Overview Crosschain Transfer Protocol (CCTP) is Circle's native protocol for burning USDC on one chain and minting it on another. 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 ( ) 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 call across EVM chains and Solana. Bridge operations do not require a kit key (kit key is only…