Challenge 2: Design a task.completed Webhook — Possible Solution
====================================================================

POST https://integrator-app.com/webhooks HTTP/1.1
Content-Type: application/json
X-Signature: t=1717003600,v1=f2a9d81b...

{
  "id": "evt_9c31",
  "type": "task.completed",
  "data": { "taskId": 501, "completedAt": "2026-07-06T14:32:00Z" }
}

WHY THIS WORKS AS AN ANSWER
------------------------------
This follows the exact shape the chapter's task.updated example
established, changed only where it genuinely needs to differ:
  - The X-Signature header is present in the same "t=...,v1=..."
    format, since EVERY webhook the platform sends needs to be
    signed the same way, regardless of event type — signature
    verification isn't specific to one kind of event.
  - "id" is a fresh, unique event identifier ("evt_9c31", distinct
    from the earlier "evt_88f2") — every individual event needs its
    OWN id for deduplication purposes, even if it's logically related
    to the same task.
  - "type" is changed to "task.completed" to reflect what actually
    happened, which is the whole reason a receiver would need to
    distinguish this event from a task.updated or task.created event
    in the first place.
  - "data" is adapted to include a "completedAt" timestamp rather
    than just a status field, since "when was it completed" is more
    directly useful information for this SPECIFIC event type than
    repeating a generic status string.

The receiver would verify X-Signature and deduplicate on "evt_9c31"
using the exact same logic as any other webhook event — nothing about
the verification or deduplication process changes based on event
type, only the payload shape reflects what's specific to what
happened.