@Harpreet Sangar Sorry for the late reply! Here's the full schema. I ended up removing the reference for now since I couldn't get it working, and I added

tag_names

in the meantime.

tag_ids

is the field I tried to add the reference to (I commented it out in the schema)

let contactsSchema: CollectionCreateSchema = {
    name: collectionName,
    enable_nested_fields: true,
    fields: [
      { name: 'account_id', type: 'string', optional: true, sort: false },
      { name: 'authorized_account_ids', type: 'string[]', optional: true, sort: false },
      { name: 'added_at', type: 'int64', optional: true, sort: true },
      {
        name: 'contact_card.associated_card_id',
        type: 'string',
        optional: true,
        sort: false,
      },
      {
        name: 'contact_card.associated_card_name',
        type: 'string',
        optional: true,
        sort: true,
      },
      { name: 'contact_card.company', type: 'string', optional: true, sort: true },
      {
        name: 'contact_card.contact_card_id',
        type: 'string',
        optional: true,
        sort: false,
      },
      {
        name: 'contact_card.contact_id',
        type: 'string',
        optional: true,
        sort: false,
      },
      {
        name: 'contact_card.family_name',
        type: 'string',
        optional: true,
        sort: true,
      },
      {
        name: 'contact_card.given_name',
        type: 'string',
        optional: true,
        sort: true,
      },
      { name: 'contact_card.is_live_contact', type: 'bool', optional: true, sort: false },
      { name: 'contact_card.source', type: 'int32', optional: true, sort: false },
      { name: 'contact_card.tag_ids', type: 'string[]', optional: true, sort: false // reference: 'tags.id' },
      { name: 'contact_card.tag_names', type: 'string[]', optional: true, sort: false },
      { name: 'contact_card.title', type: 'string', optional: true, sort: true },
    ],
    token_separators: ['+', '-', '@', '.'],
  };