Source chains
Settlement is what you configure per flow, so the same chains can receive on either side: a payer on one chain can pay a merchant settling on another.
Testnets
Testnet flows are supported only when the source is a connected wallet. Exchange accounts and deposit addresses are not supported on testnets. Testnet flows always route through a swap or bridge provider: direct same-token, same-chain transfers are not supported. The payer’s token must differ from the settlement token, or be the same token on a different chain (for example, USDC on Base Sepolia settling USDC on Arbitrum Sepolia). All testnet chains usechainName: "EVM".
Supported token pairs are ETH to ETH, WETH to WETH, and USDC to USDC across these chains:
Use these
chainId and tokenAddress values when attaching the source and requesting a quote, and in settlementConfig.settlements when creating the flow. See the Fireblocks Flow API guide for where each field goes.
Next
Settlements
What you receive, on which chain, and where it lands.
Connections
The wallet, exchange account, or address on either side of a flow.