it states the execution floor in output units.

Pathfinder and Router Settlement Work as Two Layers

Two coordinated layers produce a Classic swap: Pathfinder searches candidate routes off-chain, then Aggregation Router v6 executes the chosen calldata atomically on the selected network.

Pathfinder Route Discovery

Pathfinder computes the route before the wallet signs, using the requested amount and available pool state.

Route discovery models direct pools, multi-hop paths, split percentages, token conversions, and gas. For USDC to WETH, one candidate might use a direct Uniswap pool; another might pass through DAI and Curve before reaching WETH elsewhere. The algorithm compares executable output for the actual input size, rather than a spot quote from each venue. It then encodes the winning distribution for settlement. Route quality changes with pool depth, trade size, gas price, and enabled liquidity sources. A quote therefore ages as new transactions change reserves, even though the same two-layer process produces its replacement.

Atomic Router Settlement

Router v6 receives encoded route data and enforces the caller’s minimum return within one transaction.

Router v6 and Limit Order Protocol v4 share one deployment address on many EVM networks, although network-specific exceptions use different addresses. Version 4.3.2 is an audit-tagged Limit Order Protocol v4 release, while its development branch remains work in progress. For a Classic swap, the router pulls approved input, calls the selected pools, verifies output, and sends the received token to the named recipient. A revert rolls back token state across every leg, preserving atomicity. Gas consumed before the revert remains charged by the chain, which makes a realistic minimum return and gas estimate operationally important.

Direct Pools and Competing Aggregators Offer Alternatives

Four established alternatives to 1inch frame the choice: Uniswap offers direct pool execution, Curve specializes in correlated assets, CoW Swap uses batch auctions, and ParaSwap also aggregates routes.

A direct Uniswap trade gives clear exposure to one selected route and its fee tier. Curve becomes relevant when stablecoins or similarly priced assets concentrate liquidity in purpose-built pools. CoW Swap expresses an order to competing solvers and seeks settlement through batch competition. ParaSwap searches across decentralized liquidity rather than operating a single pool. Matcha provides another aggregator interface built around 0x liquidity and routing. Comparing minimum received, gas responsibility, order-fill model, supported chain, and route transparency reveals the meaningful differences; brand familiarity alone doesn’t determine execution quality.

Cross-chain intent systems answer a separate need. Fusion+ coordinates source- and destination-chain settlement with 32-byte secrets and hashlocks; a same-chain route leaves assets on their existing network. Choose the execution model first, then compare the route.