Update README.md to use v3.0.0 function LowestShipmentRate instead of LowestRate (now private)

[lizziemac]

Description

When running the example from the README.md, I encountered the following error:

./main.go:59:28: client.LowestRate undefined (type *easypost.Client has no field or method LowestRate, but does have unexported method lowestRate)

Testing

The example works after changing the example to use LowestShipmentRate (see accordion for response). This is the extent of the testing I believe is required.

Output

lmaclean@Liz MacLean easypost-onboarding % go run main.go
{
"id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"object": "Shipment",
"mode": "test",
"created_at": "2026-05-13T13:57:10Z",
"updated_at": "2026-05-13T13:57:14Z",
"to_address": {
"id": "adr_a317d72f4ed311f194650022480c5359",
"object": "Address",
"mode": "test",
"created_at": "2026-05-13T13:57:10Z",
"updated_at": "2026-05-13T13:57:10Z",
"street1": "4000 Warner Blvd",
"city": "Burbank",
"state": "CA",
"zip": "91522",
"country": "US",
"name": "Bugs Bunny",
"phone": "8018982020",
"verifications": {}
},
"from_address": {
"id": "adr_a317d77f4ed311f194660022480c5359",
"object": "Address",
"mode": "test",
"created_at": "2026-05-13T13:57:10Z",
"updated_at": "2026-05-13T13:57:10Z",
"street1": "One Montgomery St",
"street2": "Ste 400",
"city": "San Francisco",
"state": "CA",
"zip": "94104",
"country": "US",
"company": "EasyPost",
"phone": "4155551212",
"verifications": {}
},
"return_address": {
"id": "adr_a317d77f4ed311f194660022480c5359",
"object": "Address",
"mode": "test",
"created_at": "2026-05-13T13:57:10Z",
"updated_at": "2026-05-13T13:57:10Z",
"street1": "One Montgomery St",
"street2": "Ste 400",
"city": "San Francisco",
"state": "CA",
"zip": "94104",
"country": "US",
"company": "EasyPost",
"phone": "4155551212",
"verifications": {}
},
"buyer_address": {
"id": "adr_a317d72f4ed311f194650022480c5359",
"object": "Address",
"mode": "test",
"created_at": "2026-05-13T13:57:10Z",
"updated_at": "2026-05-13T13:57:10Z",
"street1": "4000 Warner Blvd",
"city": "Burbank",
"state": "CA",
"zip": "91522",
"country": "US",
"name": "Bugs Bunny",
"phone": "8018982020",
"verifications": {}
},
"parcel": {
"id": "prcl_61b7ae08c2fe4caf9da3f9a28f1d47b0",
"object": "Parcel",
"mode": "test",
"created_at": "2026-05-13T13:57:10Z",
"updated_at": "2026-05-13T13:57:10Z",
"length": 10.2,
"width": 7.8,
"height": 4.3,
"weight": 21.2
},
"insurance": "100.00",
"rates": [
{
"id": "rate_fe2529b8475041aea92cdc4f580e025a",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "Priority",
"carrier": "USPS",
"carrier_account_id": "ca_483c76ed92204bb5877c7ceb1ab8044c",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "9.56",
"currency": "USD",
"retail_rate": "14.35",
"retail_currency": "USD",
"list_rate": "10.79",
"list_currency": "USD",
"delivery_days": 2,
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_9b24a7cdb6e14ddc9a669fdffa456892",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "GroundAdvantage",
"carrier": "USPS",
"carrier_account_id": "ca_483c76ed92204bb5877c7ceb1ab8044c",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "7.22",
"currency": "USD",
"retail_rate": "13.00",
"retail_currency": "USD",
"list_rate": "8.34",
"list_currency": "USD",
"delivery_days": 2,
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_2cd224714dc549d1aff4a3c235899823",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "Express",
"carrier": "USPS",
"carrier_account_id": "ca_483c76ed92204bb5877c7ceb1ab8044c",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "43.91",
"currency": "USD",
"retail_rate": "49.10",
"retail_currency": "USD",
"list_rate": "43.91",
"list_currency": "USD",
"delivery_days": 1,
"est_delivery_days": 1,
"billing_type": "easypost"
},
{
"id": "rate_fcdf7f77102e490582764cf3bbb0116d",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "UPSGroundsaverGreaterThan1lb",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "6.88",
"currency": "USD",
"delivery_days": 4,
"delivery_date": "2026-05-17T23:00:00Z",
"est_delivery_days": 4,
"billing_type": "easypost"
},
{
"id": "rate_ff7b887a2a734463a5d6e237632a14cd",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "NextDayAir",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "47.32",
"currency": "USD",
"retail_rate": "125.40",
"retail_currency": "USD",
"list_rate": "154.13",
"list_currency": "USD",
"delivery_days": 1,
"delivery_date": "2026-05-14T10:30:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 1,
"billing_type": "easypost"
},
{
"id": "rate_0d0d2bf470d54cb1987e98f939bdc9ef",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "NextDayAirEarlyAM",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "77.31",
"currency": "USD",
"retail_rate": "164.85",
"retail_currency": "USD",
"list_rate": "193.58",
"list_currency": "USD",
"delivery_days": 1,
"delivery_date": "2026-05-14T08:30:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 1,
"billing_type": "easypost"
},
{
"id": "rate_9a1224a608c046418bde71fd68f2babf",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "NextDayAirSaver",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "40.44",
"currency": "USD",
"retail_rate": "120.02",
"retail_currency": "USD",
"list_rate": "135.99",
"list_currency": "USD",
"delivery_days": 1,
"delivery_date": "2026-05-14T23:00:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 1,
"billing_type": "easypost"
},
{
"id": "rate_e8d92f968d7042229b742f2d7f48dd9c",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "2ndDayAir",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "13.96",
"currency": "USD",
"retail_rate": "40.24",
"retail_currency": "USD",
"list_rate": "46.06",
"list_currency": "USD",
"delivery_days": 2,
"delivery_date": "2026-05-15T23:00:00Z",
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_e848d218064d465eb7e99c7e126eebdf",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "2ndDayAirAM",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "16.21",
"currency": "USD",
"retail_rate": "46.55",
"retail_currency": "USD",
"list_rate": "53.52",
"list_currency": "USD",
"delivery_days": 2,
"delivery_date": "2026-05-15T10:30:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_29f7e8985d1543d887b85ae2ae1b6e5a",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "3DaySelect",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "13.11",
"currency": "USD",
"retail_rate": "31.20",
"retail_currency": "USD",
"list_rate": "34.15",
"list_currency": "USD",
"delivery_days": 3,
"delivery_date": "2026-05-18T23:00:00Z",
"est_delivery_days": 3,
"billing_type": "easypost"
},
{
"id": "rate_d0b674f7c26d46e7a72b3f8886d5eb05",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "Ground",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "7.68",
"currency": "USD",
"retail_rate": "16.10",
"retail_currency": "USD",
"list_rate": "20.65",
"list_currency": "USD",
"delivery_days": 2,
"delivery_date": "2026-05-15T23:00:00Z",
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_7bd0f608760c41feb939a8f3847a2998",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "FIRST_OVERNIGHT",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "163.10",
"currency": "USD",
"list_rate": "176.26",
"list_currency": "USD",
"delivery_days": 1,
"delivery_date": "2026-05-14T08:30:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 1,
"billing_type": "easypost"
},
{
"id": "rate_01627f9d38714de28e231584578add87",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "PRIORITY_OVERNIGHT",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "40.41",
"currency": "USD",
"list_rate": "135.65",
"list_currency": "USD",
"delivery_days": 1,
"delivery_date": "2026-05-14T10:30:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 1,
"billing_type": "easypost"
},
{
"id": "rate_a552d978185f4d678dc43438932678cc",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "STANDARD_OVERNIGHT",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "36.35",
"currency": "USD",
"list_rate": "122.16",
"list_currency": "USD",
"delivery_days": 1,
"delivery_date": "2026-05-14T17:00:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 1,
"billing_type": "easypost"
},
{
"id": "rate_58213215a0e747348d3f20e7d843aa4d",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "FEDEX_2_DAY_AM",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "39.58",
"currency": "USD",
"list_rate": "50.92",
"list_currency": "USD",
"delivery_days": 2,
"delivery_date": "2026-05-15T10:30:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_69dd3d4860794ef086907917c8c5b146",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "FEDEX_2_DAY",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "18.29",
"currency": "USD",
"list_rate": "42.43",
"list_currency": "USD",
"delivery_days": 2,
"delivery_date": "2026-05-15T17:00:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_b78da9583c004726a1af3432b02f0666",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "FEDEX_GROUND",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "17.29",
"currency": "USD",
"list_rate": "20.35",
"list_currency": "USD",
"delivery_days": 2,
"delivery_date": "2026-05-15T23:59:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 2,
"billing_type": "easypost"
},
{
"id": "rate_97f0a09405174d35805245e6d3e4eb9a",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "FEDEX_EXPRESS_SAVER",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "15.51",
"currency": "USD",
"list_rate": "36.77",
"list_currency": "USD",
"delivery_days": 5,
"delivery_date": "2026-05-18T17:00:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 5,
"billing_type": "easypost"
},
{
"id": "rate_58dc4d70b387444aabf0ba0a1c15cf97",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:12Z",
"updated_at": "2026-05-13T13:57:12Z",
"service": "SMART_POST",
"carrier": "FedExDefault",
"carrier_account_id": "ca_8592a7a236b5474380fa75d233cb0684",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "7.68",
"currency": "USD",
"list_rate": "16.48",
"list_currency": "USD",
"delivery_days": 3,
"delivery_date": "2026-05-18T23:59:00Z",
"delivery_date_guaranteed": true,
"est_delivery_days": 3,
"billing_type": "easypost"
}
],
"selected_rate": {
"id": "rate_fcdf7f77102e490582764cf3bbb0116d",
"object": "Rate",
"mode": "test",
"created_at": "2026-05-13T13:57:14Z",
"updated_at": "2026-05-13T13:57:14Z",
"service": "UPSGroundsaverGreaterThan1lb",
"carrier": "UPSDAP",
"carrier_account_id": "ca_4fa6d3f31ccf483484ba63153ecafc3f",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"rate": "6.88",
"currency": "USD",
"delivery_days": 4,
"delivery_date": "2026-05-17T23:00:00Z",
"est_delivery_days": 4,
"billing_type": "easypost"
},
"postage_label": {
"id": "pl_e8f81cb5c9dc4ee8858430105225383f",
"object": "PostageLabel",
"created_at": "2026-05-13T13:57:14Z",
"updated_at": "2026-05-13T13:57:14Z",
"integrated_form": "none",
"label_date": "2026-05-13T13:57:14Z",
"label_file_type": "image/png",
"label_resolution": 200,
"label_size": "4x7",
"label_type": "default",
"label_url": "https://easypost-files.s3.us-west-2.amazonaws.com/files/postage_label/20260513/e8fb33a7e017854478a9c1f26095f81b6e.png"
},
"messages": [
{
"carrier": "CanadaPost",
"type": "rate_error",
"message": "['Unable to get rates for shipments originating outside of Canada.']",
"carrier_account_id": "ca_031dbeeb1138462e8fad7c5926804945"
},
{
"carrier": "DhlEcs",
"type": "rate_error",
"message": "shipment.options.merchant_id is required",
"carrier_account_id": "ca_958eea702dfd4f69b7a3e5c464d0c0cf"
},
{
"carrier": "USAExportPBA",
"type": "rate_error",
"message": "shipment: ['shipment.from_address.country: This carrier only support shipments from US origins to international destinations.']",
"carrier_account_id": "ca_9454909f9959413a935419d7736155ce"
}
],
"options": {
"currency": "USD",
"payment": {
"type": "SENDER"
}
},
"tracking_code": "1ZXXXXXXXXXXXXXXXX",
"usps_zone": 4,
"status": "unknown",
"tracker": {
"id": "trk_138251ab21d84f9b838c3f4d0ec82fd4",
"object": "Tracker",
"mode": "test",
"created_at": "2026-05-13T13:57:14Z",
"updated_at": "2026-05-13T13:57:14Z",
"tracking_code": "1ZXXXXXXXXXXXXXXXX",
"status": "unknown",
"status_detail": "unknown",
"shipment_id": "shp_02bb9b6ce01c4fd4a708b3c514bccf0a",
"carrier": "UPSDAP",
"public_url": "https://track.easypost.com/djE6dHJrXzEzODI1MWFiMjFkODRmOWI4MzhjM2Y0ZDBlYzgyZmQ0"
},
"fees": [
{
"object": "Fee",
"type": "LabelFee",
"amount": "0.00000",
"charged": true
},
{
"object": "Fee",
"type": "PostageFee",
"amount": "6.88000",
"charged": true
},
{
"object": "Fee",
"type": "InsuranceFee",
"amount": "1.00000",
"charged": true
}
]
}

Pull Request Type

Please select the option(s) that are relevant to this PR.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement (fixing a typo, updating readme, renaming a variable name, etc.)

[Justintime50]

Nice catch! Thanks for the PR