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Express Swap

InterSwap is introducing “Express Swap”, a remarkable near instant swap feature that enables cross-chain swap transactions within seconds on its platform.

The underlying tech stack for this implementation is Axelar Intents (Express Service). This is an extension and specialized version of Axelar’s General Message Passing (GMP). To get an in-depth understanding of GMP and how it works, please refer here.

Benefits of Express Swap​

  1. Reduced latency: This drastically reduces the time required for cross-chain interactions, thereby, enhancing user experience, and operational efficiency
  2. Increased accessibility: This feature in particular is very effective that requires near instant availability of assets viz. DeFi, Gaming, standby P2P payment settlements, etc.

How does it work?​

A standard message can take several minutes for the Axelar network to fully approve the message and pass it to the final destination. The express message will still go through the Axelar network, but Express Service will lend any sent tokens to the destination address while approval is happening. Once the complete approval is done, tokens are paid back to the Express service.This process can accelerate cross-chain transfers by more than ten times, and in extreme cases, even up to a hundred times. The crucial part of Express service is complete trust between the privileged protocol and Axelar.

An Alternative way of visualizing Express Swap is thinking of it as a loan service. Funds on the destination chain are “loaned out” to the app while the transaction is still being finalized on the source chain. Once the transaction is finalized on the source chain and goes through the Axelar network, the funds that are sent through the Axelar network are used to pay back the Express Relayer on the destination chain which loaned out the funds.

Fees​

Express transactions require an additional fee per call alongside existing GMP fees. This extra fee acts as insurance for the Express relayer for assuming the risk of an Express transaction. If the fee is not paid, the transaction will revert to a regular non-Express GMP transaction.

Fees for GMP express include all of the same fees as callContractWithToken(), plus:

  • an Express Fee that covers relayer/reorg risk
  • gas used to execute the express method

For GMP Express transactions, the total refund will then be:

Refund = Gas deposit - Express fee - Gas used to execute express method - Network Base Fee
        - Execution Fee - approximate gas to process the refund

Overall, InterSwap Express Swap is a great enabler for small-mid sized instant cross-chain swap needs as it bypasses the regular transaction time and executes the transaction within seconds but comes with a slight premium fee. If transaction time is not a barrier then a regular GMP can be availed in the form of general swap.