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

# Use Campaign Variation

> Put a variation's content in the campaign email

Copies a `ready` variation into the campaign email: its blocks, plus its subject, preview text, theme and font when it has its own. When it has its own look, the other variations that follow the email's look keep the one it had, so they don't all change with it. Draft campaigns only. Translations are re-derived from the new content.

If the email's current content is not already one of the variations, it is saved first as a new variation named "Before" plus the label you used, and returned as `savedPrevious`, so you can always go back. Using that saved variation later restores the previous content.

## Request

<ParamField path="campaignId" type="string" required>
  Campaign ID. Email campaigns only.
</ParamField>

<ParamField path="variationId" type="string" required>
  Variation ID.
</ParamField>

```bash theme={null}
curl -X POST "https://api.sequenzy.com/api/v1/campaigns/camp_abc123/variations/var_9xk2/use" \
  -H "Authorization: Bearer YOUR_API_KEY"
```

## Response

<ResponseField name="variation" type="object">
  The variation you used, now with `inUse: true`.
</ResponseField>

<ResponseField name="savedPrevious" type="object | null">
  The email's previous content, saved as a variation. `null` when it already was
  one.
</ResponseField>

<ResponseExample>
  ```json 200 theme={null}
  {
    "success": true,
    "variation": {
      "id": "var_9xk2",
      "emailId": "email_abc123",
      "parentId": null,
      "label": "V2",
      "name": "Warm and personal",
      "summary": "Rewrote the opening in a friendlier voice and shortened the body.",
      "prompt": "Three warmer, shorter versions",
      "style": "fresh",
      "status": "ready",
      "error": null,
      "subject": "A quick note about our pricing",
      "previewText": null,
      "blocks": [
        { "id": "h1", "type": "heading", "content": "A quick note about pricing", "level": 1 }
      ],
      "emailTheme": null,
      "fontFamily": null,
      "position": null,
      "inUse": true,
      "usedAt": "2026-10-14T09:20:00.000Z",
      "createdAt": "2026-10-14T09:12:00.000Z",
      "updatedAt": "2026-10-14T09:12:41.000Z"
    },
    "savedPrevious": null
  }
  ```

  ```json 400 theme={null}
  {
    "error": "Can only use a variation in a draft campaign"
  }
  ```

  ```json 401 theme={null}
  {
    "error": "Invalid API key"
  }
  ```

  ```json 404 theme={null}
  {
    "error": "Variation not found"
  }
  ```

  ```json 409 theme={null}
  {
    "error": "Only a finished variation can be used"
  }
  ```
</ResponseExample>


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