Kaps + n8n

Use n8n to automate captioned renders with the Kaps Render API. There is no dedicated Kaps node — the built-in HTTP Request node (and optional Webhook trigger) is enough.

Prerequisites

  1. A Kaps account (kaps.ai) with credits.
  2. An API key from Settings → API keys (ksk_live_…, shown once).
  3. n8n (cloud or self-hosted).

API base URL: https://api.kaps.ai/functions/v1

Store your API key

In n8n, create a credential:

  1. Credentials → Add credential → Header Auth
  2. Name: Authorization
  3. Value: Bearer ksk_live_... (include the Bearer prefix)

Use this credential on every HTTP Request node below.

Starter workflow (import)

A minimal “caption video from URL” workflow is in the repo:

docs/workflows/kaps-caption-from-url.json

In n8n: Workflows → Import from file (or paste JSON). Then:

  1. Open the Configure node and set preset_id and video_url.
  2. Attach your Header Auth credential to the HTTP Request nodes.
  3. Run manually to test.

The template uses wait: true so short clips finish in one execution (blocks up to ~4 minutes). For longer videos, use the async + webhook pattern below.

Build it yourself

Recommended flow: credits → estimate → create → status (or webhook). See Render API for field details.

1. Check credits (optional)

Setting Value
Method GET
URL https://api.kaps.ai/functions/v1/api-credits
Auth Header Auth (see above)

2. Estimate cost (optional)

Setting Value
Method POST
URL https://api.kaps.ai/functions/v1/api-render-estimate
Auth Header Auth
Body content type JSON

Example body:

{
  "duration_seconds": 185,
  "resolution": "1080p",
  "fps": 30
}

Check can_proceed before creating a render. Still returns HTTP 200 when balance or upload limits would block a real job.

3. List presets (optional)

Setting Value
Method GET
URL https://api.kaps.ai/functions/v1/api-presets-list
Auth Header Auth (see above)

Pick a preset_id from the response.

4. Start a render

Setting Value
Method POST
URL https://api.kaps.ai/functions/v1/api-render-create
Auth Header Auth
Body content type JSON

Example body (sync — good for short clips):

{
  "preset_id": "",
  "video_url": "",
  "resolution": "1080p",
  "fps": 30,
  "wait": true
}

Example body (async — recommended for longer videos):

{
  "preset_id": "",
  "video_url": "",
  "resolution": "1080p",
  "webhook_url": "https://your-n8n.example.com/webhook/kaps-render-complete"
}

When wait is omitted or false, the response includes request_id and status_url. Poll with GET https://api.kaps.ai/functions/v1/api-render-status?id=.

  1. Add a Webhook trigger node (POST, path e.g. kaps-render-complete).
  2. Copy the production webhook URL into webhook_url on the create request.
  3. When the render finishes, Kaps POSTs JSON including output_url, status, and credits_used.

See Render API → Webhooks for payload shape and HMAC verification (X-Kaps-Signature). For internal workflows you can skip verification; for production endpoints use a Code node to verify the signature with your key’s webhook signing secret.

6. Poll loop (alternative to webhooks)

If you cannot expose a webhook:

HTTP Request (create, wait: false)
  → Wait (5s)
  → HTTP Request (GET status)
  → IF status not in complete/failed → loop back to Wait

Example: Google Drive → Kaps

n8n has native nodes for the full pipeline when your source file lives on Drive:

Google Drive Trigger
  → Google Drive (Download)
  → S3 / R2 / B2 (Upload)
  → Set (public file URL)
  → HTTP Request (Kaps create render)

Use the file ID from the share link (drive.google.com/file/d/FILE_ID/view) in the Download node.

Side note — Google Drive links: A Drive share URL is not a direct video URL. Kaps fetches video_url server-side and needs raw file bytes (S3, R2, CDN, etc.). Pasting a Drive link into video_url returns HTML and ingest fails. Download with n8n’s Google Drive node, upload to a bucket with a public (or signed) object URL, then pass that URL to Kaps — or upload the asset in the Kaps app and use asset_id instead.

For large files, enable n8n filesystem binary mode on self-hosted instances.

Operations quick reference

Action Method Path
Credit balance GET /api-credits
Estimate cost POST /api-render-estimate
List presets GET /api-presets-list
Create render POST /api-render-create
Poll status GET /api-render-status?id={request_id}

Full field lists, errors, and pricing: Render API.

Further reading