> For the complete documentation index, see [llms.txt](https://mantabridge.gitbook.io/manta-bridge-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mantabridge.gitbook.io/manta-bridge-docs/getting-started/how-it-works.md).

# how it works

Manta Bridge moves supported assets between Ethereum L1 and Manta Pacific L2. This page explains the basic flow for deposits, withdrawals, and ERC-20 approvals so you know what each wallet transaction is doing.

## Overview

Manta Pacific is a modular Ethereum L2 that uses OP Stack execution and Celestia data availability. ETH is the gas token on Manta Pacific, so you need ETH on the destination network to pay for transactions after bridging.

| Action        | Direction                       | What happens                                                                                                               |
| ------------- | ------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| Deposit       | Ethereum L1 -> Manta Pacific L2 | You submit a transaction on L1. After the bridge message is processed, the corresponding asset balance is available on L2. |
| Withdraw      | Manta Pacific L2 -> Ethereum L1 | You start the exit from L2. The withdrawal follows the rollup exit and challenge flow before funds can be finalized on L1. |
| Approve token | ERC-20 on source chain          | You authorize the bridge contract to move a specific token amount before the transfer transaction can use it.              |

Use the live [Manta Bridge](https://mantabridge.cc/) to check supported assets, current route status, and any values shown at the time you bridge.

## Deposits: L1 to L2

A deposit starts on Ethereum L1 and results in the asset appearing on Manta Pacific.

1. Connect your wallet and select Ethereum as the source network.
2. Choose the supported asset and amount you want to bridge.
3. If the asset is an ERC-20, approve the token when prompted.
4. Confirm the deposit transaction in your wallet.
5. Wait for the L1 transaction and bridge message to be processed.
6. Switch your wallet to Manta Pacific and verify the L2 balance.

For a step-by-step ETH walkthrough, see [Bridge ETH to Manta Pacific](file:///2078213/guides/bridge-eth-to-manta-pacific.md).

{% hint style="info" %}
Network fees and processing status can change with live network conditions. Always review the wallet prompt and bridge interface before confirming.
{% endhint %}

## Withdrawals: L2 to L1

Withdrawals move assets from Manta Pacific back to Ethereum L1. Because Manta Pacific is an optimistic-rollup-style L2, withdrawals follow the rollup's exit model rather than completing as a single instant transfer.

In practice, a withdrawal usually has three parts:

1. Start the withdrawal on Manta Pacific.
2. Wait for the rollup exit and challenge process required by the bridge route.
3. Complete or finalize the withdrawal on Ethereum L1 when it becomes available.

The exact timing can vary by asset, route, and network conditions. For more detail on what affects completion time, see [Bridge Time](file:///2078213/reference/bridge-time.md).

Ethereum's documentation explains how [optimistic rollups](https://ethereum.org/developers/docs/scaling/optimistic-rollups/) rely on L1 contracts, offchain execution, and challenge periods to finalize state.

## ERC-20 approvals

ETH transfers do not use ERC-20 approvals. ERC-20 tokens, such as supported stablecoins, use an allowance model: before the bridge can move the token from your wallet, you approve the bridge contract to spend up to a selected amount.

An approval is separate from the bridge transfer:

| Transaction     | Purpose                                                                                |
| --------------- | -------------------------------------------------------------------------------------- |
| Approval        | Grants the bridge contract permission to use the selected ERC-20 token amount.         |
| Bridge transfer | Sends the actual deposit or withdrawal transaction after the required approval exists. |

Before approving, check the token, spender, network, and amount shown in your wallet. For approval management and revocation guidance, see [Token Approvals](file:///2078213/guides/token-approvals.md).

For background on the token standard, see the Ethereum documentation for [ERC-20 tokens](https://ethereum.org/developers/docs/standards/tokens/erc-20/). For Manta Pacific's modular data availability layer context, see Celestia's guide to [data availability](https://docs.celestia.org/learn/celestia-101/data-availability/).


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