firestore.indexes.json

{
  "indexes": [
    {
      "collectionGroup": "courses",
      "queryScope": "COLLECTION",
      "fields": [
        {
          "fieldPath": "categories",
          "arrayConfig": "CONTAINS"
        },
        {
          "fieldPath": "seqNo",
          "order": "ASCENDING"
        }
      ]
    },
    {
      "collectionGroup": "courses",
      "queryScope": "COLLECTION",
      "fields": [
        {
          "fieldPath": "url",
          "order": "ASCENDING"
        },
        {
          "fieldPath": "seqNo",
          "order": "ASCENDING"
        }
      ]
    }
  ],
  "fieldOverrides": [
    {
      "collectionGroup": "lessons",
      "fieldPath": "seqNo",
      "indexes": [
        {
          "order": "ASCENDING",
          "queryScope": "COLLECTION"
        },
        {
          "order": "DESCENDING",
          "queryScope": "COLLECTION"
        },
        {
          "arrayConfig": "CONTAINS",
          "queryScope": "COLLECTION"
        },
        {
          "order": "ASCENDING",
          "queryScope": "COLLECTION_GROUP"
        }
      ]
    }
  ]
}