Circle Bridge Kit Adds One-Call USDC Transfers

Circle Bridge Kit 1.15.2 lets developers transfer native USDC across supported chains with one `kit.bridge` call. The TypeScript SDK combines the source-chain burn, Circle’s Iris attestation and the destination-chain mint that developers must handle separately in direct CCTP integrations.

The SDK uses Circle’s Cross-Chain Transfer Protocol v2 by default and supports applications moving USDC between selected EVM and non-EVM networks. Circle’s package listing identified version 1.15.2 as the latest release on Oct. 10, 2026. The package requires Node.js 20 or later and recorded 17,873 weekly npm downloads from Oct. 2 to Oct. 8.

Developers can install Bridge Kit with an adapter such as Circle’s Viem v2 package. They then create a wallet or browser-provider connection and set the source chain, destination chain and transfer amount. The request includes a source adapter and, for a user-controlled destination wallet, a destination adapter.

The `kit.estimate` method provides fee and gas information before a transaction is signed. `supportsRoute` checks whether a transfer route is available, while `getSupportedChains` returns supported networks. The `kit.retry` method can resume some failed or incomplete operations.

Bridge Kit uses FAST transfer mode by default. Circle describes FAST as its Fast Transfer option, with transfers on Ethereum and layer-2 networks generally taking about eight to 20 seconds. Fees vary by route, with Circle’s published examples ranging from zero to 13 basis points. Developers can select SLOW, which corresponds to Standard Transfer and is listed at zero basis points on Circle’s fee tables. Transfers through Ethereum and layer-2 networks can take about 15 to 19 minutes in that mode.

The `maxFee` setting sets the highest fee allowed during the source-chain burn. If the live fee exceeds that limit, the transaction reverts and no USDC is burned. Circle advises applications to obtain current fee data instead of using fixed values.

Bridge Kit supports Circle’s forwarder option when the sender does not control a wallet on the destination chain. With `useForwarder: true`, an application can provide a recipient address without a destination adapter. Circle’s Orbit relayer handles the attestation and destination mint. Applications that set `maxFee` manually must include the forwarder fee. If they do not, the relay may lack enough funds to complete the destination operation.

The package includes a private-key adapter for scripts and servers, as well as browser wallet providers and custom RPC settings. A private-key adapter keeps the key in the application process. Circle’s documentation supports user-controlled wallets and policy-controlled signers for applications handling real funds.

Bridge Kit supports native USDC on Circle-supported CCTP routes. It does not provide liquidity routes for arbitrary tokens or aggregate quotes across bridge protocols. Applications using unsupported assets or chains must use another bridging method or connect directly to CCTP where available.

Circle’s documentation separates Bridge Kit from direct CCTP integration. Bridge Kit combines approval, `depositForBurn`, Iris attestation polling and `receiveMessage` in an SDK workflow. Direct CCTP integration leaves those operations under the developer’s control, which supports custom burn contracts, batch transfers, independent attestation workers, unsupported routes and detailed gas accounting inside a larger transaction system.