generated: '2026-08-26'
method: searched
source: https://docs.developers.optimizely.com/content-marketing-platform/docs/backward-compatibility-1
api: Optimizely CMP Open API v3
versioning:
  style: URI path major version
  current: v3
  base: https://api.cmp.optimizely.com/v3
  history:
  - version: v3
    host: https://api.newscred.com/v3
    status: legacy host
    note: The original NewsCred-branded host. CMP still requires *.newscred.com in customer allowlists.
  - version: v3
    host: https://api.welcomesoftware.com/v3
    status: legacy host, documented as still functional
    since: '2021-03-28'
    note: >-
      The Welcome Open API spec states "From 28th March 2021, we are serving open API through
      https://api.welcomesoftware.com/v3 ... The previous base URL https://api.newscred.com/v3
      will remain functional as it used to be until any further notice."
  - version: v3
    host: https://api.cmp.optimizely.com/v3
    status: current
    note: The Optimizely-branded host after the December 2021 acquisition.
  docs: https://docs.developers.optimizely.com/content-marketing-platform/docs/domains-and-ip-address
backward_compatibility:
  policy_published: true
  docs: https://docs.developers.optimizely.com/content-marketing-platform/docs/backward-compatibility-1
  non_breaking_changes:
  - Add an endpoint or support for an HTTP method
  - Add a field to the response payload
  - Add an optional field to the request payload
  - Add support for an optional query parameter
  - Add a value to an enum
  - Add support for an optional request header
  - Add a response header
  webhook_non_breaking_changes:
  - Add a field to the webhook payload
  - Add a value to an enum
  - Add a request header
  webhook_docs: https://docs.developers.optimizely.com/content-marketing-platform/reference/get-started
  gap: >-
    The policy enumerates what CMP considers NON-breaking. It does not define what counts as
    breaking, does not commit to a notice period, and does not state how a breaking change would
    be announced.
deprecation:
  policy_published: false
  sunset_header: false
  deprecation_header: false
  rfc8594: false
  note: >-
    No deprecation or sunset policy is published, and neither the OpenAPI nor the docs mention
    RFC 8594 Sunset / Deprecation response headers. The only deprecation-shaped signal in the
    contract is the Experimental badge, which Optimizely describes as pre-release rather than
    end-of-life: "Experimental APIs are most often NOT operational and the documentation may
    change until the APIs are fully released." The concrete lifecycle facts that ARE published
    are the host migrations above, which were announced with an explicit
    remains-functional-until-further-notice commitment rather than a dated sunset.
  deprecated_operations_in_spec: 0
  deprecated_operations_source: openapi/newscred-cmp-open-api-openapi.json
  actual_deprecations_found:
  - surface: DAM asset picker (library picker) postMessage payload
    fields: [guid, alt]
    notice: 'Documented verbatim as "Deprecated. Will be removed after December 2025."'
    docs: https://docs.developers.optimizely.com/content-marketing-platform/docs/library-picker
    note: >-
      The only dated removal commitment found anywhere on the Newscred/Welcome/CMP developer
      surface, and it is on an embeddable component rather than the REST API. As of this pass
      (2026-08-26) that date has passed and the doc still lists the fields as deprecated rather
      than removed, so consumers cannot tell from the docs whether removal happened.
experimental:
  badge: Experimental
  docs: https://docs.developers.optimizely.com/content-marketing-platform/reference/api-reference
  note: >-
    A substantial share of the CMP surface — Fields, Workflows, Task Step, several Structured
    Content and Publishing operations, and the new Content Graph endpoints — carries the
    Experimental badge, meaning the shape may change without a version bump.
status_page:
  url: https://status.optimizely.com/
  status: 200
  scope: Optimizely platform-wide status, including Content Marketing Platform
sla:
  published: false
  note: No public uptime SLA or credit schedule for CMP was found on the developer or trust surfaces.
changelog: changelog/newscred-changelog.yml