In crypto, a trading layer facilitates the exchange of assets (e.g., tokens, NFTs) while interacting with underlying infrastructure:

- **Base Layer**: Settlement (e.g., Ethereum, Solana).

- **Execution Layer**: Order matching, liquidity pools, price discovery (e.g., DEXs like Uniswap, order-book exchanges like dYdX).

- **Aggregation Layer**: Optimizing trade routing across venues (e.g., 1inch, MetaMask Swap).