Webhook payload

Every delivery is a POST with a JSON body — the envelope — and a fixed set of X-Weelkit-* headers. The envelope carries the authoritative persisted article version exactly as it was generated; Weelkit never re-renders content at delivery time.

Envelope

{
  "protocolVersion": "weelkit-webhook.v2",
  "eventId": "7b1e9f4a-6c2d-4e8f-9a3b-1c5d7e9f0a2b",
  "operationId": "3f8c2d1e-9a7b-4c6d-8e2f-0b4a6c8d1e3f",
  "eventType": "article.version.created",
  "occurredAtUtc": "2026-08-13T10:15:00Z",
  "organizationId": "d4c3b2a1-...",
  "contract": { "schemaVersion": "article-output.v3", "schemaFingerprint": "weelkit-platform-article.v3+org.abcdef0123456789", "contractVersion": 3, "canonicalCatalogVersion": 3 },
  "article": { "articleId": "...", "articleVersionId": "...", "versionNumber": 3, "title": "...", "contentHtml": "<p>...</p>", "excerpt": "...", "urlSlug": "...", "seoTitle": "...", "metaDescription": "...", "coverImageUrl": null, "categories": ["..."], "tags": ["..."], "ogTitle": null, "ogDescription": null, "ogImageUrl": null, "customFields": { "campaignFocus": "Q3 launch" }, "createdAtUtc": "2026-08-13T10:14:58Z" }
}

Envelope fields

string

Always weelkit-webhook.v2 for this protocol version.

string (UUID)

Identifies the event. Stable across retries of the same delivery.

string (UUID)

Stable operation identity for the delivery. Retries reuse it — deduplicate by this value. See Signature verification.

string

article.version.created for article deliveries, webhook.test for connection tests.

string (ISO 8601)

When the event occurred, in UTC.

string (UUID)

The organization the article belongs to.

object

Identifies the exact contract the article version was generated against.

Show contract properties

string

The envelope’s article schema version, article-output.v3.

string

The effective contract fingerprint starts with weelkit-platform-article.v3. Changed canonical field selections add +sel.<16 hex>, active custom fields add +org.<16 hex>, and changed field properties add +prop.<16 hex>. Selection and property suffixes can appear without custom fields. See Organization article fields.

number

Version of the compiled article output contract.

number

Version of the immutable canonical field catalog.

object | null

The persisted article version. null for webhook.test events — handle that case before dereferencing.

Show article properties

string

Stable identifier of the article across versions.

string

Identifier of this exact persisted version.

number

Monotonically increasing version number within the article.

string

Article title.

string

Full article body as a sanitized semantic HTML fragment. It is not a complete HTML document.

string | null

Short excerpt.

string | null

URL slug.

string | null

Meta title.

string | null

Meta description.

string | null

Cover image URL, when one is set. The envelope carries the URL only, not the cover image’s alt text. Images inside contentHtml keep their own alt attributes.

array of string

Categories. Empty array when none are set.

array of string

Tags. Empty array when none are set.

string | null

Open Graph title, when explicitly enabled and generated.

string | null

Open Graph description, when explicitly enabled and generated.

string | null

Open Graph image URL, when explicitly selected or mapped.

object

Organization custom field values keyed by field key. Empty object when the organization has no active custom fields. See Organization article fields.

string (ISO 8601)

When this article version was persisted, in UTC.

Test event

Send test delivers the same envelope and headers with eventType set to webhook.test and article set to null:

{
  "protocolVersion": "weelkit-webhook.v2",
  "eventId": "7b1e9f4a-6c2d-4e8f-9a3b-1c5d7e9f0a2b",
  "operationId": "3f8c2d1e-9a7b-4c6d-8e2f-0b4a6c8d1e3f",
  "eventType": "webhook.test",
  "occurredAtUtc": "2026-08-13T10:15:00Z",
  "organizationId": "d4c3b2a1-...",
  "contract": { "schemaVersion": "article-output.v3", "schemaFingerprint": "weelkit-platform-article.v3", "contractVersion": 3, "canonicalCatalogVersion": 3 },
  "article": null
}

Fingerprint examples

These examples have no custom fields.

fingerprint-examples

[
  {
    "id": "untouched",
    "customFieldCount": 0,
    "defaultFieldSelections": {},
    "propertySelections": {},
    "schemaFingerprint": "weelkit-platform-article.v3"
  },
  {
    "id": "selection",
    "customFieldCount": 0,
    "defaultFieldSelections": {
      "excerpt": false
    },
    "propertySelections": {},
    "schemaFingerprint": "weelkit-platform-article.v3+sel.5503e7e99ecb14b5"
  },
  {
    "id": "property",
    "customFieldCount": 0,
    "defaultFieldSelections": {},
    "propertySelections": {
      "coverImage.caption": true
    },
    "schemaFingerprint": "weelkit-platform-article.v3+prop.6ecc058eea423d1f"
  },
  {
    "id": "selection-and-property",
    "customFieldCount": 0,
    "defaultFieldSelections": {
      "excerpt": false
    },
    "propertySelections": {
      "coverImage.caption": true
    },
    "schemaFingerprint": "weelkit-platform-article.v3+sel.5503e7e99ecb14b5+prop.6ecc058eea423d1f"
  }
]

Headers

Header	Value
`X-Weelkit-Signature`	`v1=` followed by hex HMAC-SHA256 over `{timestamp}.{raw body}`
`X-Weelkit-Timestamp`	Unix timestamp in seconds used in the signature
`X-Weelkit-Event`	The event type, e.g. `article.version.created`
`X-Weelkit-Event-Id`	The envelope’s `eventId`
`X-Weelkit-Operation-Id`	The envelope’s `operationId` — stable across retries
`X-Weelkit-Protocol-Version`	`weelkit-webhook.v2`
`User-Agent`	`Weelkit-Webhooks/2`
`Content-Type`	`application/json`

Verify the signature before parsing the body — see Signature verification.

Publishing overview

WordPress

WordPress.com

Sanity

Ghost

API webhook

Custom API

Webhook payload

Envelope

Envelope fields

Test event

Fingerprint examples

Headers

​Envelope

​Envelope fields

​Test event

​Fingerprint examples

​Headers

Envelope

Envelope fields

Test event

Fingerprint examples

Headers