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 and the EIP-20 token standard 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.

Approval transactions and bridge transactions both require gas on the network where they are submitted. Always review live wallet prompts before signing.

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?.