billing.* events

The creator downgrades to a lower Subscriby tier.

When this fires

The creator switches their Subscriby subscription to a lower tier. The change lands at the end of the period they have already paid for, not at effective_at: the current phase runs to its existing end date and the lower tier begins after it.

Caveats

  • effective_at is stamped at emission time and is never in the future, even when the provider defers the billing change to the next renewal boundary. Do not use it to schedule feature revocation.
  • Tier-locked features (Teams, custom roles, etc.) may become read-only or hidden once the current paid period ends, never at effective_at.

Related events

  • billing.tier_upgraded: opposite direction.
  • billing.tier_cancelled: terminal downgrade path.
postWebhookbilling.tier_downgraded

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'billing.tier_downgraded' required

The event name, always billing.tier_downgraded 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.