generated: '2026-08-12'
method: searched
source: https://knowledgebase.constantcontact.com/lead-gen-crm/articles/KnowledgeBase/50234-Using-Postback-URLs?lang=en_US
spec_type: none
note: >-
  SharpSpring publishes no AsyncAPI document and has no webhook subscription API — there is no
  createWebhook/listWebhooks method anywhere in the published method surface. What it does have is
  "Postback URLs": an outbound HTTP push configured by a human in the UI, either on a form (Settings
  tab > Lead Status > Postback URL) or as an automation action ("post back lead info" / "account post
  back" under Notifications). The payload is sent as multipart/form-data, not JSON, which is unusual
  for an event surface and means consumers cannot validate it against a schema. Retry behaviour,
  timeouts, delivery guarantees, signing and replay protection are all undocumented. This artifact
  records the event surface honestly as a webhook catalog; it is deliberately NOT wired as AsyncAPI,
  because no AsyncAPI document exists.
event_surface:
  kind: outbound postback
  subscription_api: false
  configuration: per-form and per-automation-step, in the application UI
  transport: HTTP
  encoding: multipart/form-data
  signing: none documented
  retries: not documented
  delivery_guarantee: not documented
  replay: not available
webhooks:
- name: form-submission-postback
  trigger: a contact completes and submits a Lead Gen & CRM native form
  configured_at: form Settings tab > Lead Status dropdown > Postback URL
  encoding: multipart/form-data
  fields:
  - emailAddress
  - firstName
  - lastName
  - leadID
  - accountid__sb
  - formid__sb
  - trackingid__sb
  - field_<id>
  - referrer
  - agent referrer
  - css url
  - recaptcha response
  note: >-
    field_<id> keys carry the account's custom fields; the __sb-suffixed keys are SharpSpring's
    internal form/account/tracking identifiers.
- name: automation-lead-postback
  trigger: a lead meets the trigger conditions of a visual automation workflow
  configured_at: automation > +Add > Action > Notifications > "post back lead info" > "to this URL"
  encoding: multipart/form-data
  payload: lead record fields, including custom fields
- name: automation-account-postback
  trigger: an account meets the trigger conditions of a visual automation workflow
  configured_at: automation > +Add > Action > Notifications > "account post back" > "to this URL"
  encoding: multipart/form-data
  payload: account record fields
related_api_methods:
- subscribeToLeadUpdates
- getEventsbyType
- getEmailEvents
- getEmailSendEvents
- getLeadTimeline
note_on_polling: >-
  Because there is no subscription API, most integrations built on this platform poll the
  *DateRange methods (getLeadsDateRange, getAccountsDateRange, getOpportunitiesDateRange,
  getCampaignsDateRange, getDealStagesDateRange, getOpportunityLeadsDateRange) on an interval and
  reconcile against updateTimestamp, rather than consuming events.
x-evidence:
  fetched: '2026-08-12'
  probes:
  - url: https://knowledgebase.constantcontact.com/lead-gen-crm/articles/KnowledgeBase/50234-Using-Postback-URLs?lang=en_US
    status: 200
  - url: https://knowledgebase.constantcontact.com/lead-gen-crm/articles/KnowledgeBase/50564-Understanding-Lead-Gen--CRM-Open-API-Methods?lang=en_US
    status: 200
  - url: https://api.sharpspring.com/asyncapi.yaml
    status: 307
    note: redirects to the login shell — no AsyncAPI document served