Pre-select the right size.
Automatically. Every time.
Remember customer size and variant preferences across products, sessions, and devices.
Reduce friction and returns. Increase conversions and lifetime value.
The Problem
Customer buys a medium shirt. Comes back. Has to select medium again. Every. Single. Time.
Or worse: they guess wrong, order the wrong size, return it and maybe never come back.
Dumb.
Key Features
Cross Category Intelligence
32 waist jeans? We'll select 32 waist for all bottoms. Intelligently mapped by category.
Multi Device Sync
Sync preferences across multiple devices with Klaviyo, Attentive, Omnisend, or Postscript integrations.
Recommendation Algorithm
Prioritize past order data or recent add to cart data. Pre-select other variant options besides size.
Multi Option Support
Waist and length for pants. Chest and sleeve for dress shirts. Or pre-select other non-size variants.
Technical Callouts
Instant Preselection
Cached preferences load instantly, then sync with your purchase history for accuracy.
Works With 40+ Themes
Dawn, Debut, Brooklyn, Impulse, Prestige, and more — we've got selectors for them all. Custom theme? We have fallbacks.
How it learns a shopper's size
Three sources, in order of authority
Preferences are learned from what's currently in the cart, from past orders when the shopper is logged in, and from sizes they've selected while browsing. A more authoritative source overrides a weaker one.
Sizes are normalised first
One store can carry "M", "Medium" and "US M" across three suppliers. Sizes are normalised so a preference learned on one product still applies on another that labels it differently.
Category-aware, so it doesn't overreach
A shirt size is not a shoe size. Preferences are held per category, and correlations across categories are only used where they hold — a Medium top predicting a 32 waist, for example.
Smart Select questions
Does it work for shoppers who aren't logged in?
Yes. Guest shoppers get the full behaviour through browser storage, which persists for 365 days. No account and no login is required for it to work.
What if it pre-selects the wrong size?
The shopper selects the right one, and that selection immediately becomes the new preference. It never blocks a choice — it only changes which option starts selected.
Does it work with my theme?
It reads standard Shopify variant selectors, so it works on any product page using them. Themes with heavily custom variant pickers are the exception, and that's worth checking before you rely on it.
Can a shopper clear what it has learned?
Yes. Clearing site data in the browser resets stored preferences, and nothing is required from you to make that work — it's the standard browser control, not a setting buried in your store.
