The json string sometimes doesn't contain mediaItemsCount (optional field), thus it is necessary to provide a default value for mediaItemsCount to avoid the following error.
kotlinx.serialization.MissingFieldException: Field 'mediaItemsCount' is required, but it was missing@Serializableclass GooglePhotosAlbumListResult(val albums: List<Album>) { @Serializable class Album( val id: String, val title: String?, val coverPhotoBaseUrl: String?, val mediaItemsCount: Int? = null)}// Use non strict mode if json string have extra fields which won't be serialize into object// val json = Json.nonstrictval json = Json(JsonConfiguration.Stable.copy(strictMode = false))val jsonString = """{ "albums": [ { "mediaItemsCount": "7", "coverPhotoMediaItemId": "AOYE...", "coverPhotoBaseUrl": "https://lh3.googleusercontent.com/...", "id": "AOYE...", "productUrl": "https://photos.google.com/...", "title": "Taiwan" }, { "coverPhotoBaseUrl": "https://lh3.googleusercontent.com/...", "id": "AOYE...", "productUrl": "https://photos.google.com/...", "title": "Empty" } ]}"""val item = json.parse(GooglePhotosAlbumListResult.serializer(), jsonString)