# Compare A/B cohorts

`GET https://api.versionseven.ai/v1/campaigns/{campaign_id}/ab-cohorts`

Per-arm counts for leads first contacted at or after `since`. Each lead counts once, in the arm it was assigned, with its first reply, first positive reply and first negative reply: `arms.a` and `arms.b` each carry `contacted`, `replied`, `positive` and `negative`.

Unlike [Get campaign analytics](https://docs.versionseven.ai/api-reference/campaigns/get-campaign-analysis), every number is over the same set of leads, those who could have seen either arm, so the arms can be compared directly. Pass the time the test was turned on as `since`.

- Required scope: `campaigns:read`

## Request

**cURL**

```bash
curl "https://api.versionseven.ai/v1/campaigns/550e8400-e29b-41d4-a716-446655440000/ab-cohorts?since=string" \
  -H "Authorization: Bearer $VICTORIA_API_KEY"
```

**Node.js**

```javascript
const response = await fetch("https://api.versionseven.ai/v1/campaigns/550e8400-e29b-41d4-a716-446655440000/ab-cohorts?since=string", {
  headers: {
    Authorization: `Bearer ${process.env.VICTORIA_API_KEY}`,
  },
});

const data = await response.json();
```

**Python**

```python
import os

import requests

response = requests.get(
    "https://api.versionseven.ai/v1/campaigns/550e8400-e29b-41d4-a716-446655440000/ab-cohorts",
    headers={
        "Authorization": f"Bearer {os.environ['VICTORIA_API_KEY']}",
    },
    params={
        "since": "string",
    },
)
data = response.json()
```

## Headers

- `Authorization` (string, required): `Bearer` followed by a space and your API key, for example `Bearer vk_…`.

## Path parameters

- `campaign_id` (string · uuid, required): ID of the campaign.

## Query parameters

- `since` (string, required): ISO 8601 timestamp the test started. Only leads first contacted at or after it count. Answers `400 INVALID_DATE_FILTER` if it can't be parsed.

## Response

### `200`

```json
{
  "campaign_id": "550e8400-e29b-41d4-a716-446655440000",
  "since": "string",
  "arms": {},
  "success": true
}
```

- `campaign_id` (string, required)
- `since` (string, required)
- `arms` (object, optional): a / b -> {contacted, replied, positive, negative}
- `success` (boolean, optional, default `true`)

## Errors

Errors share one JSON body: `success`, `error`, `message`, optional `details`, and `request_id`. For example:

```json
{
  "success": false,
  "error": "UNAUTHORIZED",
  "message": "Invalid or inactive API key",
  "request_id": "734d11a1-54d4-414c-9e8d-4e1ada977db4"
}
```

| Status | Code | Meaning |
| --- | --- | --- |
| 400 | `VALIDATION_ERROR` | The request didn't match the endpoint's schema: a missing or malformed field, a bad query parameter, or a value out of range. `details.errors` lists each failing field with its `field`, `message` and `type`. |
| 400 | `INVALID_DATE_FILTER` | `date_filter` must be a number of days such as `30d`, or an ISO 8601 timestamp. |
| 401 | `UNAUTHORIZED` | The `Authorization` header is missing or malformed, or the API key is unknown or has been deactivated. |
| 401 | `API_KEY_EXPIRED` | The API key is past its expiry date. Create a new key in the Victoria AI app. |
| 403 | `INSUFFICIENT_SCOPE` | The API key doesn't have the scope this endpoint requires, such as `leads:write`. |
| 403 | `ORGANIZATION_DEACTIVATED` | The organization that owns this API key has been deactivated. |
| 404 | `CAMPAIGN_NOT_FOUND` | No campaign with this ID exists in your organization. |
| 404 | `NOT_FOUND` | No endpoint matches the path. A resource ID in the path that isn't a valid UUID also answers `NOT_FOUND`. |
| 429 | `RATE_LIMITED` | Too many requests for this API key: more than 100 a minute to one endpoint, or 600 a minute in total. Retry after the number of seconds in the `Retry-After` header. See [Rate limits](https://docs.versionseven.ai/guides/rate-limits). |
| 500 | `INTERNAL_ERROR` | Something failed on our side. The response never includes internal details; quote its `request_id` when you contact support. |
| 503 | `UPSTREAM_TIMEOUT` | A service the API depends on timed out. The request is safe to retry. |
| 503 | `AUTH_UNAVAILABLE` | The API key couldn't be checked because the authentication service was unavailable. The request is safe to retry. |

## Response headers

| Header | Description |
| --- | --- |
| `X-Request-ID` | Correlation ID for the request, also returned as `request_id` in error bodies. Send your own `X-Request-ID`, up to 128 letters, digits, `.`, `_`, `:` or `-`, and it's used instead. |
| `RateLimit-Limit` | Requests allowed to this endpoint per minute. |
| `RateLimit-Remaining` | Requests you can still send to this endpoint right now. |
| `RateLimit-Reset` | Seconds until the endpoint's full limit is available again. |
| `Retry-After` | On a `429`: seconds to wait before retrying. |