Send 10-day post-purchase WhatsApp offers with Odoo, OpenAI and Evolution API

What Problem Does It Solve?

Generic, automated retention messages often feel like spam and fail to engage returning customers. Manually tracking which customers ordered exactly 10 days ago to send them tailored offers is extremely time-consuming. Sending bulk promotional WhatsApp messages too quickly can result in phone number bans. This workflow solves these issues by: Automatically fetching customers from Odoo whose invoices are exactly 10 days old. Using an AI Agent (OpenAI) to generate a highly personalized, warm Egyptian Arabic message for each customer. Offering a targeted 10% extra discount to encourage repeat purchases via social media platforms. Implementing a 1-minute "Wait" mechanism between messages to protect your WhatsApp account from being flagged.

How to Configure It

Odoo Setup Connect your Odoo credentials in n8n. The workflow fetches invoices starting from April 2026. Adjust the date filter in the "Fetch 10-Day Old Invoices" node if needed. OpenAI Setup Add your OpenAI API key to the "Generate AI Message" node. You can tweak the system prompt to match your specific brand voice or adjust the discount offer. WhatsApp API Setup This workflow uses the Evolution API. Update the URL and "apikey" in the "Send WhatsApp Discount" node with your specific instance details.

How It Works

Every day at 10:01 AM, the schedule node triggers the workflow automatically. It queries Odoo for all posted invoices exactly 10 days old and retrieves the corresponding customer contact details (Name and Phone). It processes the customers one by one through a loop (Split In Batches). For each customer, OpenAI generates a unique, friendly colloquial Arabic message calling them by their first name and offering a 10% discount. The message explicitly directs the customer to claim the offer via social media messages, completely avoiding formal "terms & conditions" jargon. The workflow sends the AI-generated text via WhatsApp and then pauses for 1 minute before processing the next customer.

Customization Ideas

Change the AI prompt to offer different discounts based on the total amount the customer spent in their last order. Add a condition to skip customers who have already made a new purchase within the last 10 days. Switch the AI model to Claude or Gemini depending on your preference for Arabic copywriting.

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