unify-balance

Build unified cross-chain USDC balance management with Circle Unified Balance Kit SDK via App Kit (`@circle-fin/app-kit`) or standalone (`@circle-fin/unified-balance-kit`). Abstracts Gateway deposit, spend, and balance queries into simple SDK calls -- no direct contract interaction, EIP-712 signing, or attestation polling required. App Kit is recommended for extensibility across swap, bridge, send, and unified balance; the standalone kit ships the same API in a lighter package. Neither requires a kit key. Supports EVM chains and Solana via adapter packages (Viem, Solana, Circle Wallets). Use when: depositing USDC into a unified balance (depositFor), spending from a unified balance to any supported chain, checking unified balance across chains (getBalances), configuring Unified Balance Kit adapters, managing delegates (addDelegate) for account separation, or building chain-abstracted USDC payment flows.