# PreviewCampaignMerge

> Preview merging two campaigns: counts of what would move. Writes nothing. Write access, campaigns toolset, MCP tool preview_campaign_merge.

**Access:** [Write](https://developer.missin.co.uk/get-started/authentication.md#access-levels)

## Variables

| Variable | Type | Required | Accepts | Description |
|---|---|---|---|---|
| `loserId` | `UUID!` | yes |  |  |
| `winnerId` | `UUID!` | yes |  |  |

## Call it

```bash curl
curl https://api.missin.co.uk/graphql/v1 \
  -H "Authorization: Bearer $MISSIN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"operationName":"PreviewCampaignMerge","variables":{"loserId":"00000000-0000-0000-0000-000000000000","winnerId":"00000000-0000-0000-0000-000000000000"},"extensions":{"persistedQuery":{"version":1,"sha256Hash":"ad40e946858e0f6e6634a51bf4278e554679d15498b098526cbc754f94259e57"}}}'
```

## Document

```graphql
mutation PreviewCampaignMerge($loserId: UUID!, $winnerId: UUID!) { __typename previewCampaignMerge(input: {winnerId: $winnerId, loserId: $loserId}) { __typename moved { __typename channels discounts incentives notes partners postRuns posts providerRecords sends signals } spendConverted userErrors { __typename code field message } } }
```

Source: https://developer.missin.co.uk/reference/campaigns/preview-campaign-merge