curl --request GET \
  --url https://api.hubapi.com/crm-objects/v1/objects/line_items/{id}

"\nExample GET URL:\nhttps://api.hubapi.com/crm-objects/v1/objects/line_items/9845651?properties=hs_product_id\n\nExample response:\n{\n  \"objectType\": \"LINE_ITEM\",\n  \"portalId\": 62515,\n  \"objectId\": 9845651,\n  \"properties\": {\n    \"hs_product_id\": {\n      \"versions\": [\n        {\n          \"name\": \"hs_product_id\",\n          \"value\": \"1645342\",\n          \"sourceVid\": []\n        }\n      ],\n      \"value\": \"1645342\",\n      \"timestamp\": 0,\n      \"source\": null,\n      \"sourceId\": null\n    }\n  },\n  \"version\": 1,\n  \"isDeleted\": false\n}\n\nExample GET with properties:\nhttps://api.hubapi.com/crm-objects/v1/objects/line_items/9845651?properties=quantity&properties=price&properties=name&properties=hs_product_id\n\nExample response:\n{\n  \"objectType\": \"LINE_ITEM\",\n  \"portalId\": 62515,\n  \"objectId\": 9845651,\n  \"properties\": {\n    \"quantity\": {\n      \"versions\": [\n        {\n          \"name\": \"quantity\",\n          \"value\": \"25\",\n          \"timestamp\": 1525369755209,\n          \"source\": \"API\",\n          \"sourceVid\": []\n        }\n      ],\n      \"value\": \"25\",\n      \"timestamp\": 1525369755209,\n      \"source\": \"API\",\n      \"sourceId\": null\n    },\n    \"price\": {\n      \"versions\": [\n        {\n          \"name\": \"price\",\n          \"value\": \"27.50\",\n          \"timestamp\": 1525299376761,\n          \"source\": \"API\",\n          \"sourceVid\": []\n        }\n      ],\n      \"value\": \"27.50\",\n      \"timestamp\": 1525299376761,\n      \"source\": \"API\",\n      \"sourceId\": null\n    },\n    \"name\": {\n      \"versions\": [\n        {\n          \"name\": \"name\",\n          \"value\": \"A custom name for the product for this line item.\",\n          \"timestamp\": 1525369755209,\n          \"source\": \"API\",\n          \"sourceVid\": []\n        }\n      ],\n      \"value\": \"A custom name for the product for this line item.\",\n      \"timestamp\": 1525369755209,\n      \"source\": \"API\",\n      \"sourceId\": null\n    },\n    \"hs_product_id\": {\n      \"versions\": [\n        {\n          \"name\": \"hs_product_id\",\n          \"value\": \"1645342\",\n          \"sourceVid\": []\n        }\n      ],\n      \"value\": \"1645342\",\n      \"timestamp\": 0,\n      \"source\": null,\n      \"sourceId\": null\n    }\n  },\n  \"version\": 1,\n  \"isDeleted\": false\n}"