DEX Aggregators Explained: 1inch, Paraswap and Jupiter

If you’ve ever used Uniswap to swap tokens and noticed you got a worse price than expected, there’s a reason for that — and a solution. DEX aggregators scan dozens of liquidity sources simultaneously, split your trade across multiple pools, and find a route that gets you more tokens for your money. The difference can be substantial. On larger swaps, a good aggregator frequently saves 1–3% compared to trading on a single decentralised exchange directly. For a £10,000 trade, that’s £100–£300.

The mechanics are worth understanding — especially for UK investors who want to trade on-chain without quietly losing money to inefficient routing, or paying more in slippage than they need to.

Why DEXs Have Pricing Problems

A decentralised exchange like Uniswap or Curve uses an automated market maker (AMM). Instead of a traditional order book, it holds reserves of two tokens in a pool. The price is determined by a mathematical formula — typically x × y = k — based on those reserves. When you buy a token, you shift the pool’s balance, and the price moves against you. On large trades, that price impact is significant.

Liquidity is also fragmented. Uniswap v3 alone has thousands of pools across different fee tiers. Then there’s Curve for stablecoins, Balancer for weighted pools, Velodrome on Optimism, Raydium on Solana, and hundreds more. Each holds different levels of liquidity for different token pairs. A single DEX might only offer one path from token A to token B — but that might not be the cheapest one.

When I first started tracking on-chain trade quality in 2024, the variation between aggregated routes and single-DEX routes was surprising. On mid-sized swaps of ETH to a lesser-known ERC-20, aggregators found routes through intermediate tokens — ETH → USDC → target token — that ended up cheaper than the direct pair on Uniswap, even accounting for the extra hop’s gas costs. That’s the whole value proposition in one example.

How DEX Aggregators Work

A DEX aggregator does several things simultaneously when you request a swap. First, it queries the current state of liquidity across every source it monitors — Uniswap, Curve, Balancer, SushiSwap, and dozens more. Second, it calculates potential routes, including multi-hop paths that pass through intermediate tokens. Third, it uses a pathfinding algorithm to split your trade across the best combination of routes and sources. Finally, it executes the entire thing in a single transaction through its own smart contract.

That last point matters for security. Your tokens flow through the aggregator’s router contract, which handles the complex routing logic and interacts with each underlying DEX on your behalf. You approve the aggregator contract to spend your tokens, and it handles the rest atomically — meaning either the whole trade executes or nothing does. There’s no partial execution risk.

The gas cost of an aggregated trade is higher than a simple single-DEX swap. More hops, more contract calls. But on mainnet Ethereum, where a 1% price improvement on a £5,000 swap is worth £50, paying an extra £2–5 in gas for better routing is usually a sound tradeoff. On layer-2 networks where gas is negligible, aggregation is almost always worth using.

The Major Players: 1inch, Paraswap, Jupiter and CoW

1inch is the most widely used DEX aggregator on Ethereum. Founded in 2019 by Sergej Kunz and Anton Bukov at ETHGlobal New York, it now aggregates over 300 liquidity sources across Ethereum, BNB Chain, Polygon, Avalanche, Arbitrum, and Optimism. Its Pathfinder algorithm splits orders across sources in real time. The average trade routed through 1inch in 2024 was around $15,000 — well above the typical retail swap size, suggesting a significant institutional and professional user base.

Paraswap operates across similar chains and is a common choice for protocols and aggregators building on top of an aggregator layer — aggregating the aggregators, in effect. It’s used by Metamask’s swap feature and several other wallets under the hood.

Jupiter is the dominant aggregator on Solana. It processes billions of dollars in monthly volume, and given Solana’s low fees and high throughput, it’s often where Solana traders default for any swap above a trivial size. Jupiter’s route engine is particularly strong on Solana-native assets and handles the chain’s unique account-based model efficiently.

CoW Protocol takes a different approach. Rather than purely routing to AMMs, it first tries to find “coincidences of wants” — matching you directly with another user who wants the opposite trade. If someone wants to sell ETH for USDC at the same moment you want to buy ETH with USDC, CoW can match you directly, saving both parties the AMM fee and price impact. Unmatched orders then route to AMMs in the normal way. This mechanism makes CoW particularly efficient for large trades in popular pairs.

Slippage, Price Impact and How Aggregators Help

Slippage is the difference between the price you saw when you initiated a trade and the price you actually got. It happens because the blockchain is not instant — between you submitting a transaction and it being included in a block, the pool state can change. On a busy network, that gap is usually under a minute, but price movements happen fast in crypto.

Price impact is different. That’s the change in price caused specifically by your trade — the larger you trade relative to the pool’s liquidity, the more you shift the ratio and the worse your effective price becomes. A £500 swap in a £5 million pool causes minimal impact. A £50,000 swap in the same pool causes roughly 1% impact.