Data Retention

How Skytells handles, retains, and purges prediction outputs and associated data.

Skytells follows an ephemeral-by-default data model. Prediction outputs — images, audio, and video files — are retained for a strictly limited window after completion, then automatically and permanently purged. This approach minimizes data exposure and ensures that your generated content does not persist on Skytells infrastructure.

Retention Timeline

Phase	Duration	Output Accessible?
Queued / Processing	Variable (depends on model and queue)	No — `output` is `null`
Succeeded	5 minutes	Yes — via CDN URLs
After retention window	Permanent	No — URLs return `404`

Once the 5-minute retention window expires, all output URLs are permanently inaccessible. There is no recovery mechanism. Download and persist your outputs immediately upon receiving the prediction.succeeded webhook or polling a succeeded status.

What Is Retained

Data type	Retained?	Duration	Purpose
Prediction metadata	Yes	Account lifetime	ID, status, timestamps, model used, billing credits. Required for usage tracking, billing, and audit.
Generated outputs (images, audio, video)	Temporarily	5 minutes after completion	Delivered via CDN for immediate download. Purged automatically.
Input prompts	No	Not stored	Prompts are processed in-memory during inference and are never written to disk or logs.
Input files (image-to-image, etc.)	Temporarily	5 minutes after completion	Purged alongside outputs.
Account data	Yes	Account lifetime	Email, billing information, API keys (hashed), usage history.
API request logs	Yes	30 days	HTTP metadata only (method, path, status code, latency). Request and response bodies are not logged.

How Purging Works

Skytells uses TTL-based (Time-To-Live) automatic purging:

Completion trigger — When a prediction reaches succeeded, failed, or canceled status, a 5-minute TTL timer starts.
CDN invalidation — After the TTL expires, the output files are deleted from the CDN origin storage.
Cache eviction — CDN edge caches are invalidated simultaneously. Cached copies at edge nodes are not served after purge.
Metadata update — The prediction's metadata.data_available field is set to false. The storage.files array is emptied.
Irreversible — Deleted files cannot be recovered by Skytells staff or any support process.

The metadata.data_available field on a prediction indicates whether outputs are still accessible. Once it becomes false, the retention window has expired.

Best Practices

Immediate Download via Webhooks

The recommended pattern is to register a webhook when creating a prediction and download outputs as soon as the prediction.succeeded event arrives:

POST /v1/predictions

{
  "model": "skytells/FLUX.2-pro",
  "input": { "prompt": "A mountain landscape at dawn" },
  "webhook": {
    "url": "https://your-server.com/webhook",
    "events": ["prediction.succeeded", "prediction.failed"]
  }
}

When your server receives the webhook:

Verify the X-Skytells-Signature header.
Extract the output array from the payload.
Download each URL to your own storage (S3, GCS, local filesystem).
Acknowledge with a 200 response.

Polling Fallback

If you cannot use webhooks, poll GET /v1/predictions/{id} until status is succeeded, then download immediately.

Do not rely on polling intervals longer than 30 seconds for time-sensitive outputs. The 5-minute retention window is strict and non-negotiable.

What Skytells Does NOT Do

Practice	Guarantee
No long-term storage	Generated outputs are never archived or backed up beyond the 5-minute retention window.
No training on your data	Your inputs and outputs are never used to train, fine-tune, or improve Skytells models.
No prompt logging	Prompts and input parameters are processed in-memory and are not written to any persistent store.
No third-party sharing	Your generated content is never shared with, sold to, or accessed by third parties.
No backup retention	Infrastructure backups explicitly exclude generated prediction content. Only account and billing metadata is backed up.

Privacy — Your Data — What personal data Skytells collects and your rights over it.
Privacy — Governance — Data residency, regional processing, and sovereignty guarantees.
Webhooks — Configure real-time notifications for prediction events.

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Data Retention

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