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

# Bridging

Transfer assets between Ethereum and [Immutable Chain](/docs/products/immutable-chain/overview) using the canonical bridge or third-party solutions.

<CardGroup cols={2}>
  <Card title="Bridge Contracts" icon="github" href="https://github.com/immutable/zkevm-bridge-contracts">
    View the bridge contract source code
  </Card>

  <Card title="Audit Reports" icon="shield-check" href="https://github.com/immutable/zkevm-bridge-contracts/tree/main/audits">
    Trail of Bits audit and Perimeter fuzzing reports
  </Card>
</CardGroup>

## Bridge Options

| Bridge                                    | Type              | Speed     | Best For                        |
| ----------------------------------------- | ----------------- | --------- | ------------------------------- |
| **[Canonical Bridge](#canonical-bridge)** | Native (Axelar)   | 15-30 min | Large amounts, highest security |
| **[LayerSwap](https://layerswap.io)**     | Liquidity Network | Minutes   | Fast transfers                  |
| **[Squid](https://squidrouter.com)**      | Aggregator        | Minutes   | Multi-chain routing             |

<Info>
  The canonical bridge currently uses [Axelar](https://axelar.network/) for cross-chain messaging, with plans to add ZK proofs in the future for enhanced security.
</Info>

## Bridge UIs

<CardGroup cols={2}>
  <Card title="Immutable Play" icon="gamepad" href="https://play.immutable.com">
    Best interface for [Passport](/docs/products/passport/overview) wallets
  </Card>

  <Card title="Toolkit" icon="wrench" href="https://toolkit.immutable.com/ethereum-bridge/">
    Canonical bridge for advanced users
  </Card>
</CardGroup>

## Canonical Bridge

The canonical bridge enables secure asset transfers between Ethereum (L1) and Immutable Chain (L2).

### Supported Assets

| Asset                 | L1 → L2 | L2 → L1 |
| --------------------- | ------- | ------- |
| **ETH**               | ✅       | ✅       |
| **IMX**               | ✅       | ✅       |
| **USDC**              | ✅       | ✅       |
| **USDT**              | ✅       | ✅       |
| **wBTC**              | ✅       | ✅       |
| **any mapped ERC-20** | ✅       | ✅       |

### How It Works

**Deposit (L1 → L2)**: \~15-30 minutes

1. Call the bridge contract on Ethereum with the asset and destination
2. Wait for L1 confirmation and Axelar relay
3. Assets appear in your L2 wallet

**Withdrawal (L2 → L1)**: Up to 24 hours (see [Flow Rate Parameters](#flow-rate-parameters))

1. Call the bridge contract on Immutable Chain
2. Wait for message relay
3. Claim on Ethereum

### Flow Rate Parameters

The bridge implements safety mechanisms to protect against exploits:

| Token                                                                         | Flow-Rate Capacity (4-Hour Window) | Large Withdrawal Threshold |
| ----------------------------------------------------------------------------- | ---------------------------------- | -------------------------- |
| ETH                                                                           | 148                                | 29.60                      |
| [IMX](https://etherscan.io/token/0xF57e7e7C23978C3cAEC3C3548E3D615c346e79fF)  | 539,052                            | 107,230                    |
| [USDC](https://etherscan.io/token/0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) | 372,000                            | 74,000                     |
| [USDT](https://etherscan.io/token/0xdAC17F958D2ee523a2206206994597C13D831ec7) | 372,000                            | 74,000                     |
| [wBTC](https://etherscan.io/token/0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599) | 3.37                               | 0.67                       |
| [GODS](https://etherscan.io/token/0xccC8cb5229B0ac8069C51fd58367Fd1e622aFD97) | 2,310,559                          | 459,627                    |
| [GOG](https://etherscan.io/token/0x9AB7bb7FdC60f4357ECFef43986818A2A3569c62)  | 9,386,828                          | 1,867,272                  |

<Warning>
  **Large withdrawals** exceeding the threshold are queued for 24 hours. If total withdrawals in a 4-hour window exceed the flow rate capacity, all withdrawals are queued until manually reviewed.
</Warning>

## Bridge Contract Addresses

### Ethereum (L1)

| Contract          | Mainnet                                                                                                                 | Testnet (Sepolia)                                                                                                               |
| ----------------- | ----------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------- |
| **Bridge Proxy**  | [`0xBa5E35E26Ae59c7aea6F029B68c6460De2d13eB6`](https://etherscan.io/address/0xBa5E35E26Ae59c7aea6F029B68c6460De2d13eB6) | [`0x0D3C59c779Fd552C27b23F723E80246c840100F5`](https://sepolia.etherscan.io/address/0x0D3C59c779Fd552C27b23F723E80246c840100F5) |
| **Adaptor Proxy** | [`0x4f49B53928A71E553bB1B0F66a5BcB54Fd4E8932`](https://etherscan.io/address/0x4f49B53928A71E553bB1B0F66a5BcB54Fd4E8932) | [`0x6328Ac88ba8D466a0F551FC7C42C61d1aC7f92ab`](https://sepolia.etherscan.io/address/0x6328Ac88ba8D466a0F551FC7C42C61d1aC7f92ab) |

### Immutable Chain (L2)

| Contract          | Mainnet                                                                                                                           | Testnet                                                                                                                                   |
| ----------------- | --------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| **Bridge Proxy**  | [`0xBa5E35E26Ae59c7aea6F029B68c6460De2d13eB6`](https://explorer.immutable.com/address/0xBa5E35E26Ae59c7aea6F029B68c6460De2d13eB6) | [`0x0D3C59c779Fd552C27b23F723E80246c840100F5`](https://explorer.testnet.immutable.com/address/0x0D3C59c779Fd552C27b23F723E80246c840100F5) |
| **Adaptor Proxy** | [`0x4f49B53928A71E553bB1B0F66a5BcB54Fd4E8932`](https://explorer.immutable.com/address/0x4f49B53928A71E553bB1B0F66a5BcB54Fd4E8932) | [`0x6328Ac88ba8D466a0F551FC7C42C61d1aC7f92ab`](https://explorer.testnet.immutable.com/address/0x6328Ac88ba8D466a0F551FC7C42C61d1aC7f92ab) |

### Token Addresses (L2)

| Token           | Mainnet                                                                                                                           | Testnet                                                                                                                                   |
| --------------- | --------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| **Wrapped ETH** | [`0x52a6c53869ce09a731cd772f245b97a4401d3348`](https://explorer.immutable.com/address/0x52a6c53869ce09a731cd772f245b97a4401d3348) | [`0xe9E96d1aad82562b7588F03f49aD34186f996478`](https://explorer.testnet.immutable.com/address/0xe9E96d1aad82562b7588F03f49aD34186f996478) |
| **Wrapped IMX** | [`0x3a0c2ba54d6cbd3121f01b96dfd20e99d1696c9d`](https://explorer.immutable.com/address/0x3a0c2ba54d6cbd3121f01b96dfd20e99d1696c9d) | [`0x1CcCa691501174B4A623CeDA58cC8f1a76dc3439`](https://explorer.testnet.immutable.com/address/0x1CcCa691501174B4A623CeDA58cC8f1a76dc3439) |
| **USDC**        | [`0x6de8aCC0D406837030CE4dd28e7c08C5a96a30d2`](https://explorer.immutable.com/address/0x6de8aCC0D406837030CE4dd28e7c08C5a96a30d2) | [`0x3B2d8A1931736Fc321C24864BceEe981B11c3c57`](https://explorer.testnet.immutable.com/address/0x3B2d8A1931736Fc321C24864BceEe981B11c3c57) |
| **USDT**        | [`0x68bcc7F1190AF20e7b572BCfb431c3Ac10A936Ab`](https://explorer.immutable.com/address/0x68bcc7F1190AF20e7b572BCfb431c3Ac10A936Ab) | TBA                                                                                                                                       |
| **Wrapped BTC** | [`0x235F9A2Dc29E51cE7D103bcC5Dfb4F5c9c3371De`](https://explorer.immutable.com/address/0x235F9A2Dc29E51cE7D103bcC5Dfb4F5c9c3371De) | TBA                                                                                                                                       |
| **GODS**        | [`0xE0e0981D19eF2E0a57Cc48CA60D9454eD2D53fEB`](https://explorer.immutable.com/address/0xE0e0981D19eF2E0a57Cc48CA60D9454eD2D53fEB) | TBA                                                                                                                                       |
| **GOG**         | [`0xb00ed913aAFf8280C17BfF33CcE82fE6D79e85e8`](https://explorer.immutable.com/address/0xb00ed913aAFf8280C17BfF33CcE82fE6D79e85e8) | TBA                                                                                                                                       |

## Querying Flow Rates

You can query flow rate parameters directly from the L1 bridge contract:

* `flowRateBuckets(tokenAddress)` - Returns bucket capacity and refill rate
* `largeTransferThreshold(tokenAddress)` - Returns the large withdrawal threshold

<Card title="Manual Bridging Guide" icon="code" href="https://github.com/immutable/zkevm-bridge-contracts/blob/main/docs/manual-bridging.md">
  For programmatic bridging, see the manual bridging documentation
</Card>

## Next Steps

<CardGroup cols={3}>
  <Card title="Native Token" icon="coins" href="/docs/products/immutable-chain/native-token">
    Understand IMX token usage
  </Card>

  <Card title="Passport" icon="id-card" href="/docs/products/passport/overview">
    Set up wallet integration
  </Card>

  <Card title="Differences from Ethereum" icon="code-compare" href="/docs/products/immutable-chain/differences-from-ethereum">
    Review chain differences
  </Card>
</CardGroup>