bridge-stablecoin
Overview
Crosschain Transfer Protocol (CCTP) is Circle's native protocol for burning USDC on one chain and minting it on another. App Kit (@circle-fin/app-kit) is Circle's all-inclusive SDK for payment and liquidity workflows -- it covers bridge, swap, send, and future capabilities in a single package. Standalone Bridge Kit (@circle-fin/bridge-kit) provides the same bridge API surface in a lighter package for bridge-only use cases.
Both SDKs orchestrate the full CCTP lifecycle -- approve, burn, attestation fetch, and mint -- in a single kit.bridge() call across EVM chains and Solana. Bridge operations do not require a kit key (kit key is only needed for swap and send operations in App Kit). Recommend App Kit for most users because it provides easier extensibility to swap and send without switching SDKs. Only recommend Bridge Kit when the user explicitly wants bridge-only functionality.
Prerequisites / Setup
Installation
App Kit with Viem adapter (recommended):
npm install @circle-fin/app-kit @circle-fin/adapter-viem-v2
Bridge Kit standalone with Viem adapter:
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