Hi Sean,

That’s a good question — what you’re seeing is the normal behavior of the default package in Odoo. The Easypost connector in Odoo 17 always needs at least one package with dimensions, otherwise the API will reject the request. If you only configure the default package, Odoo will use those dimensions for all shipments, regardless of the product.

To handle different box sizes you have a couple of options:

1. Define multiple packages in Inventory → Configuration → Packages

• Create multiple package types with the real dimensions (e.g., Small Box, Medium Box, Large Box).
• When creating a delivery, choose the correct package size before validating.
• Odoo will then send those dimensions to Easypost and you’ll get the right rates.

2. Use product-specific packaging

• On the product form, under Inventory → Packaging, you can define one or more packaging options with dimensions.
• When you sell that product, Odoo can automatically suggest the correct package if you configure the shipping rules accordingly.

3. Automate package selection (customization)

Out-of-the-box, Odoo won’t automatically pick the right package for you — you need to select it. If you want it to be automatic (e.g., based on product weight, volume, or quantity), you’ll need a small customization that maps products to package types at delivery order creation.

- In short: the default package is just a fallback. For proper quotes, you’ll want to maintain a set of package types in Odoo and use them when confirming shipments.

Hope this helps..