Flatto is a Tokyo-based Shopify development company whose services include public Shopify apps, custom app development, and technical consulting. The most complete product found in the collected materials is “チェックアウト住所バリデーター,” a Shopify checkout address validation app. It is designed for Japanese e-commerce scenarios, detecting address errors in real time before customers submit orders, thereby reducing failed shipping label generation and manual follow-up.
The app checks whether postal codes and addresses match, identifies non-existent Japanese postal codes, missing street numbers, address length issues, NG words, full-width numerals, special hyphens, and more—all in real time on the checkout page. Its value is not as a “developer IDE”-style tool, but as merchant operations automation built around Shopify Checkout Extensibility. Flatto also showcases apps for consent checkboxes, hiding/sorting/renaming payment methods, hiding/sorting/renaming shipping methods, including cash-on-delivery fees, and discounts based on customer tags and product tags. Its ecosystem is clearly centered on Shopify checkout, payments, shipping, and promotions.
The address validation app uses an order-volume-based subscription model: Free is $0/month for up to 100 orders; Standard is $17.99/month for up to 1,000 orders; Growth is $39.99/month for up to 5,000 orders; Enterprise is $99.99/month with unlimited orders. All tiers include the same features; if the order limit is exceeded, the feature is temporarily disabled and no overage fees are charged. The installation flow is also straightforward: install from the Shopify App Store, enable validation rules in the admin interface, and the rules automatically take effect on the checkout page. For small Japanese stores, the trial barrier is low.
The advantages are its focused problem scope, transparent pricing, a free tier that does not cripple features, and Built for Shopify certification. The company also claims experience developing and operating more than 10 Shopify apps, and its App Store products have received many five-star reviews. The downsides are that the public materials are mainly merchant-facing explanations and blog posts; there is no visible API/SDK, open-source option, self-hosting, SLA, or detailed developer documentation. The address rules are clearly Japan-oriented, and support for addresses in other countries is unclear. Pricing and delivery models for custom development and technical consulting are also not disclosed.
It is best suited for Shopify merchants shipping to Japanese consumers who frequently encounter address errors with Yamato B2 Cloud or Sagawa e飛伝Ⅲ. It is also relevant for teams looking to customize checkout payment or shipping rules. Mainland China access, payment methods, and localization support are not stated in the main materials, so they should be considered unknown. If access or payment is restricted, alternatives include other address validation plugins on the Shopify App Store, custom development through a Shopify Partner, or local service providers.
⚠ This review is compiled from public sources and does not constitute a purchase recommendation. Verify all facts on the vendor's official site. Verify on flatto.dev official site.
flatto.dev is an Japan Dev Tools provider. TG4G tracks its product information, an overall rating of 7.0/10, and a China-accessibility score of Workable. Click "Visit Official Site" to reach flatto.dev directly.