> ## Documentation Index
> Fetch the complete documentation index at: https://docs.datavibe.cc/llms.txt
> Use this file to discover all available pages before exploring further.

# Idempotency and retries

> Retry gate requests without creating duplicate submissions or duplicate delivery.

Set a stable `idempotency_key` for every logical send. Reusing it for a retry
returns the original action instead of creating a second billable submission.

```json theme={null}
{
  "recipient": "prospect@example.com",
  "subject": "Following up",
  "body_text": "Hi Jordan — checking in.",
  "body_html": "<p>Hi Jordan — checking in.</p>",
  "idempotency_key": "campaign-42-send-1001"
}
```

## Retry rules

* Retry transient `429` and `503` responses only after the indicated delay.
* Preserve the same idempotency key and payload.
* Do not retry authentication or validation failures unchanged.
* Do not create a new key to bypass a pending `QUEUED` action.
* Treat a conflicting payload for an existing key as an integration error.

Use exponential backoff with jitter and honor `Retry-After`, `reset_at`, and
`next_step` fields when returned.

<Danger>
  Never dispatch a second copy because a status poll timed out. Poll the existing
  `action_id` before deciding whether any retry is safe.
</Danger>