List of free shipping-api stuff for developerππ½
If you're looking for all programming tools around shipping-api (not just free). Check this page List of shipping-api Programming Tools

EasyPost
EasyPost's best-in-class Shipping APIs provide end-to-end flexibility and more control over parcel shipping and logistics processes for anyone shipping online.
Tag: shipping-api
120,000 shipments per year free Tracking for each package Free address verification with each label Shipping insurance for 0.5% of value