Reorder Reminder — WhatsApp Retention SaaS

Consumable categories — pet food, supplements, cosmetics, cleaning products — have a repeat purchase built into them, and most stores pay to reacquire the same customer through ads instead of simply asking them to reorder.

Reorder Reminder automates that ask. It connects to ikas or Shopify, reads order history, infers each product's consumption cycle, and sends a WhatsApp message timed to land shortly before the customer runs out — with a direct path back to the basket. No app to install, no e-mail to ignore.

The engineering constraints are the interesting part: WhatsApp Business messaging is template-gated and rate-limited, so message templates, opt-out handling and send scheduling all have to be modelled properly rather than fired off ad hoc. Get that wrong and you lose the channel, not just the campaign.