Create custom audience

Create a custom audience. customer_list is supported on Meta, Google, X, LinkedIn, TikTok, and Pinterest; website and lookalike are Meta-only; company_list, engagement and website_retargeting are LinkedIn-only. saved_targeting stores a reusable TargetingSpec (no member upload, no adAccountId) that you reference later via savedTargetingId on POST /v1/ads/create.

How the audience gets filled depends on the type:

• customer_list is created empty. Add members with POST /v1/ads/audiences/{audienceId}/users. On TikTok and Pinterest the audience is provisioned lazily on that first upload (until then its status is pending).
• company_list is filled AT CREATION from the companies array below, which is required. To change the list afterwards send the new full list to POST /v1/ads/audiences/{audienceId}/companies (a replace, not a merge). The /users endpoint rejects these audiences with a 422.
• website, website_retargeting, engagement, meta_engagement and lookalike fill themselves from the pixel, engagement source or seed audience you point them at. They take no member upload at all.

Create is not idempotent, never auto-retry.