Klaviyo

Klaviyo pulls your full store catalog and order history into its segmentation engine, so you can build a list of "customers who bought Product A but not Product B in the last 60 days" without writing a query. Prebuilt flows cover abandoned cart, browse abandonment, post-purchase, and win-back sequences, and predictive analytics estimate a customer's lifetime value and next order date to steer who gets a discount versus a full-price nudge.

Klaviyo bills by active profiles rather than by send volume, a change it moved to in 2025: the free plan covers 250 profiles and 500 sends a month, the entry paid tier runs about $20 a month for 500 contacts and 5,000 emails, and costs rise to roughly $150 at 10,000 profiles, $720 at 50,000, and beyond $2,000 a month at 100,000-plus. SMS is metered separately through credit packs rather than folded into the flat fee. It's the strongest choice here for a store with real order volume that wants deep behavioral segmentation, and probably more platform than a brand-new store with a few hundred customers needs yet.