Klaviyo offers Email AI and SMS AI tools that generate on-brand marketing copy — including subject lines and message body text — from a marketer's campaign goal prompt, providing multiple draft versions for review. These tools were included in the February 2024 Klaviyo AI launch and reached general availability in 2025.

In the Klaviyo email editor, a marketer describes their campaign goal (e.g., 'a 20% off flash sale on summer collection') and Email AI generates three draft emails with subject lines and body copy, informed by the brand's voice settings. SMS AI performs the same function for text message campaigns. The system uses OpenAI and AWS Bedrock for generative content, and Klaviyo's 'Brand Voice AI' feature allows brands to tune the model's output style to match their specific tone. Klaviyo confirms that external AI providers are contractually prohibited from using customer prompts to train their models.