1inch

Despite the name, 1inch has nothing to do with the unit of length — it is a crypto trading tool. 1inch is a decentralized exchange aggregator: instead of holding its own liquidity like a single DEX, it scans across many decentralized exchanges and professional market makers at once, then splits and routes your swap along whichever path gives the best net price after fees and slippage. You approve and sign the trade yourself, and it settles on-chain from your own wallet, so 1inch never takes custody of your funds.

It was launched in 2019 by Sergej Kunz and Anton Bukov, who built the first version at an ETHGlobal hackathon. The project later grew into the 1inch Network, adding its own swap systems and the 1INCH token for governance and network utility.

1inch's core product is its aggregation and routing engine. When you request a swap, it computes a path — often across several pools and venues in one transaction — to minimize the price impact of your trade. On top of this it built Fusion, an intent-based swap system where you specify the outcome you want and independent parties called resolvers compete to fill the order, which can reduce gas costs and protect against certain forms of front-running.

Because it is an aggregator, 1inch is often used through its own web app and wallet but also plugs into other wallets and apps as a routing back-end. The trade still executes on-chain from the user's wallet; 1inch supplies the routing, not custody.

1inch is non-custodial: it routes and executes swaps from your own wallet, so there is no company balance holding your funds to be lost, and its core aggregation contracts have handled very large volume with a strong record. Its smart contracts are audited and the routing logic itself has not been exploited to drain ordinary users.

The one notable event, in March 2025, was narrow in scope. An attacker exploited a bug in deprecated Fusion v1 resolver contracts — code run by third-party market makers, not by 1inch's users — draining about $5 million from those specific resolvers. 1inch stated that end-user funds were not affected because the flaw was limited to the vulnerable resolver contracts, and the attacker later returned most of the funds in exchange for a bounty. The risks that remain are the ones common to any DEX: approving a malicious token contract, phishing sites impersonating 1inch, and the fact that permissionless routing can still touch scam tokens. Confirm the official domain and read every approval before signing.