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

# Error Handling

> Learn how to implement proper error handling in Blinks to provide users with clear feedback and prevent failed transactions.

<img src="https://res.cloudinary.com/dnxjhra4h/image/upload/f_auto,q_auto/v1751209550/dialect-docs/error-msg-example.png" alt="Example of error message displayed in Blink UI" />

Proper error handling is crucial for Blinks as it provides users with clear feedback when something goes wrong. When an error occurs, the `ActionError` object displays the error message directly in the Blink UI, preventing failed transactions and improving user experience.

## Key Concepts

* **ActionError Object**: Wrap error messages in `ActionError` to display them in the Blink UI
* **Input Validation**: Always validate user inputs before processing transactions
* **User-Friendly Messages**: Provide clear, actionable error messages that help users understand what went wrong
* **HTTP Status Codes**: Use appropriate status codes (400 for validation errors, 500 for server errors)

## Best Practices

<CardGroup cols={2}>
  <Card title="Input Validation" icon="shield-check">
    Validate all inputs before expensive operations
  </Card>

  <Card title="User-Friendly Messages" icon="message">
    Use specific error messages that guide users to the solution
  </Card>

  <Card title="Graceful Error Handling" icon="handshake">
    Always catch and handle errors gracefully
  </Card>

  <Card title="Server-Side Logging" icon="terminal">
    Log errors server-side for debugging while showing user-friendly messages in the UI
  </Card>
</CardGroup>

## Error Handling Example

Here's how to implement input validation and error handling in our [donation Blink](/blinks/blinks-provider/build-your-first-blink) example:

```typescript theme={null}
import {
  ActionPostRequest,
  ActionPostResponse,
  ActionError,
  ACTIONS_CORS_HEADERS,
} from "@solana/actions";
import { PublicKey } from "@solana/web3.js";

// Other code, such as headers, GET and OPTIONS request, etc. 

export const POST = async (req: Request) => {
  try {
    const url = new URL(req.url);
    const amount = Number(url.searchParams.get("amount"));
    
    // Validate donation amount
    if (!amount || isNaN(amount)) {
      throw new Error("Please enter a valid donation amount");
    }
    
    if (amount < 0.05) {
      throw new Error("Minimum donation is 0.05 SOL");
    }
    
    if (amount > 10) {
      throw new Error("Maximum donation is 10 SOL per transaction");
    }
    
    const request: ActionPostRequest = await req.json();
    
    // Nested validation example: Validate wallet address
    let payer: PublicKey;
    try {
      payer = new PublicKey(request.account);
    } catch {
      throw new Error("Invalid wallet address format");
    }
    
    // Process transaction (simplified for example)
    const transaction = await prepareTransaction(
      connection,
      payer,
      receiver,
      amount
    );
    
    const response: ActionPostResponse = {
      type: "transaction",
      transaction: Buffer.from(transaction.serialize()).toString("base64"),
    };
    
    return Response.json(response, {
      status: 200,
      headers
    });
    
  } catch (error) {
    console.error("Donation error:", error);
    
    // Return ActionError for Blink UI display
    const errorResponse: ActionError = {
      message: error instanceof Error ? error.message : "Internal server error"
    };
    
    return new Response(JSON.stringify(errorResponse), {
      status: 500,
      headers
    });
  }
};

// prepareTransaction function ... 

```