subscription.* events

Billing fails but grace period is active.

When this fires

A scheduled charge fails but the subscription remains within its grace window. The platform will continue to attempt collection.

Coverage is partial: only Stripe and Razorpay report the past-due transition back to Subscriby. Failed renewals on PayPal, Paystack, Skrill, CeyPay, and CoinPayments emit payment.failed without a matching subscription.past_due, so treat payment.failed as the reliable cross-provider signal.

Caveats

  • Pairs with a payment.failed event for the underlying charge.
  • If retries succeed, subscription.renewed follows. If grace expires, subscription.unpaid fires instead.

Related events

  • payment.failed: paired payment event.
  • subscription.unpaid: grace-window terminal state.
postWebhooksubscription.past_due

Headers

SB-Signaturestring required

t=<unix seconds>,v1=<hex>: the HMAC-SHA256 of "<t>.<raw body>" under the endpoint's secret. Verify it before acting, and refuse a t more than 300 seconds from now. During a secret rotation a v0= signature under the previous secret may precede v1=.

SB-Event-Idstring required

The event's ULID, bare. The envelope's id is the same ULID prefixed evt_, so strip the prefix before comparing. Deduplicate on it: a retry carries the same id.

SB-Event-Namestring required

The event name, the same as the envelope's type.

Content-Typestring required

Always application/json.

User-Agentstring required

Always Subscriby-Webhooks/1.0.

Payload

idstring required

A ULID unique to the event, prefixed evt_. Every retry carries the same id, so it is the key to deduplicate on.

type'subscription.past_due' required

The event name, always subscription.past_due here.

created_atstring date-time required

When the event was emitted, server time, ISO 8601.

api_versionstring required

The contract version of the payload shape, 2026-05-01 today. A breaking change to a shape ships under a new version.

project_idstring uuid nullable required

The project the event belongs to; null for team-scoped and billing events.

Response

Your endpoint acknowledged the delivery. Any 2xx status within 30 seconds marks it delivered; the response body is ignored.

Changes

Webhooks have no change history: a webhook is keyed by its event name rather than a path and method, so no recorded change can name it.