TL;DR
A DEX aggregator scans multiple decentralized exchanges and liquidity pools to find the best price for a token swap, often splitting orders across sources for optimal execution.
Liquidity for any token pair is spread across multiple DEXs and pools. Swapping directly on one DEX might give you a worse price than splitting your trade across Raydium, Orca, and PumpSwap. Aggregators do this automatically — they calculate the optimal route in milliseconds and execute the entire multi-hop swap in a single transaction.
Jupiter is by far the dominant aggregator on Solana, routing the majority of all DEX volume. It supports limit orders, DCA (dollar-cost averaging), perpetual trading, and token launches (via its launchpad). Jupiter’s routing engine considers direct swaps, multi-hop routes (e.g., SOL → USDC → target token), and split routes across pools. Most Solana trading bots use Jupiter’s API under the hood.
When you request a swap, the aggregator’s routing engine simulates hundreds of possible paths across all integrated liquidity sources. It factors in pool depth, fees, price impact, and slippage to find the combination that gives you the most output tokens. For large swaps, it may split your order across 3-4 pools simultaneously to minimize price impact. The entire route executes atomically in one transaction.