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

# List measurement sources

> List the measurement data sources registered for an advertiser

`GET /api/v2/buyer/advertisers/{advertiserId}/measurement-sources`

Lists measurement sources for an advertiser — the MMM feeds, brand-lift studies, and partner data sources that supply outcome records. Filter by outcome type and status.

## Request

<CodeGroup>
  ```bash curl theme={null}
  curl "https://api.apostra.com/api/v2/buyer/advertisers/12345/measurement-sources?status=active&take=50&skip=0" \
    -H "Authorization: Bearer $SCOPE3_API_KEY"
  ```
</CodeGroup>

## Parameters

| Field | Type | Required | Notes |
| - | - | - | - |
| `advertiserId` | string | Yes | Path parameter — the owning advertiser |
| `outcomeType` | string | No | Filter by outcome type |
| `status` | enum | No | `pending`, `active`, or `paused` |
| `take` | integer | No | Page size, max 250 (default 50) |
| `skip` | integer | No | Offset for pagination (default 0) |

## Response

```json theme={null}
[
  {
    "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "advertiserId": "12345",
    "sourceKey": "acme_incr_rev",
    "name": "Acme Incrementality",
    "outcomeType": "incremental_revenue",
    "outcomeTypes": [],
    "granularity": "geo_week",
    "lagWeeks": 1,
    "cadence": "weekly",
    "provider": "acme-mmm",
    "signalWeight": 1,
    "status": "active",
    "vendor": null,
    "vendorMetrics": [],
    "createdAt": "2026-01-15T10:30:00Z",
    "updatedAt": "2026-01-15T10:30:00Z"
  }
]
```

The `data` payload is the array of matching sources. The total count and paging state are returned in the `meta.pagination` block — this endpoint uses offset pagination (`take` / `skip`); see [Pagination](/v2/reference/pagination). Use [Get measurement source](/v2/buyer/measurement/tasks/get-measurement-source) for the full resource.

## Errors

* `404 NOT_FOUND` — `advertiserId` does not exist or is not visible to the authenticated account.

See [Errors](/v2/reference/errors) for the full error contract.

## Related

<CardGroup cols={2}>
  <Card title="Measurement tasks" href="/v2/buyer/measurement/tasks" icon="list-check">
    All measurement operations
  </Card>

  <Card title="Measurement overview" href="/v2/guides/measurement-incrementality" icon="chart-line">
    Pipeline, belief state, and concepts
  </Card>

  <Card title="Create measurement source" href="/v2/buyer/measurement/tasks/create-measurement-source" icon="plus">
    Register a new source
  </Card>
</CardGroup>


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