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

# approveUsdc

> Approve TradingStorage to spend trader USDC through the Ostium Builder SDK.

```ts theme={null}
await client.approveUsdc('max');
```

Or approve a fixed amount:

```ts theme={null}
await client.approveUsdc('1000');
```

## Important behavior

* available in self modes
* unavailable in delegated modes
* required before `openTrade()` and some `updateCollateral()` top-ups

## Response schema

```ts theme={null}
interface Response {
  txHash: `0x${string}`;
  smartAccountAddress?: `0x${string}`;
}
```