> For the complete documentation index, see [llms.txt](https://btcfi.gitbook.io/whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://btcfi.gitbook.io/whitepaper/runesfi/runes-evm-bridge/bridging-process.md).

# Bridging Process

Token Transfer Process

RunesBridge enables the transfer of Runes tokens to ERC-20 and allows users to return them to the native Bitcoin chain by transferring ERC-20 to Runes.

#### Runes to ERC-20 Transfer <a href="#brc-20-to-erc-20-transfer" id="brc-20-to-erc-20-transfer"></a>

Below are the steps to migrate Runes tokens to Ethereum.

1. The user initiates the transfer request by specifying the amount of Runes tokens.

<figure><img src="/files/hw3asV4S6hprEoX4lEiv" alt=""><figcaption></figcaption></figure>

2. We need to inscribe the custom 'transfer' inscription. It is backwards compatible and supported.
3. Once inscribed, we need to transfer it to the RunesFI wallet.
4. The validators will wait 2-3 blocks to get mine for security and to avoid double-spending. After about 30 minutes, you can close the tab and return later.
5. We will see the claim button once the entry gets verified on the Bitcoin chain.
6. The transaction will be sent to the RunesFi smart contract after clicking the claim button.
7. Viola! Wrapped ERC-20 tokens will be sent to your wallet. Like any other ERC-20 tokens, you can trade or use them freely.

Note: It is crucial to ensure that the wallet used for the claim matches the one specified in the transfer inscription.

#### ERC-20 to Runes Transfer: <a href="#erc-20-to-brc-20-transfer" id="erc-20-to-brc-20-transfer"></a>

1. The user initiates the transfer by specifying the amount of ERC-20 tokens.
2. RunesFi validates the user's token balance and verifies the availability of the requested amount.
3. The user sends the transaction on the ETH blockchain to burn Runes tokens and initiates minting Runes tokens.
4. RunesFi waits for 15 confirmation blocks on the Ethereum chain (approximately 3-4 minutes) to verify and secure transactions.
5. Once the blocks are confirmed, the 'transfer' inscription is sent to the designated address (mentioned during the smart contract call), initiating the transfer process of Runes tokens to the user's wallet.

Note: The inscription transfer process requires RunesBridge to bear gas fees. Hence, 0.01E fees are charged to the user when sending ERC-20 tokens on the ETH mainnet.


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