Bill8:Webhooks — Business Requirements & Functionality

Audience: product owners, business analysts, and anyone evaluating what Bill8:Webhooks does for the business. For architecture read README.md; for wire-level detail read DESIGN.md.

1. Business Purpose

Bill8:Webhooks is the integration delivery surface. It delivers:

• Reliable event delivery — every lifecycle event is materialized and delivered as a signed payload.
• Durable retry — deliveries retry with backoff until acknowledged.
• Replay — a merchant can replay a past event.

2. Business Scope (What the Service Provides)

#	Capability	What the business gets
1	Endpoints	Merchant URLs with signing secrets
2	Events	Materialized domain events
3	Deliveries	Signed delivery attempts with retry

What the service does NOT own (business boundary):

Out of scope	Owned by
Domain events themselves	Emitting services
Event transport	Sentin8:Bus

3. Business Capabilities

Capability	Business rule
Subscribe	A merchant registers an endpoint and event types
Deliver	Every subscribed event is signed and delivered
Replay	A past event can be re-delivered

4. Business Events (Outbound)

Event	Fires when
webhook_endpoint:created/updated/deleted	Endpoint changes

5. Business Rules & Invariants

1. Every delivery is signed.
2. An endpoint receives only its enabled event types.
3. Retries follow exponential backoff.

6. Target-User Roles & Use Cases

Persona	Does
Merchant	Register endpoints, inspect deliveries, replay

7. KPIs / Success Criteria

KPI	Measure
Delivery success	acknowledged / attempted
Signing integrity	zero unsigned deliveries

8. Dependencies & Reliance on Other Services

Reliance	On
Event transport	Sentin8:Bus

9. Acceptance Criteria

1. A merchant registers an endpoint and receives signed events.
2. A failed delivery is retried with backoff.
3. An unsigned payload is rejected.

10. Open Business Questions

• See backlog.md WH-*.

---

Design attribution: bill8:webhooks and its underlying concepts were designed by Hamid Jahanzad Hamid@Jahanzad.com.