ShipGrid lets merchants upload carrier Excel rate tables to generate multi-zone shipping rates with weight tiers. Connect multiple carriers to Shopify locations, apply tag-based filtering, and add surcharges or discounts. Handle mixed-cart scenarios with rules that apply automatic per-item supplements for small items shipped alongside larger orders. A built-in rate tester simulates carts and shows which carriers activate. Rate History logs every checkout request.

• Upload carrier Excel sheets to auto-create zones and weight-based rate tiers
• Mixed cart and multi-location support with per-item surcharge rules
• Rate tester simulates real carts to show which carriers activate and why
• Rate History logs every checkout request with full trace for troubleshooting
• Tag-based and location-based carrier filtering with dynamic rules