> ## Documentation Index
> Fetch the complete documentation index at: https://docs.optimism.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Bridging Your Standard ERC-20 Token Using the Standard Bridge

> Learn how to bridge your standard ERC-20 token using the standard bridge.

In this tutorial you'll learn how to bridge a standard ERC-20 token from Ethereum to an OP Stack chain using the Standard Bridge system.
This tutorial is meant for developers who already have an existing ERC-20 token on Ethereum and want to create a bridged representation of that token on layer 2.

This tutorial explains how to use the [`OptimismMintableERC20Factory`](https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/src/universal/OptimismMintableERC20Factory.sol) to deploy a standardized ERC-20 token on layer 2.
Tokens created by this factory contract are compatible with the Standard Bridge system and include basic logic for deposits, transfers, and withdrawals.
If you want to include specialized logic within your L2 token, see the tutorial on [Bridging Your Custom ERC-20 Token Using the Standard Bridge](./standard-bridge-custom-token) instead.

<Info>
  The Standard Bridge **does not** support [**fee on transfer tokens**](https://github.com/d-xo/weird-erc20#fee-on-transfer) or [**rebasing tokens**](https://github.com/d-xo/weird-erc20#balance-modifications-outside-of-transfers-rebasingairdrops) because they can cause bridge accounting errors.
</Info>

## About OptimismMintableERC20s

The Standard Bridge system requires that L2 representations of L1 tokens implement the [`IOptimismMintableERC20`](https://github.com/ethereum-optimism/optimism/blob/v1.12.0/packages/contracts-bedrock/src/universal/OptimismMintableERC20.sol) interface.
This interface is a superset of the standard ERC-20 interface and includes functions that allow the bridge to properly verify deposits/withdrawals and mint/burn tokens as needed.
Your L2 token contract must implement this interface in order to be bridged using the Standard Bridge system.
This tutorial will show you how to use the [`OptimismMintableERC20Factory`](https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/src/universal/OptimismMintableERC20Factory.sol) to create a basic standardized ERC-20 token on layer 2.

## Dependencies

* [cast](https://book.getfoundry.sh/getting-started/installation)

## Get ETH on Sepolia and OP Sepolia

This tutorial explains how to create a bridged ERC-20 token on OP Sepolia.
You will need to get some ETH on both of these testnets.

<Info>
  You can use [this faucet](https://sepoliafaucet.com) to get ETH on Sepolia.
  You can use the [Superchain Faucet](https://console.optimism.io/faucet?utm_source=op-docs\&utm_medium=docs) to get ETH on OP Sepolia.
</Info>

## Get an L1 ERC-20 token address

You will need an L1 ERC-20 token for this tutorial.
If you already have an L1 ERC-20 token deployed on Sepolia, you can skip this step.
Otherwise, you can use the testing token located at [`0x5589BB8228C07c4e15558875fAf2B859f678d129`](https://sepolia.etherscan.io/address/0x5589BB8228C07c4e15558875fAf2B859f678d129) that includes a `faucet()` function that can be used to mint tokens.

## Create an L2 ERC-20 Token

Once you have an L1 ERC-20 token, you can use the [`OptimismMintableERC20Factory`](https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/src/universal/OptimismMintableERC20Factory.sol) to create a corresponding L2 ERC-20 token on OP Sepolia.
All tokens created by the factory implement the `IOptimismMintableERC20` interface and are compatible with the Standard Bridge system.

<Steps>
  <Step title="Add a private key to your environment">
    You'll need a private key in order to sign transactions.
    Set your private key as an environment variable with the `export` command.
    Make sure this private key corresponds to an address that has ETH on OP Sepolia.

    ```bash theme={null}
    export TUTORIAL_PRIVATE_KEY=0x...
    ```
  </Step>

  <Step title="Add an OP Sepolia RPC URL to your environment">
    You'll need an RPC URL in order to connect to OP Sepolia.
    Set your RPC URL as an environment variable with the `export` command.

    ```bash theme={null}
    export TUTORIAL_RPC_URL=https://sepolia.optimism.io
    ```
  </Step>

  <Step title="Add your L1 ERC-20 token address to your environment">
    You'll need to know the address of your L1 ERC-20 token in order to create a bridged representation of it on OP Sepolia.
    Set your L1 ERC-20 token address as an environment variable with the `export` command.

    ```bash theme={null}
    # Replace this with your L1 ERC-20 token if not using the testing token!
    export TUTORIAL_L1_ERC20_ADDRESS=0x5589BB8228C07c4e15558875fAf2B859f678d129
    ```
  </Step>

  <Step title="Deploy your L2 ERC-20 token">
    You can now deploy your L2 ERC-20 token using the [`OptimismMintableERC20Factory`](https://github.com/ethereum-optimism/optimism/blob/develop/packages/contracts-bedrock/src/universal/OptimismMintableERC20Factory.sol).
    Use the `cast` command to trigger the deployment function on the factory contract.
    This example command creates a token with the name "My Standard Demo Token" and the symbol "L2TKN".
    The resulting L2 ERC-20 token address is printed to the console.

    ```bash theme={null}
    cast send 0x4200000000000000000000000000000000000012 "createOptimismMintableERC20(address,string,string)" $TUTORIAL_L1_ERC20_ADDRESS "My Standard Demo Token" "L2TKN" --private-key $TUTORIAL_PRIVATE_KEY --rpc-url $TUTORIAL_RPC_URL --json | jq -r '.logs[0].topics[2]' | cast parse-bytes32-address
    ```
  </Step>
</Steps>

## Bridge some tokens

Now that you have an L2 ERC-20 token, you can bridge some tokens from L1 to L2.
Check out the tutorial on [Bridging ERC-20 tokens with viem](./cross-dom-bridge-erc20) to learn how to bridge your L1 ERC-20 to L2s using viem.

## Add to the Superchain Token List

The [Superchain Token List](https://github.com/ethereum-optimism/ethereum-optimism.github.io#readme) is a common list of tokens deployed on chains within the Optimism Superchain.
This list is used by services like the [Superchain Bridges UI](https://app.optimism.io/bridge?utm_source=op-docs\&utm_medium=docs).
If you want your OP Mainnet token to be included in this list, take a look at the [review process and merge criteria](https://github.com/ethereum-optimism/ethereum-optimism.github.io#review-process-and-merge-criteria).