What Is 1inch? How DEX Aggregators Work
Learn what 1inch is and how DEX aggregators work. Discover how 1inch finds better prices by splitting trades across multiple exchanges. Beginner-friendly guide with examples.
What Is 1inch? How DEX Aggregators Work
1inch is a decentralized exchange (DEX) aggregator that scans multiple liquidity sources to find the best trade routes for users. Instead of interacting with a single DEX like Uniswap or SushiSwap, 1inch splits a single trade across several exchanges to get you a better price and lower slippage. Think of it as a smart shopping assistant that compares prices at every store in a mall, then buys parts of your shopping list from different stores to save you money.
What Is 1inch?
1inch is a DEX aggregator protocol launched in 2020 on the Ethereum network. It aggregates liquidity from dozens of decentralized exchanges, including Uniswap, Curve, Balancer, and PancakeSwap, as well as automated market makers (AMMs) and liquidity pools. When you want to swap Token A for Token B, 1inch does not simply route your order through one exchange. Instead, it uses its own Pathfinder algorithm to discover the most efficient path — often breaking your order into smaller chunks sent to multiple exchanges simultaneously.
The name "1inch" comes from a physical 1‑inch pipe fitting that connects multiple pipes of different diameters. The protocol acts as that fitting, connecting traders to all the liquidity sources in DeFi. As of 2025, 1inch operates on Ethereum, Binance Smart Chain, Polygon, Avalanche, Arbitrum, Optimism, and several other networks.
How DEX Aggregators Work
A DEX aggregator is software that pulls liquidity data from multiple decentralized exchanges and presents a single interface for swapping tokens. Instead of checking each DEX individually, the aggregator’s algorithm evaluates all available routes and selects the one that nets you the most tokens after accounting for fees, slippage, and gas costs.
The Pathfinder Algorithm
At the heart of 1inch is the Pathfinder routing algorithm. It performs the following steps:
- Scans multiple DEXs – queries prices, liquidity depth, and fees on each source.
- Evaluates split orders – if splitting 70% through DEX A and 30% through DEX B yields a better average price than 100% through DEX C, it chooses the split.
- Considers multi-hop swaps – sometimes going Token A → Token C → Token B is cheaper than a direct swap because of arbitrage or fee differences.
- Computes gas costs – a very split order could incur higher gas, so Pathfinder balances savings against transaction fees.
The algorithm outputs a single swap transaction that executes all the chosen routes atomically — meaning either all parts succeed or none do. This removes the risk of partial fills.
Example: Swapping ETH for USDC
Suppose you want to swap 10 ETH for USDC on Ethereum at a given moment. Without an aggregator, you might go to Uniswap and pay the price quoted there. But Uniswap’s liquidity pool may have a shallow curve for large amounts, causing high slippage.
With 1inch, the process is:
- You enter the amount on app.1inch.io.
- 1inch’s Pathfinder checks Uniswap, Curve, Balancer, SushiSwap, and others.
- It discovers that splitting your 10 ETH into three parts — 4 ETH on Curve, 3.5 ETH on Uniswap, and 2.5 ETH on Balancer — yields more USDC than putting all 10 ETH into any single exchange.
- The algorithm also checks if a two‑hop route (e.g., ETH → DAI → USDC on a specific pair with lower fees) is beneficial.
- It presents you with a combined quote showing the final USDC amount and estimated gas fee.
- You confirm the transaction, and the smart contract executes all splits in one go.
| Feature | Single DEX (e.g., Uniswap) | 1inch DEX Aggregator |
|---|---|---|
| Price source | One liquidity pool | Dozens of pools across multiple DEXs |
| Slippage for large trades | Can be high due to limited depth | Lower by spreading order across pools |
| Gas efficiency | One simple swap transaction | Optimized route to minimize gas relative to savings |
| Token coverage | Only tokens in that DEX’s pools | Many tokens available across aggregated sources |
| Safeguards | Standard slippage settings | Additional protections like “multi‑path” execution |
Why Use a DEX Aggregator?
For beginners, the main reason is better prices. Because aggregators like 1inch canvass many exchanges, they often find a quote that is a few tenths of a percent better than any single DEX. Over many trades, that adds up. Additionally, aggregators protect users from front‑running and sandwich attacks by using private mempool technologies (e.g., Flashbots) when available.
Another advantage is convenience. Instead of jumping between Uniswap, SushiSwap, and Curve to compare rates, you get a single interface that does the comparison automatically. 1inch also offers limit orders and farming features, though the core value is the swap aggregation.
Practical Example: Swapping a New Token
Imagine you found a new token “XYZ” that is only listed on two small DEXs, DEX‑A and DEX‑B. You hold 100 USDC and want to buy as many XYZ tokens as possible.
- Without 1inch: You check DEX‑A: 100 USDC gets you 500 XYZ. You check DEX‑B: same amount gets you 480 XYZ. You use DEX‑A. But you missed the fact that you could have used DEX‑A for 60 USDC and DEX‑B for 40 USDC to average a better rate, because the liquidity curves differ.
- With 1inch: The aggregator sees that DEX‑A’s pool is thick for small amounts but thins out quickly, while DEX‑B has a flatter curve. It finds that swapping 70 USDC on DEX‑A and 30 USDC on DEX‑B yields a combined 530 XYZ — 6% more than using DEX‑A alone. This is a realistic outcome because aggregators optimize for marginal liquidity.
Potential Risks and Warnings
⚠️ Warning: One common mistake beginners make is assuming the aggregator always gives the best deal without checking the “max slippage” setting. If you set slippage too low (e.g., 0.1%) and the market moves slightly, your transaction may fail — but you still pay gas for the failed attempt. Conversely, setting slippage too high (e.g., 5%) may expose you to sandwich attacks. Always start with the aggregator’s recommended slippage (usually 1–2%) and manually verify extreme swaps before confirming.
Another risk is smart contract risk. 1inch is audited and battle‑tested, but aggregators that route through multiple DEXs interact with many external contracts. Use the official 1inch frontend (app.1inch.io) and never approve tokens on a suspicious site.
Conclusion
1inch is a powerful DEX aggregator that helps traders get optimal token swaps by splitting orders across multiple decentralized exchanges. It solves the fragmentation of liquidity in DeFi, saving users money and time. By understanding how DEX aggregators work, beginners can trade more efficiently while avoiding the pitfalls of single‑exchange reliance. Whether you are swapping small amounts or large positions, using an aggregator like 1inch is one of the simplest ways to improve your trading outcomes in decentralized finance.
