What is the difference between USDT <> USDC (Stablecoin) swaps and swaps involving other token?

Swaps between USDT<>USDC are done with our own liquidity. For all other swaps we rely on selected aggregators.

Reliability and Failure Handling

Swaps with our own liquidity (USDC<>USDT) have no real failure path - if there are issues on the destination chain, the system will retry the withdrawal indefinitely until it succeeds, so these transactions always go through eventually. In contrast, aggregator swaps can fail due to market volatility and other factors. When aggregator swaps fail, the system retries a few times and then automatically refunds the user on the source chain with a SWAP_FAILED_REFUNDED state.

Speed and Stability

Own liquidity swaps provide better stability and conversion rates since they don't rely on third-party services. The system removes the aggregator step, improving both stability and conversion rates for clients.

Transaction Size Capacity

Own liquidity allows support for very large transaction sizes (up to several million per transaction) and enables products like 1:1 stablecoin transfers with no slippage.

Implementation Differences

When getting a quote, aggregator swaps return an additional field isAtomicSwap: true indicating they use external aggregators and require calling the swap function on the SameChainSwaps contract. Own liquidity swaps return quotes with no additional field and use the regular bridge contract flow.

Pricing and Fees

Own liquidity swaps can offer better rates since there's no third-party aggregator fee, and the system can provide consistent 1:1 stablecoin swaps within certain exchange rate bands. Aggregator swaps follow standard market rates with potential slippage.