Bankr X402 SDK Transaction Builder

If you're building blockchain interactions into Claude workflows, this handles the transaction construction part across common operations like ERC20 transfers, NFT purchases, wrapping ETH, and cross-chain bridges. It supports the major use cases you'd expect: sending tokens, minting NFTs from Manifold or SeaDrop contracts, and bridging between chains. The prompt interface is straightforward, you just tell it what you want in plain language and it builds the transaction object. Useful if you're prototyping DeFi tools or building agents that need to interact with Ethereum and L2s without writing transaction logic from scratch every time. The repo has 78 stars, so there's at least some community validation here.

GitHub stars: 80
last updated: Aug 21, 2026

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Install

$ npx -y skills add bankrbot/claude-plugins --skill 'Bankr x402 SDK - Transaction Builder' --agent claude-code

Installs into .claude/skills of the current project.

Files

SDK Transaction Builder

Build blockchain transactions for transfers, NFTs, bridges, and DeFi operations.

Transaction Types

Type	Description	Example Prompt
`transfer_erc20`	Send ERC20 tokens	"Send 100 USDC to 0x..."
`transfer_eth`	Send native ETH	"Send 0.1 ETH to 0x..."
`convert_eth_to_weth`	Wrap ETH	"Wrap 0.5 ETH"
`convert_weth_to_eth`	Unwrap WETH	"Unwrap 1 WETH"
`transfer_nft`	Send NFT	"Transfer my NFT #123 to 0x..."
`buy_nft`	Purchase NFT	"Buy the cheapest Pudgy Penguin"
`mint_manifold_nft`	Mint from Manifold	"Mint from Manifold at 0x..."
`mint_seadrop_nft`	Mint from SeaDrop	"Mint from SeaDrop at 0x..."
`swapCrossChain`	Bridge tokens	"Bridge 100 USDC from Ethereum to Base"

Prompt Patterns

# Transfers
"Send 100 USDC to 0x742d35..."
"Transfer 0.5 ETH to vitalik.eth"
"Send 50 USDC to 0x123... on Base"

# ETH/WETH
"Wrap 0.5 ETH to WETH"
"Unwrap 1 WETH to ETH"

# NFTs
"Transfer my Pudgy Penguin #1234 to 0x..."
"Buy the cheapest Pudgy Penguin on OpenSea"
"Mint NFT from Manifold contract 0x..."

SKILL.md on GitHub