All Kiwi data below comes from its public Shopify App Store listing and website, checked on July 26, 2026. Listings change; if something is outdated, tell us and we'll correct it.
At a glance
| FitKit | Kiwi Size Chart & Recommender | |
|---|---|---|
| Track record | New app (launching 2026) | Category leader — years on the App Store, large review base |
| Storefront weight | 4.8 KB gzipped, lazy-loaded on first click of the Size guide link — zero network requests at page load (config read from a metafield) | Loads app assets on product pages; no published weight figure — audit with Lighthouse on your own store |
| Size recommender | Rule-based: visitor enters 2–3 measurements, matched against your chart's ranges — instant, no AI, nothing sent to a third party (Pro) | Mature AI/ML-powered recommender, marketed as a core feature |
| Pricing | Free (1 guide) · Growth $6.99/mo · Pro $19.99/mo — 14-day trial on paid plans | Free plan plus paid tiers; higher tiers cost more than FitKit's Pro |
| Chart building | Free table builder (rows/columns, size/measurement/text cells), 6 preloaded templates, guide image upload (500 KB max) | Chart builder with templates and import options |
| CSV import | Not in V1 | Import options available |
| Unit switch | Automatic cm/inches toggle; default unit follows visitor locale (US = inches) | Unit conversion supported |
| Assignment | Product, tag, collection, vendor or global — clear priority: product > tag > collection > vendor > global | Flexible assignment options |
| Translations | EN/FR/DE/ES automatic by visitor locale (Growth+) | Localization supported |
| Analytics | Guide opens + add-to-cart rate after open, per product (Pro). No revenue attribution — add-to-cart is the honest proxy | Reporting available |
| Data & privacy | Single read_products scope; no personal data collected, anonymous daily counters only | See their privacy policy |
Where Kiwi is stronger
- Track record and trust. Kiwi has been the reference in this category for years, with a large review base. FitKit is new and hasn't earned that history yet — that's a real factor, and we won't pretend otherwise.
- AI recommender maturity. Kiwi's recommender is a long-standing, actively developed feature. If your sizing is complex or non-standard, or you want recommendations from minimal visitor input, it can go further than a rules engine.
- Feature depth and integrations. Chart imports, more layout options, and integrations built up over years. FitKit deliberately ships a smaller, focused feature set in V1 — no CSV import, for example.
- Large catalogs with edge cases. Stores with thousands of products and unusual sizing logic will find more knobs to turn in Kiwi.
Where FitKit is stronger
- Storefront weight you can measure. FitKit injects nothing at page load: the Size guide link is rendered by the theme block, the guide config lives in a metafield, and the modal script (4.8 KB gzipped) loads only when a visitor clicks. Zero network requests before that click, zero impact on Core Web Vitals. Run Lighthouse before and after installing — that's the test we designed for.
- Price. Unlimited guides, all templates, advanced assignment and full customization at $6.99/month; the recommender and analytics at $19.99/month. For most stores the same job costs less.
- A recommender you can explain. The visitor's 2–3 measurements are matched against the ranges in your own chart. Instant answer, fully deterministic, auditable by reading the chart — and because there is no AI, there is no per-request cost we'd have to pass on to you, and no visitor data leaves the page.
- 3-minute setup. Pick a template, adjust the numbers, assign it to a tag or collection — done. Six templates cover men's/women's t-shirts, pants, shoes (EU/US/UK), rings and kids, with ready-made "how to measure" illustrations.
Our honest verdict: if you want an AI-powered recommender, chart imports, and the deepest feature list in the category — and pricing is secondary — choose Kiwi Size Chart & Recommender; its track record is real. If what you want is a beautiful size chart that adds literally nothing to your page load, a measurement-based recommender you can explain to yourself, and a lower bill, choose FitKit. Both have free plans, so testing costs you nothing.