> ## 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.

# Errors

> Reference for Ostium SDK error classes and error codes.

The SDK exposes two error classes:

* `OstiumError` for client creation, transaction building, signing, submission, and contract interaction
* `OstiumSubgraphError` for subgraph reads, builder API reads, parsing, and stream-related data lookups

## OstiumError

`OstiumError` is thrown by the main `OstiumClient` surface.

```ts theme={null}
import { OstiumError, OstiumErrorCode } from '@ostium/builder-sdk';

try {
  await client.openTrade(params);
} catch (error) {
  if (error instanceof OstiumError) {
    console.error(error.code, error.message);
  }
}
```

### Error codes

| Code                     | Meaning                                                                                           |
| ------------------------ | ------------------------------------------------------------------------------------------------- |
| `INVALID_CONFIG`         | The client was created with incompatible or missing configuration for the selected mode.          |
| `VALIDATION_FAILED`      | Input parameters failed SDK validation before submission.                                         |
| `ALLOWANCE_INSUFFICIENT` | The trader does not have enough USDC allowance for the requested action.                          |
| `SUBMISSION_FAILED`      | Transaction or user operation submission failed.                                                  |
| `DELEGATION_FAILED`      | Delegation setup is missing or the requested delegated action is not allowed in the current mode. |
| `CONTRACT_ERROR`         | A contract read or write failed.                                                                  |
| `NETWORK_ERROR`          | An RPC or network request failed.                                                                 |

## OstiumSubgraphError

`OstiumSubgraphError` is thrown by read methods backed by the subgraph or builder API.

```ts theme={null}
import { OstiumSubgraphError, OstiumSubgraphErrorCode } from '@ostium/builder-sdk';

try {
  const positions = await client.getOpenPositions({ user: '0xTraderAddress' });
} catch (error) {
  if (error instanceof OstiumSubgraphError) {
    console.error(error.code, error.message);
  }
}
```

### Error codes

| Code             | Meaning                                                                  |
| ---------------- | ------------------------------------------------------------------------ |
| `INVALID_CONFIG` | The read client was created with invalid endpoint or mode configuration. |
| `INVALID_PARAMS` | The read method was called with invalid arguments.                       |
| `FETCH_FAILED`   | The subgraph or builder API request failed.                              |
| `NOT_FOUND`      | A requested entity or pair could not be found.                           |
| `PARSE_ERROR`    | The SDK received data but could not parse it into the expected shape.    |

## Recommended handling

* Catch `OstiumError` around trade setup and write methods.
* Catch `OstiumSubgraphError` around read methods and streams.
* Log both `error.code` and `error.message`.
* If present, inspect `error.cause` for the underlying RPC, contract, or fetch error.