trader.xyz

Swap SDK by Trader.xyz is a developer-focused library designed to simplify the integration of NFT and token swap capabilities into Ethereum and EVM-compatible applications. It leverages the 0x Protocol v4, which is currently the most gas-efficient and cost-effective method for swapping NFTs on Ethereum and other supported chains. The SDK supports ERC721 and ERC1155 NFTs swapping with ERC20 tokens, enabling developers to build wallets, marketplaces, or peer-to-peer swap apps with minimal effort. Swap SDK handles order creation, signing, approval, and fulfillment, allowing developers to focus on building user interfaces.

The SDK supports both on-chain and off-chain order listings, providing flexibility in how trades are managed and executed. It also offers a managed orderbook service, removing the need for developers to build their own off-chain order persistence infrastructure. Swap SDK's integration with 0x v4 protocol results in significantly lower gas fees compared to popular NFT marketplaces, with benchmarks showing up to 40% savings versus OpenSea and others. Supported chains include Ethereum Mainnet, Polygon, Optimism, Binance Smart Chain, Fantom, Celo, and Ropsten testnet, with Arbitrum support forthcoming.

Developers can get started quickly by installing the SDK via npm or yarn, then initializing the NftSwapV4 instance with a provider, signer, and chain ID. The SDK provides straightforward methods to approve tokens, build and sign orders, and fill trades. Comprehensive documentation includes examples for common swap scenarios, batch buying NFTs, royalty and fee configurations, and more. Swap SDK is open source, funded by a 0x DAO grant, and actively maintained to support evolving NFT swap use cases.