Same-chain swaps

When src_chain equals dst_chain, Apsis quotes a swap instead of a bridge. There is no destination leg, no relayer, and no inventory involved: the router swaps through an allowlisted aggregator and pays the recipient in the same transaction. Same-chain swaps are EVM-only; on Solana the pair is rejected with swap quotes unsupported on destination chain. GetQuote returns the same_chain_swap case of the response, and PreviewQuote sets same_chain_swap: true.

import { isSameChainSwap, quoteOf } from "<SDK_PACKAGE>";

const response = await apsis.getQuote({ ...request, srcChain: "arbitrum", dstChain: "arbitrum" });
const sameChain = isSameChainSwap(response);
const quote = quoteOf(response);

What differs from a bridge

	Cross-chain	Same-chain
Settlement	Destination transaction by an executor	Inside the deposit transaction
Spread component	`bps_spread`	`same_chain_swap_fee`
Gas fees in the quote	`dst_fulfill_gas`, `src_refund_gas`	none
Gas drop	Supported	Always zero
Gasless	Supported	Not available
`bridge_token_src`, `bridge_token_dst`	The assets moved between chains	Both equal to `dst_token`

Quoting a pair where src_token and dst_token are the same token on the same chain is rejected as unsupported pair. There is nothing to do.

Executing it

Same-chain swaps use swapAndForward on the router, which swaps and forwards to the recipient in one call, and emits SameChainSwap.

function swapAndForward(
    bytes32 quoteHash,
    address srcToken,
    uint256 amountIn,
    address aggregator,
    bytes calldata swapData,
    address dstToken,
    uint256 minAmountOut,
    uint256 amountOut,
    uint16 referrerBps,
    address recipient
) external payable;

Build the arguments from the quote:

Argument	Source
`quoteHash`	`quote.quote_hash`
`srcToken`, `amountIn`	`order_params.src_token`, `order_params.amount_in`
`aggregator`, `swapData`	`GetSwapInstructions` on the quote hash, `payload.evm`
`dstToken`	`order_params.dst_token`
`minAmountOut`	`order_params.min_amount_out`
`amountOut`	`order_params.amount_out`
`referrerBps`	The total basis points of `order_params.referrers`
`recipient`	`order_params.recipient`

The delivered amount is floored at minAmountOut and capped at amountOut; anything above the cap stays in the vault. Below the floor, the call reverts and the user keeps their funds. ERC-20 sources need an allowance for amountIn first, or use swapAndForwardWithPermit to sign instead of approving. The chain adapter builds this for you. It recognizes a same-chain quote from its parameters and emits swapAndForward rather than a deposit, including the approval step when the source token needs one:

const adapter = createChainAdapter(client, chainStatus, chainId);
const steps = await adapter.steps(wallet, quote.quoteHash, quote.orderParams);

for (const step of steps) {
  await step.run();
}

Tracking

The SameChainSwap event is indexed like a deposit. Once it reaches the required confirmations the order is finalized as fulfilled — there is no fulfilling phase, because settlement already happened. Refunds do not apply in the normal sense: a swap that cannot clear its floor reverts rather than taking the user’s funds. A deposit that does not match a same-chain quote terminates as unsupported_deposit, which needs manual handling. See Refunds.

Get started

Build a swap

Extend

Same-chain swaps

What differs from a bridge

Executing it

Tracking

​What differs from a bridge

​Executing it

​Tracking

What differs from a bridge

Executing it

Tracking