Pattern: 1) Zapier trigger on product event → fetch user/profile data. 2) Build a prompt template with variables + 1–2 examples; ask ChatGPT to return strict JSON {subject, preheader, body_html}. 3) Call ChatGPT API (POST /v1/chat/completions) with temperature 0.2 and max_tokens; validate & sanitize. 4) Map JSON to your ESP via Zapier action/webhook, add error handling and retries.

API tips: ask for JSON-only output, check token budget, truncate long inputs, keep few-shot examples minimal.

See ChatGPT integration notes: Compare ChatGPT and Gemini