Slippage Tolerance Distribution in Cross-Chain Swaps

Generally, a cross-chain swap consists of three transactions executed on the source, host, and destination chains.

There can be on-chain swaps within a cross-chain swap:

• (A) Source chain — An on-chain swap is optional and performed if the source token differs from the transit token used on the source chain.

• (B) Host chain — An on-chain swap is always performed to exchange synthetic tokens issued for the source and destination chains.

• (C) Destination chain — An on-chain swap is optional and performed if the destination token differs from the transit token used on the destination chain.

Example

Consider a swap: ETH (Ethereum) → BNB (BNB Chain) This cross-chain swap includes three on-chain swaps:

• (A) Ethereum: ETH → USDC

• (B) Symbiosis Chain: sUSDC (issued for Ethereum) → sUSDC (issued for BNB Chain)

• (C) BNB Chain: USDC → BNB

Slippage Tolerance Value

The Symbiosis API accepts slippage tolerance values ranging from 0.2% to 10%. The specified slippage tolerance value applies to the entire cross-chain swap.

The following describes how this value is divided between chains.

Let the specified slippage tolerance be Y.

Slippage Tolerance Allocation Summary

A: ✗ B: ✓ C: ✗ Swap example: USDC (Ethereum) -> USDC (BNB)	B (host): 0.2% Remaining slippage ignored
A: ✓ B: ✓ C: ✗ Swap example: ETH (Ethereum) -> USDC (BNB)	if Y/2 > 0.2% B (host): 0.2 A (source): Y − 0.2 Else B (host): Y/2 A (source): Y/2
A: ✗ B: ✓ C: ✓ Swap example: USDC (Ethereum) -> BNB (BNB)	if Y/2 > 0.2% B (host): 0.2% C (destination): Y - 0.2 Else B (host): Y/2 C (destination): Y/2
A: ✓ B: ✓ C: ✓ Swap example: ETH (Ethereum) -> BNB (BNB)	if Y/3 > 0.2% B (host): 0.2% A (source): (Y - 0.2) / 2 C (destination): (Y - 0.2) / 2 else B (host): Y / 3 A (source): Y / 3 C (destination): Y / 3

Note:

• A maximum of 0.2 % is reserved for the host-chain on-chain swap (B).

Example:

ETH (Ethereum) -> BNB (BNB), Y = 1.5%

• A (source): 0.65%

• B (host): 0.2%

• C (destination): 0.65%

Auto Slippage Mode

This feature is currently under development. Detailed parameters and calculation logic will be documented after release.

If the slippage tolerance value is not specified for a cross-chain swap, Symbiosis will apply an auto slippage mode.

In this mode, the slippage tolerance is determined dynamically based on the current on-chain market conditions and liquidity depth for each leg of the swap.