Invoice expired without sufficient payment.
Fired when an invoice reaches its TTL without being fully paid.
Signature: X-Halfin-Signature: t={timestamp},v1={hmac}
where hmac = HMAC-SHA256(secret, "{timestamp}.{raw_body}").
Reject if abs(now - timestamp) > 300 seconds.
Event type identifier.
"invoice.confirming" | "invoice.paid" | "invoice.overpaid" | "invoice.underpaid" | "invoice.expired" | "invoice.invalid" | "invoice.deposit_reversed"Event creation timestamp.
date-timePayload data for invoice webhook events (invoice.confirming, invoice.paid, invoice.overpaid, invoice.underpaid, invoice.expired, invoice.invalid, invoice.deposit_reversed).
Phase 4 (multi-fiat plan §D) adds amount_fiat + fiat_currency
alongside the legacy amount_usd. Dual emission lets webhook
consumers migrate on their own timeline; once the
ss_core_webhook_legacy_amount_usd_emitted_total counter drops
to zero for 7 consecutive days, Phase 5+ removes the legacy
amount_usd field.