## Enroll and cancel contacts

**post** `/v1/sequences/{id}/enrollments`

Enrolls the contacts in `add` and cancels the open enrollments of the contacts in `remove`, in one request: if any addition is invalid, nothing changes. Send add, remove or both, with at most 25 contact IDs in total; duplicate IDs are ignored, and an ID cannot be in both lists. The response has one result per contact: `enrolled`, `already_enrolled`, `unenrolled`, or `no_active_enrollment` for a removal with nothing open.

A contact already enrolled, paused included, is left as is; one whose earlier enrollment ended is enrolled again. Cancelling stops the contact’s remaining steps and leaves the enrollment readable with status `CANCELLED`. A paused sequence accepts enrollments and sends to them once it is activated; sending starts asynchronously.

Returns 400 `sequence_not_published` for a sequence that has never been published, and 400 `invalid_configuration` with `invalidContacts` naming each contact that cannot be enrolled and why. See <u>[Sequence errors](/using-the-api/errors/#sequence-errors)</u>.

**[Required scope](/using-the-api/scopes/):** `sequences:update`

**[Rate limit category](/using-the-api/rate-limits/):** Write

### Path Parameters

- `id: string`

  Unique identifier of the sequence.

### Body Parameters

- `add: optional array of string`

  Contact IDs to enroll. Open enrollments are unchanged; contacts whose prior enrollment ended are enrolled again.

- `remove: optional array of string`

  Contact IDs to unenroll. Cancels open enrollments and preserves their history.

### Returns

- `SequenceUpdateEnrollmentsResponse object { results }`

  - `results: array of object { contactId, enrollmentId, outcome }  or object { contactId, enrollmentId, outcome }`

    One result per distinct contact, additions first, then removals.

    - `EnrollmentChanged object { contactId, enrollmentId, outcome }`

      - `contactId: string`

        ID of the contact.

      - `enrollmentId: string`

        ID of the enrollment the outcome applies to.

      - `outcome: "enrolled" or "already_enrolled" or "unenrolled"`

        `enrolled` created the enrollment, `already_enrolled` left an open one as is, `unenrolled` cancelled it.

        - `"enrolled"`

        - `"already_enrolled"`

        - `"unenrolled"`

    - `NothingToCancel object { contactId, enrollmentId, outcome }`

      - `contactId: string`

        ID of the contact.

      - `enrollmentId: unknown`

        Always null.

      - `outcome: "no_active_enrollment"`

        The contact had no open enrollment to cancel.

        - `"no_active_enrollment"`

### Example

```http
curl https://api.lightfield.app/v1/sequences/$ID/enrollments \
    -H 'Content-Type: application/json' \
    -H 'Lightfield-Version: 2026-03-01' \
    -H "Authorization: Bearer $API_KEY" \
    -d '{}'
```

#### Response

```json
{
  "results": [
    {
      "contactId": "contactId",
      "enrollmentId": "enrollmentId",
      "outcome": "enrolled"
    }
  ]
}
```