---
title: "Preview a sequence timing operation"
method: POST
path: "/projects/{projectId}/timeline/operations/preview"
tags: ["Timeline Editing"]
---

# Preview a sequence timing operation

`POST /projects/{projectId}/timeline/operations/preview`

## Request

- Base URL: `https://blitzreels.com/api/v1`
- URL: `https://blitzreels.com/api/v1/projects/{projectId}/timeline/operations/preview`
- Auth: API key in header `Authorization`

Preview a sequence timing operation.

## Path parameters

- `projectId` string, required

## Request body

- object
  - `operation` union, required
    - object
      - `operation_id` 'timeline.item.trim', required
      - `timeline_item_id` string, required
      - `trim_start_delta_seconds` number, required
      - `trim_end_delta_seconds` number, required
      - `snap_to_frame` boolean, required
    - object
      - `operation_id` 'timeline.item.split', required
      - `timeline_item_id` string, required
      - `split_at_seconds` number, required
      - `snap_to_frame` boolean, required
  - `expected_revision` integer, nullable, required

## Response `200`

Successful response

- object
  - `operation_id` 'timeline.item.trim' | 'timeline.item.split', required
  - `project_id` string, required
  - `current_revision` integer, required
  - `expected_revision` integer, nullable, required
  - `destructive` boolean, required
  - `affected_timeline_item_ids` string[], required
  - `would_create_timeline_item_ids` string[], required
  - `would_delete_timeline_item_ids` string[], required
  - `change_count` integer, required
  - `warnings` string[], required

## Other responses

- `400`: Invalid input data
- `401`: Authorization not provided
- `403`: Insufficient access
- `500`: Internal server error

---

[API](https://skmtc.dev/blitzreels/apis/blitzreels-api.md) · [All operations](https://skmtc.dev/blitzreels/apis/blitzreels-api/llms.txt) · [OpenAPI document](https://skmtc.dev/blitzreels/apis/blitzreels-api/revisions/35608b12471d?raw)