Circle Bridge Kit 1.15.2 enables source-paid fees

Circle Bridge Kit 1.15.2 allows users to pay Fast Transfer and Forwarding Service fees from the source chain. The recipient then receives the full USDC amount specified by the sender instead of an amount reduced by fees.

The configuration requires `feePayment: ‘source’` and `useForwarder: true`. Before bridging, developers must call `kit.estimate` with the source and destination chains, recipient address, transfer amount and fee settings. The response includes the expected destination amount, total fee, total source-chain debit, a signed quote and its expiry information.

The same transfer parameters and the unchanged quote are then passed to `kit.bridge`. For a transfer of 100 USDC, the estimate can show `amountReceived` of 100 USDC while `totalDebit` includes the additional source-chain fee. The source wallet must hold and approve the total debit and pay native gas fees for the approval and burn transactions.

The quote is signed data that Bridge Kit treats as opaque. It can expire at a specified time or source-chain block height. The SDK rejects invalid, mismatched or expired quotes instead of replacing them. If a quote expires, the user must request a new estimate.

Circle’s documentation lists Avalanche, Polygon PoS, Sei and XDC, along with their testnets, as source chains that support Standard Transfer rather than Fast Transfer for this fee configuration. Developers using source-paid fees on those networks must set `transferSpeed` to `SLOW`. The default `FAST` setting can result in a Quote API error stating that pre-finality service is unavailable.

The source-paid configuration does not support `customFee`. Developers that need to collect a separate fee must use destination-paid fees or handle the fee outside the bridge flow. Source-paid transfers also require the Forwarding Service, which retrieves the attestation and submits the destination mint without requiring a transaction from the recipient.

The package uses `depositForBurnWithFees` and, when forwarding hook data is used, `depositForBurnWithHookAndFees`. These calls use the signed Fee Service quote instead of the `maxFee` and `minFinalityThreshold` parameters used in a standard manual CCTP burn.

Circle published Bridge Kit 1.15.2 on Sept. 30, 2026. The package requires Node.js 20 or later, and its receive-exact fee types have been available since version 1.14.0. The npm `BridgeKit` class exposes `kit.estimate` and `kit.bridge`. The `estimateBridge` method used in some Arc App Kit tutorials is not present in version 1.15.2.

An Arc documentation example shows a 1 USDC Sepolia-to-Arc Testnet transfer with a total fee of 0.076527 USDC and a total source debit of 1.076527 USDC. Those figures are documentation examples, not a live quote. No live Fee Service quote was obtained because the required Fee Service and adapter credentials were unavailable. Production applications must request a current quote for each route before displaying or confirming a transfer.