> For the complete documentation index, see [llms.txt](https://docs.millimetric.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.millimetric.ai/api-reference/sources.md).

# GET /v1/sources

GET /v1/sources — top sources/mediums with the FB social-vs-paid split.

Top sources (and optionally source × medium) for the project. **This is the endpoint that surfaces the Facebook social-vs-paid split.**

## Auth

|                |        |
| -------------- | ------ |
| Required scope | `read` |
| Key kinds      | `rk_*` |

## Request

```http
GET /v1/sources?from=…&to=…&breakdown=source_medium
Authorization: Bearer rk_live_…
```

### Query parameters

| Name        | Required | Notes                                  |
| ----------- | -------- | -------------------------------------- |
| `from`      | **yes**  | ISO 8601 timestamp (inclusive).        |
| `to`        | **yes**  | ISO 8601 timestamp (exclusive).        |
| `breakdown` | no       | `source_medium` (default) or `source`. |
| `limit`     | no       | 1–200, default 50.                     |

## Response

```json
{
  "breakdown": "source_medium",
  "rows": [
    { "source": "facebook", "medium": "paid",   "events": 6, "uniques": 6, "paid_share": 1.0 },
    { "source": "facebook", "medium": "social", "events": 3, "uniques": 3, "paid_share": 0.0 },
    { "source": "google",   "medium": "paid",   "events": 3, "uniques": 3, "paid_share": 1.0 },
    { "source": "direct",   "medium": "direct", "events": 7, "uniques": 7, "paid_share": 0.0 }
  ]
}
```

Each row:

* `events` — total events matching the breakdown.
* `uniques` — distinct `anonymous_id`s (HyperLogLog estimate).
* `paid_share` — `count(medium='paid') / count(*)` for the row. For `breakdown=source_medium` it's trivially 0 or 1; for `breakdown=source` it reveals what fraction of a source's traffic is paid (useful for "X% of our Facebook is paid").

## Examples

### "What's our Facebook social vs paid split this month?"

```bash
curl -G "https://api.millimetric.ai/v1/sources" \
  -H "Authorization: Bearer $RK_KEY" \
  --data-urlencode "from=2026-05-01T00:00:00Z" \
  --data-urlencode "to=2026-06-01T00:00:00Z"
# rows include separate facebook/paid and facebook/social entries
```

### "Where does our traffic come from, ignoring paid/organic?"

```bash
curl -G "https://api.millimetric.ai/v1/sources" \
  -H "Authorization: Bearer $RK_KEY" \
  --data-urlencode "from=2026-05-01T00:00:00Z" \
  --data-urlencode "to=2026-06-01T00:00:00Z" \
  --data-urlencode "breakdown=source"
# rows include a paid_share column for each source
```

## Related

* For more flexible aggregations, use [`/v1/stats`](/api-reference/stats.md) with `group_by=source,medium`.
* For session-level entry source (better for revenue attribution), query `sessions_v` directly.


---

# Agent Instructions
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## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.millimetric.ai/api-reference/sources.md?ask=<question>&goal=<user_goal>
```

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Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.