Chris asks Is there any way to add custom line items to the cart from the front end of the store (as opposed to using the admin API)?
While it's easy to add custom line item properties to existing products and variants from the product form (by including an additional properties field on the product form) there's no way to add a completely custom product.
If you find yourself in this situation it seems your best option is to reach for an off the shelf app such as Infinite Options or spin up a quick private app to use the API directly.
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