# Gasless Swap

<figure><img src="/files/E2CFa61W1xcPJvNX7w7k" alt=""><figcaption></figcaption></figure>

Null Finance allows swaps that do not incur gas fees. Currently supported on **Ethereum, Polygon, Arbitrum, Optimism, and Base** Networks. Please check out the 0x Protocol documentation for [how gasless swaps work](https://0x.org/docs/category/gasless-api).

On networks where gasless swaps are provided, they are automatically processed as gasless swaps, and additional procedures that are different from those on other networks are required.

<figure><img src="/files/RDQMdQbwFq0D5xE63R9w" alt=""><figcaption></figcaption></figure>

### Trade Signature

Gasless swaps require a transaction signature because the contract takes the amount the user wants to swap and sends it to the contract. This process is requested on the screen below.

<figure><img src="/files/58NnIB1cD2dlmuN2mwv1" alt=""><figcaption></figcaption></figure>

Clicking the **Sign Trade** button will prompt you for a signature.

<figure><img src="/files/sbuuFViSAFLtXhiBb0Dz" alt=""><figcaption></figcaption></figure>

After confirming the signature request and signing, the screen below will appear.

<figure><img src="/files/xVqW2CqaDmSkwbvR9Nd2" alt=""><figcaption></figcaption></figure>

Once all signatures are complete, click Submit Order to proceed with the transaction. If the transaction is successful, the screen will change to Transaction Pending, and **in some cases, the signature may expire.**

There are various cases where a signature expires. For example, the price of the token fluctuates rapidly from the time the signature is completed to the moment the submit order is sent, making it impossible to complete the transaction, or the time has expired, or the signature expires due to the algorithm of the 0x Protocol. In this case, we recommend adjusting the quantity and trying again.


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