> For the complete documentation index, see [llms.txt](https://docs.yo.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.yo.xyz/integrations/integration-guides/sdk/react/hooks/use-approve.md).

# use approve

Mutation hook for ERC-20 token approvals. Supports both exact amounts and unlimited (`maxUint256`) approval.

```tsx
const { approve, approveMax, isPending, isSuccess } = useApprove({ token })
```

## Usage

```tsx
import { useApprove } from '@yo-protocol/react'
import { parseEther } from 'viem'

function ApproveButton({ token }: { token: `0x${string}` }) {
  const {
    approve,
    approveMax,
    isPending,
    isSuccess,
    hash,
    error,
    reset,
  } = useApprove({
    token,
    onSubmitted: (hash) => console.log('Approved:', hash),
  })

  return (
    <div>
      <button onClick={() => approve(parseEther('10'))} disabled={isPending}>
        {isPending ? 'Approving...' : 'Approve 10 tokens'}
      </button>
      <button onClick={approveMax} disabled={isPending}>
        Approve unlimited
      </button>

      {isSuccess && <p>Approved! Tx: {hash}</p>}
      {error && (
        <p>
          Error: {error.message}
          <button onClick={reset}>Dismiss</button>
        </p>
      )}
    </div>
  )
}
```

{% hint style="info" %}
**When to approve**

Call `approve` or `approveMax` before the first deposit. The gateway checks allowance on-chain and will revert if it's insufficient. You can check the current allowance via `YoClient.hasEnoughAllowance()`.
{% endhint %}

## Options

| Option        | Type                     | Default              | Description                                        |
| ------------- | ------------------------ | -------------------- | -------------------------------------------------- |
| `token`       | `Address`                | —                    | **Required.** ERC-20 token address to approve      |
| `spender`     | `Address`                | `YO_GATEWAY_ADDRESS` | Contract that receives the allowance               |
| `onSubmitted` | `(hash: Hash) => void`   | —                    | Called after the transaction is sent               |
| `onConfirmed` | `(hash: Hash) => void`   | —                    | Called after the transaction is confirmed on-chain |
| `onError`     | `(error: Error) => void` | —                    | Called on error                                    |

## Return Value

| Field        | Type                                | Description                                             |
| ------------ | ----------------------------------- | ------------------------------------------------------- |
| `approve`    | `(amount: bigint) => Promise<Hash>` | Approve a specific token amount                         |
| `approveMax` | `() => Promise<Hash>`               | Approve `maxUint256` (unlimited)                        |
| `isPending`  | `boolean`                           | `true` while the transaction is being sent or confirmed |
| `isError`    | `boolean`                           | `true` if the transaction failed                        |
| `error`      | `Error \| null`                     | Error object                                            |
| `isSuccess`  | `boolean`                           | `true` after the transaction is confirmed on-chain      |
| `hash`       | `Hash \| undefined`                 | Transaction hash once submitted                         |
| `reset`      | `() => void`                        | Reset all state back to idle                            |

## Behavior

| Behavior                  | Detail                                                                                 |
| ------------------------- | -------------------------------------------------------------------------------------- |
| **Default spender**       | Defaults to `YO_GATEWAY_ADDRESS` — the standard deposit entry point                    |
| **Confirmation tracking** | Uses `useWaitForTransactionReceipt` internally                                         |
| **Error propagation**     | Fires both the local `onError` callback and the global `YieldProvider.onError` handler |


---

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