generated: '2026-07-26'
method: searched
source: openapi/alto-api-openapi.json + developers.vebraalto.com + developers.zoopla.co.uk +
  live probes
summary: >-
  Alto and Zoopla publish good contracts and almost no lifecycle commitments. There is no
  versioning scheme in any URL, no deprecation policy, no Sunset/Deprecation header support, no
  SLA, and no status page on any host in the estate. The only lifecycle signals that exist are
  one deprecated operation inside the Alto OpenAPI, a 6-hour/10-attempt webhook retry window,
  and a 30-day lead retention limit.
versioning:
  scheme: none
  alto:
    spec_version: '1.0'
    url_versioning: false
    note: Alto resources sit at the host root (/contacts, /inventory, /tenancies). Environment
      is selected by host — api.alto.zoopladev.co.uk (sandbox) vs api.alto.zoopla.co.uk
      (production) — not by version.
  zoopla:
    leads:
      spec_version: '0.1'
      spec_format: Swagger 2.0
    premium_listings:
      spec_version: 1.0.0
    weekly_featured_property:
      spec_version: 1.0.0
    url_versioning: false
    note: All three Zoopla product APIs share the services.zoopla.co.uk host with product-named
      path prefixes (/products/premium-listings, /products/weekly-featured-properties,
      /applicant-leads).
  legacy_generation:
    note: >-
      A separate, older "Vebra Alto API" generation (v12/v13, an XML property feed on
      webservices.vebra.com / api.vebra.com) is still referenced by third-party CMS connectors.
      Both hosts return 403 to anonymous probes and neither is documented on
      developers.vebraalto.com. Recorded as observed context, not as a supported surface.
deprecation:
  policy_url: null
  policy_published: false
  sunset_header: false
  deprecation_header: false
  rfc8594: false
  notice_period: none published
deprecated_operations:
- operation: openapi/alto-api-openapi.json#GET /clients
  deprecated: true
  scope: alto/route:get-clients
  notice: This endpoint is now obsolete. Use /contacts endpoint instead.
  removal_date: not published
  replacement: GET /contacts
compatibility_promise:
  webhooks: >-
    "We may add fields to the payload over time. Ignore any fields you do not recognise rather
    than failing." — https://developers.vebraalto.com/guides/webhooks/. The only forward-
    compatibility commitment published anywhere in the estate.
  api: none published
sla:
  url: null
  uptime_target: not published
  note: The API Terms of Use (https://developers.vebraalto.com/api-terms-of-use) bind API use to
    an existing contract with Vebra Solutions; any availability commitment lives in that private
    contract, not on the public surface.
status_page:
  exists: false
  probed:
  - url: https://status.altosoftware.co.uk
    result: redirects to the id.vebraalto.com Auth0 login — this is the Alto application login,
      not a status page
  - url: https://status.zoopla.co.uk
    result: resolves to www.zoopla.co.uk behind a Cloudflare interstitial (403)
  - url: https://status.vebraalto.com
    result: NXDOMAIN
  - url: https://altosoftware.statuspage.io
    result: redirects to atlassian.com/software/statuspage — unclaimed
  - url: https://zoopla.statuspage.io
    result: redirects to atlassian.com/software/statuspage — unclaimed
  - url: https://status.houseful.co.uk
    result: NXDOMAIN
retention_and_windows:
  zoopla_leads:
    retention: 30 days
    default_query_window: last 24 hours
    push_retry_window: 24 hours, then leads are retained a further 29 days with no automatic
      replay mechanism
    source: https://developers.zoopla.co.uk/leads/docs/available-lead-services
  alto_webhooks:
    retry_attempts: 10
    retry_window: 6 hours
    after_window: the notification is never retried again
    source: https://developers.vebraalto.com/guides/webhooks/
release_notes:
  api: none
  product: https://files.vebraalto.com/alto/downloads/ (unindexed PDFs)
  artifact: changelog/alto-vebra-changelog.yml
onboarding_lifecycle:
  stages:
  - Register an integration in Alto Connect (https://connect.vebraalto.com/connect) under an
    existing Vebra Solutions contract.
  - Receive sandbox credentials and an Alto test environment login by email.
  - An individual agency activates the integration; Alto emails the partner the AgencyRef.
  - Webhook subscriptions are configured manually by Alto on request to
    connectsupport@altosoftwaregroup.co.uk.
  source: https://developers.vebraalto.com/guides/activation-request-emails/
  api_operations:
  - GET /partners/integration — read the integration activation state
  - POST /partners/integration/status — update the integration activation state
  - GET /opt-out-status/{linkedType}/{linkedId} — read a subject's integration opt-out status
  note: Activation and deactivation are also emitted as webhook events (Integration.Enabled,
    Integration.Disabled, Integration.Activated, Integration.Deactivated), which makes the
    partner lifecycle the one part of this estate that IS machine-observable.
gaps:
- No status page anywhere in the estate — a 6,000-agency CRM with no public availability signal.
- No deprecation policy, no Sunset/Deprecation headers, no removal date on the one deprecated
  operation.
- No URL versioning, so a breaking change has no compatible landing place.
- No published SLA on the anonymous surface.