> 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/guides/token-approvals.md).

# token approvals

Token approvals let an ERC-20 contract give another contract permission to move a limited amount of your tokens. When you bridge tokens such as USDC to Manta Pacific, an approval is usually required before the bridge can transfer the token from your wallet.

## What Is a Token Approval?

ETH can be sent directly with a transaction. ERC-20 tokens work differently: the token contract tracks balances, and a separate contract cannot move your tokens unless you approve it first.

An approval sets an **allowance**:

| Term    | Meaning                                                                |
| ------- | ---------------------------------------------------------------------- |
| Owner   | Your wallet address.                                                   |
| Token   | The ERC-20 asset you are approving, such as USDC.                      |
| Spender | The contract allowed to move tokens from your wallet.                  |
| Amount  | The maximum token amount the spender can transfer under that approval. |

The ERC-20 standard defines `approve`, `allowance`, and `transferFrom` as part of this model. See the [ethereum.org ERC-20 overview](https://ethereum.org/developers/docs/standards/tokens/erc-20/) and the [EIP-20 token standard](https://eips.ethereum.org/EIPS/eip-20) for the underlying interface.

## Why Bridging Tokens Needs Approval

When depositing an ERC-20 token from Ethereum L1 to Manta Pacific, the bridge contract needs permission to pull the token from your wallet and lock or process it as part of the deposit flow. This is separate from the bridge transaction itself.

For a typical ERC-20 deposit:

1. Select the token and amount in the bridge flow.
2. Approve the token spend if your current allowance is too low.
3. Submit the bridge deposit transaction.
4. Wait for the deposit to be processed on Manta Pacific.

If you are following the USDC flow, see [Bridge USDC to Manta Pacific](file:///2078213/guides/bridge-usdc-to-manta-pacific.md).

{% hint style="info" %}
Approval transactions and bridge transactions both require gas on the network where they are submitted. Always review live wallet prompts before signing.
{% endhint %}

## Limited vs Unlimited Approvals

Some wallets and apps may offer different approval amounts.

| Approval type      | How it works                                                     | Tradeoff                                                                                      |
| ------------------ | ---------------------------------------------------------------- | --------------------------------------------------------------------------------------------- |
| Exact approval     | Approves only the amount needed for the current bridge transfer. | More restrictive, but you may need to approve again next time.                                |
| Custom approval    | Approves an amount you choose.                                   | Useful if you want a specific limit above the current transfer amount.                        |
| Unlimited approval | Approves a very large allowance.                                 | Convenient for repeated use, but leaves more permission outstanding until revoked or changed. |

For most users, an exact or custom approval is easier to reason about. Use unlimited approvals only when you understand the contract and the ongoing permission you are granting.

## How to Review an Approval

Before signing, check the wallet prompt carefully:

1. Confirm the **token** is the asset you intend to bridge.
2. Confirm the **spender** is the expected bridge contract or app interaction.
3. Confirm the **amount** matches your intended allowance.
4. Check that the transaction is on the expected source network.
5. Reject the request if the token, spender, or amount looks unfamiliar.

Approvals do not move tokens by themselves. They create permission. A later contract call can use that permission up to the approved amount.

## How to Reduce or Revoke Approvals

You can usually reduce approval exposure by:

* choosing exact or custom approvals when your wallet supports them;
* lowering an existing allowance to a smaller amount;
* revoking an allowance you no longer need through a reputable token approval management tool or block explorer;
* periodically reviewing active allowances for wallets used with bridges and DeFi apps.

Revoking or changing an approval is an on-chain transaction and requires gas. Verify contract addresses and network selection before making changes.

## Security Checklist

Use approvals as part of your normal bridge safety review:

* Use official links and avoid signing from unknown sites.
* Treat approvals as permissions, not just confirmations.
* Prefer smaller allowances for one-time transfers.
* Revoke old allowances when they are no longer needed.
* Review the broader bridge risk model in [Is Manta Bridge Safe?](file:///2078213/security/is-manta-bridge-safe.md).


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://mantabridge.gitbook.io/manta-bridge-docs/guides/token-approvals.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.