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

# Resend Passwordless Code

> Generate a new code for an existing authentication attempt

## Overview

To resend a passwordless code, use the [Create Code endpoint](/api/passwordless/create-code) with the `deviceId` parameter.

## How It Works

When you call the Create Code endpoint with an existing `deviceId`, it generates a new code for that device while maintaining the same authentication session. This is the recommended way to implement code resend functionality.

## Request

```bash theme={null}
POST /recipe/signinup/code
```

**Request Body:**

```json theme={null}
{
  "deviceId": "existing-device-id"
}
```

## Response

Same as [Create Code](/api/passwordless/create-code#response):

```json theme={null}
{
  "status": "OK",
  "preAuthSessionId": "string",
  "codeId": "string",
  "deviceId": "string",
  "userInputCode": "string",
  "linkCode": "string",
  "timeCreated": 1234567890,
  "codeLifetime": 900000
}
```

## Example

```bash theme={null}
curl -X POST https://your-api.com/recipe/signinup/code \
  -H "Content-Type: application/json" \
  -d '{
    "deviceId": "abc123-device-id"
  }'
```

## Implementation Example

```javascript theme={null}
// Initial code creation
const { deviceId, userInputCode } = await createCode({
  email: "user@example.com"
});

// Send code to user...

// User requests resend
const { userInputCode: newCode } = await createCode({
  deviceId: deviceId  // Use the same deviceId
});

// Send new code to user...
```

## Notes

* The `deviceId` must be from a valid, active authentication session
* The `preAuthSessionId` remains the same across resends
* Failed verification attempts are tracked across all codes for the device
* If the device is invalid or expired, you'll receive a `RESTART_FLOW_ERROR`
* Each resend generates a new `userInputCode` and `linkCode`
* The previous code is invalidated when a new one is created

## Error Handling

If the device ID is invalid or the session has expired:

```json theme={null}
{
  "status": "RESTART_FLOW_ERROR"
}
```

In this case, you should restart the authentication flow by creating a new code with the user's email or phone number.