> ## 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.

# Estimate In-App Campaign Recipients

> Count the contacts who match an audience now

Counts the contacts who match an audience now. Email status doesn't matter. The count is a snapshot: contacts who join the audience while the campaign is live get it too, and contacts who leave it before their app next opens don't. Requires the `campaigns:read` scope.

## Request

**targetLists** `object` *required*

Audience, the same shape as campaign `targetLists`.

```bash theme={null}
curl -X POST "https://api.sequenzy.com/api/v1/in-app/campaigns/estimate" \
  --header "Authorization: Bearer $SEQUENZY_API_KEY" \
  --header "Content-Type: application/json" \
  --data '{"targetLists": {"type": "segment", "segmentId": "seg_123"}}'
```

## Responses

```json 200 theme={null}
{
  "success": true,
  "audienceCount": 1200
}
```

```json 400 theme={null}
{
  "error": "Invalid audience."
}
```

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

```json 403 theme={null}
{
  "error": "API key is missing required scope: campaigns:read"
}
```


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