Pagesnap Webhooks

generated: '2026-09-02'
method: searched
source: https://pagesnap.142-93-197-141.sslip.io/docs
asyncapi_spec: null
asyncapi_note: >-
  Pagesnap publishes no AsyncAPI document. Probed /asyncapi.json and /asyncapi.yaml alongside the
  OpenAPI discovery sweep; the spec itself declares an empty `webhooks` object and no callbacks.
  The event surface below is documented in prose and in the Monitor schema, so it is captured as a
  webhook catalog rather than fabricated as an AsyncAPI file.
surface: outbound-webhook
scope: change monitors only
subscription:
  operation_id: createMonitor
  field: webhook_url
  constraints: https?:// URL, max 4096 chars, must pass the same public-address policy as a monitored target
  auth_required: true
security:
  signature_header: X-Pagesnap-Signature
  algorithm: 'sha256=<hex HMAC-SHA256>'
  signed_over: the exact JSON request body, including its timestamp
  secret_delivery: >-
    webhook_secret is returned exactly once, in the createMonitor 201 response (MonitorWithSecret).
    listMonitors deliberately omits it and there is no rotation or re-reveal operation.
  verification_guidance: >-
    Verify the exact raw bytes with a constant-time comparison BEFORE parsing, then reject
    timestamps outside your replay window.
delivery:
  timeout_seconds: 10
  retries: 3 after the initial attempt
  redirects_followed: false
  response_body: discarded
  address_policy: The destination is re-resolved on every attempt against the same SSRF policy as monitored targets.
  disable_rule: >-
    After 20 consecutive failed change deliveries the webhook is disabled and the monitor records
    a generic note. The monitor itself stays active.
native_integrations:
  - Slack (injection-safe native payload)
  - Discord (injection-safe native payload)
events:
  - name: monitor.change
    trigger: >-
      A scheduled or manual monitor check detects a change above threshold_percent in text, visual
      or meta mode.
    modes: [text, visual, meta]
    intervals: ['1h', '6h', '24h']
    payload_schema: null
    payload_note: >-
      The provider documents the signing scheme, delivery semantics and failure behavior but does
      not publish the change-notification body schema. Recorded as null rather than guessed.
poll_alternatives:
  - operation_id: getMonitor
    note: Returns the monitor plus recent check results - the pull equivalent of the webhook.
  - operation_id: checkMonitor
    note: Runs a check immediately.
  - operation_id: getCrawlJob
    note: >-
      Asynchronous crawl and llms-txt jobs have NO webhook; completion is discovered by polling
      status_url. This is the one place where a callback would help and none is offered.