For our regular private app I could get available shipping rates by using GraphQL Admin API - draftOrderCalculate mutation - https://shopify.dev/docs/admin-api/graphql/reference/orders/draftordercalculate#interactive-example-2020-01 :
Query POST https://jennyyoo-staging.myshopify.com/admin/api/2020-01/graphql.json :
mutation draftOrderCalculate($input: DraftOrderInput!) {
draftOrderCalculate(input: $input) {
calculatedDraftOrder {
subtotalPrice
totalPrice
totalShippingPrice
totalTax
availableShippingRates {
handle
title
price {
amount
}
}
}
userErrors {
field
message
}
}
}
Input:
{
"input": {
"lineItems": [{
"variantId": "gid://shopify/ProductVariant/123",
"quantity": 1,
"appliedDiscount": null
}],
"shippingAddress": {
"firstName": "Eduard",
"lastName": "...",
"address1": "...",
"address2": "...",
"phone": "123",
"city": "Miami",
"countryCode": "US",
"provinceCode": "FL",
"zip": "123"
},
"billingAddress": {
"firstName": "Eduard",
"lastName": "...",
"address1": "...",
"address2": "...",
"phone": "123",
"city": "Miami",
"countryCode": "US",
"provinceCode": "FL",
"zip": "123"
},
"email": "eduard@example.com"
}
}
Response:
{
"data": {
"draftOrderCalculate": {
"calculatedDraftOrder": {
"subtotalPrice": "285.00",
"totalPrice": "319.20",
"totalShippingPrice": "0.00",
"totalTax": "34.20",
"availableShippingRates": [
{
"handle": "shopify-USPS%20First%20Class%20Mail-2.75",
"title": "USPS First Class Mail",
"price": {
"amount": "2.75"
}
},
{
"handle": "shopify-Fedex%20Home%20Delivery-9.95",
"title": "Fedex Home Delivery",
"price": {
"amount": "9.95"
}
},
{
"handle": "fedex-FEDEX_EXPRESS_SAVER-22.67",
"title": "FedEx FedEx Express Saver®",
"price": {
"amount": "22.67"
}
},
{
"handle": "fedex-FEDEX_2_DAY-30.84",
"title": "FedEx FedEx 2Day®",
"price": {
"amount": "30.84"
}
},
{
"handle": "fedex-STANDARD_OVERNIGHT-46.24",
"title": "FedEx FedEx Standard Overnight®",
"price": {
"amount": "46.24"
}
}
]
},
"userErrors": []
}
},
"extensions": {
"cost": {
"requestedQueryCost": 11,
"actualQueryCost": 11,
"throttleStatus": {
"maximumAvailable": 2000.0,
"currentlyAvailable": 1989,
"restoreRate": 100.0
}
}
}
}