As of December 2025, businesses can utilise custom audiences within ChatGPT through integrations with major Customer Data Platforms (CDPs) and marketing automation tools, primarily via the OpenAI API and partner platforms like HubSpot, Salesforce Marketing Cloud, and ActiveCampaign – all commonly used by Australian SMEs.

This functionality doesn’t involve directly *uploading* customer lists to ChatGPT due to privacy regulations like the Australian Privacy Principles (APPs). Instead, businesses connect their existing CDP or marketing platform. These platforms then send anonymised, aggregated audience segments – defined by attributes like purchase history, website behaviour, or demographics – to ChatGPT via secure API calls. ChatGPT then uses these segment definitions to tailor responses within applications like custom chatbots or content generation. Currently, OpenAI’s API now includes enhanced data governance features to ensure compliance with Australian data residency requirements. In 2026, we anticipate further integration with Australian-specific marketing platforms like Campaign Monitor and Mailchimp, offering more streamlined connections. The cost is determined by API usage, typically calculated per token, and varies depending on the chosen platform and data volume.

Essentially, custom audiences in ChatGPT function by leveraging existing marketing infrastructure to provide contextual information, rather than directly handling Personally Identifiable Information (PII).