Credits for the whole batch are reserved together: if the balance, spend cap, key limit or free daily cap can't cover every valid request, none is queued and each gets the error (invalid requests get their own 400 entry either way). Each job is settled and refunded on its own once it runs.

Retries. Send an Idempotency-Key to make the call safe to retry: for 24 hours a repeat with the same key and the same body returns the first response (with Idempotent-Replayed: true) without queueing or billing again. The same key with a different body is rejected with 422 idempotency_key_reused; a repeat while the first call is still running gets 409.

Webhooks. Every delivery is a POST with X-SerpKite-Event: batch.completed, X-SerpKite-Delivery (the job id), X-SerpKite-Timestamp (Unix seconds) and X-SerpKite-Signature: v1=<hex HMAC-SHA256(secret, "<timestamp>.<raw body>")>. Deliveries are always signed; the account's secret is created with its first webhook and revealed by rotating it (dashboard Settings → Webhooks). Verify by recomputing the HMAC over the raw body, comparing in constant time, and rejecting timestamps older than 5 minutes. The SDKs ship verifyWebhook / verify_webhook / VerifyWebhook.

{
  "batches": [
    {
      "endpoint": "/v1/search"
    }
  ]
}