# Gasless transactions

**Gasless** mode allows the users of the **Eywa** ecosystem to conveniently perform cross-chain operations by paying an entire commission for its execution in a source chain. **Gasless** greatly simplifies an interaction with the cross-chain products of the **Eywa** ecosystem. It vanishes the necessity for the users to pay commissions in many assets and allows them to choose in which asset of a source network to pay the commission.

Currently, the user can pay a cross-chain transaction fee with the native asset of the source network.

We plan to implement the following functionality in the future, user can pay a cross-chain transaction fee uses:

* With the token sent from the body of the transaction;
* In **Eywa** tokens;

### **Why is Gasless mode needed?**

The cross-chain transaction causes a sequential code execution within multiple blockchains. As any interaction with the blockchain is paid with gas, in order to successfully complete the cross-chain transaction, it is necessary to pay for its execution in each of the networks.

{% hint style="info" %}
**Consider an example of the cross-chain transaction:** you exchange the assets from the **Ethereum** network for the assets from the **BNB Chain** using a cross-chain pool located in **Fantom**. The given exchange transaction simultaneously affects three blockchains: **Ethereum → Hub chain → BNB Chain**. To successfully complete the transaction, gas must be successively paid in **ETH, FTM** and **BNB** assets. From the user's point of view, this would mean that he / she needs to sign three transactions in different blockchains. It is time consuming and inconvenient.
{% endhint %}

The **Gasless** infrastructure, created by the **Eywa** team, takes over the job of paying for the user's cross-chain transaction in different blockchains. By using **Gasless**, the user only needs to pay for the transaction once in the source network via one of the proposed ways. Further, the cross-chain transaction will be completely executed without his / her participation.

### Transaction payment methods

When using the **Eywa** products, you can choose one of the following payment methods for the cross-chain transactions:

1. **Payment for the cross-chain transaction with the native asset of the source network.** In this case, the user will be offered to pay for the cross-chain transaction in the native asset of the source network;
2. **Payment in the token sent from the body of the transaction.** In this case, the user will be proposed to pay for the cross-chain transaction in the token being sent. The commission will be included to the body of the transaction that the user will be signing;
3. **Payment for the cross-chain transactions in the Eywa tokens.** In this case, the user will be prompted to pay for the cross-chain transaction in the **Eywa** tokens. The commission will be included to the body of the transaction that the user will be signing. Payment in the **Eywa** tokens is the cheapest way to pay for the transaction and saves the user up to 10-20% of the commission.

{% hint style="info" %}
The easiest way to perceive **Gasless** is as follows: you pay to the **Gasless** infrastructure in any way convenient for you and **Gasless** guarantees the successful execution of the cross-chain transaction on your behalf.
{% endhint %}

### **Payment for the cross-chain transaction with the native asset of the source network**

The transaction payment process is implemented as follows:

1. **Sending the meta-transaction to the Eywa Pusher.** The user sends the signed meta-transaction to the **Eywa Pusher**. The meta-transaction comprises the description of the cross-chain transaction that the user wants to perform. The meta-transaction does not require the gas payment, as it is a regular Internet request and is not executed on any blockchain.
2. **Estimating the price of the cross-chain transaction on the Eywa Pusher.** The **Eywa** server estimates an amount of gas each network will need to successfully complete the cross-chain transaction. Based on the given information, the transaction price in the native asset of the network and a deadline until which the determined price is valid are being calculated.
3. **Signing the cross-chain transaction by the user.** The user is offered to sign the cross-chain transaction, which already includes the commission calculated in the **Step 2.**
4. **Executing the cross-chain transaction by the Gasless infrastructure.** After the user signs the cross-chain transaction, the commission is sent to the smart contract of the **Gasless** infrastructure. Subsequently, the **Gasless** infrastructure performs the cross-chain transaction on behalf of the user.

{% hint style="info" %}
If the user does not signed the proposed transaction before the specified deadline, the **Gasless** infrastructure will not perform the cross-chain transaction at the previously proposed price. In this case, the user needs to send the meta-transaction again to get the actual price.
{% endhint %}