diff --git a/app/schemas/com.pixelized.biblib.database.BibLibDatabase/1.json b/app/schemas/com.pixelized.biblib.database.BibLibDatabase/1.json
index 96a3267..8326e57 100644
--- a/app/schemas/com.pixelized.biblib.database.BibLibDatabase/1.json
+++ b/app/schemas/com.pixelized.biblib.database.BibLibDatabase/1.json
@@ -2,7 +2,7 @@
   "formatVersion": 1,
   "database": {
     "version": 1,
-    "identityHash": "30ba58aae4cd6855b019ac599eb57bdb",
+    "identityHash": "eb9a9ac9ba58cccd34d5fa89bcd4151c",
     "entities": [
       {
         "tableName": "AUTHOR",
@@ -118,12 +118,12 @@
       },
       {
         "tableName": "GENRE",
-        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`GENRE_ID` TEXT NOT NULL, `GENRE_NAME` TEXT NOT NULL, PRIMARY KEY(`GENRE_ID`))",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`GENRE_ID` INTEGER NOT NULL, `GENRE_NAME` TEXT NOT NULL, PRIMARY KEY(`GENRE_ID`))",
         "fields": [
           {
             "fieldPath": "id",
             "columnName": "GENRE_ID",
-            "affinity": "TEXT",
+            "affinity": "INTEGER",
             "notNull": true
           },
           {
@@ -245,7 +245,7 @@
       },
       {
         "tableName": "BookGenreCrossRef",
-        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`BOOK_ID` INTEGER NOT NULL, `GENRE_ID` TEXT NOT NULL, PRIMARY KEY(`BOOK_ID`, `GENRE_ID`))",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`BOOK_ID` INTEGER NOT NULL, `GENRE_ID` INTEGER NOT NULL, PRIMARY KEY(`BOOK_ID`, `GENRE_ID`))",
         "fields": [
           {
             "fieldPath": "bookId",
@@ -256,7 +256,7 @@
           {
             "fieldPath": "genreId",
             "columnName": "GENRE_ID",
-            "affinity": "TEXT",
+            "affinity": "INTEGER",
             "notNull": true
           }
         ],
@@ -284,7 +284,7 @@
     "views": [],
     "setupQueries": [
       "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
-      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '30ba58aae4cd6855b019ac599eb57bdb')"
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, 'eb9a9ac9ba58cccd34d5fa89bcd4151c')"
     ]
   }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/crossref/BookGenreCrossRef.kt b/app/src/main/java/com/pixelized/biblib/database/crossref/BookGenreCrossRef.kt
index 6db7065..7ae574b 100644
--- a/app/src/main/java/com/pixelized/biblib/database/crossref/BookGenreCrossRef.kt
+++ b/app/src/main/java/com/pixelized/biblib/database/crossref/BookGenreCrossRef.kt
@@ -10,5 +10,5 @@ data class BookGenreCrossRef(
     @ColumnInfo(name = BookDbo.ID)
     val bookId: Int,
     @ColumnInfo(name = GenreDbo.ID, index = true)
-    val genreId: String
+    val genreId: Int,
 )
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/data/GenreDbo.kt b/app/src/main/java/com/pixelized/biblib/database/data/GenreDbo.kt
index 2ec091f..42d1283 100644
--- a/app/src/main/java/com/pixelized/biblib/database/data/GenreDbo.kt
+++ b/app/src/main/java/com/pixelized/biblib/database/data/GenreDbo.kt
@@ -8,7 +8,7 @@ import androidx.room.PrimaryKey
 data class GenreDbo(
     @PrimaryKey
     @ColumnInfo(name = ID)
-    val id: String,
+    val id: Int,
     @ColumnInfo(name = NAME)
     val name: String,
 ) {
diff --git a/app/src/main/java/com/pixelized/biblib/model/book/Genre.kt b/app/src/main/java/com/pixelized/biblib/model/book/Genre.kt
index 8b9ed55..9501b79 100644
--- a/app/src/main/java/com/pixelized/biblib/model/book/Genre.kt
+++ b/app/src/main/java/com/pixelized/biblib/model/book/Genre.kt
@@ -1,6 +1,6 @@
 package com.pixelized.biblib.model.book
 
 data class Genre(
-    val id: String,
+    val id: Int,
     val name: String,
 )
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/network/client/IBibLibWebServiceAPI.kt b/app/src/main/java/com/pixelized/biblib/network/client/IBibLibWebServiceAPI.kt
index ad12895..6af7104 100644
--- a/app/src/main/java/com/pixelized/biblib/network/client/IBibLibWebServiceAPI.kt
+++ b/app/src/main/java/com/pixelized/biblib/network/client/IBibLibWebServiceAPI.kt
@@ -24,6 +24,9 @@ interface IBibLibWebServiceAPI {
     @GET("/api/series")
     suspend fun series(): SeriesListResponse
 
+    @GET("/api/tag")
+    suspend fun genre(): GenreListResponse
+
     @GET("/api/book/{id}")
     suspend fun detail(@Path("id") bookId: Int): BookDetailResponse
 
diff --git a/app/src/main/java/com/pixelized/biblib/network/data/response/GenreListResponse.kt b/app/src/main/java/com/pixelized/biblib/network/data/response/GenreListResponse.kt
new file mode 100644
index 0000000..0550902
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/network/data/response/GenreListResponse.kt
@@ -0,0 +1,49 @@
+package com.pixelized.biblib.network.data.response
+
+import com.google.gson.annotations.SerializedName
+
+data class GenreListResponse(
+    @SerializedName("lastUpdated")
+    val lastUpdated: String?,
+    @SerializedName("data")
+    val genres: List<Genres>?,
+) : ErrorResponse() {
+
+    data class Genres(
+        @SerializedName("tag_id")
+        val tag_id: Int?,
+        @SerializedName("tag_name")
+        val tag_name: String?,
+        @SerializedName("books")
+        val books: List<Books>?,
+    )
+
+    data class Books(
+        @SerializedName("book_id")
+        val book_id: Int?,
+        @SerializedName("book_title")
+        val book_title: String?,
+        @SerializedName("book_has_cover")
+        val book_has_cover: Int?,
+        @SerializedName("book_date")
+        val book_date: String?,
+        @SerializedName("book_series_index")
+        val book_series_index: Float?,
+        @SerializedName("last_modified")
+        val last_modified: String?,
+        @SerializedName("author_name")
+        val author_name: List<String>?,
+        @SerializedName("lang_id")
+        val lang_id: Int?,
+        @SerializedName("lang_code")
+        val lang_code: String?,
+        @SerializedName("rating")
+        val rating: String?,
+        @SerializedName("series_id")
+        val series_id: Int?,
+        @SerializedName("series_name")
+        val series_name: String?,
+        @SerializedName("series_sort")
+        val series_sort: String?,
+    )
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/network/factory/BookFactory.kt b/app/src/main/java/com/pixelized/biblib/network/factory/BookFactory.kt
index 0536dfc..2f7c0e7 100644
--- a/app/src/main/java/com/pixelized/biblib/network/factory/BookFactory.kt
+++ b/app/src/main/java/com/pixelized/biblib/network/factory/BookFactory.kt
@@ -3,23 +3,22 @@ package com.pixelized.biblib.network.factory
 import com.pixelized.biblib.model.book.*
 import com.pixelized.biblib.network.data.response.BookDetailResponse
 import com.pixelized.biblib.network.data.response.BookListResponse
-import com.pixelized.biblib.utils.exception.MandatoryFieldMissingException
+import com.pixelized.biblib.utils.exception.missingField
 import com.pixelized.biblib.utils.extention.toBoolean
 import java.text.SimpleDateFormat
 import java.util.*
-import kotlin.collections.HashMap
 
 class BookFactory {
-    private val parser get() = SimpleDateFormat(Factory.FORMAT, Locale.getDefault())
+    private val parser get() = SimpleDateFormat(BIBLIB_API_DATE_FORMAT, Locale.getDefault())
 
     fun fromListResponseToBook(
         response: BookListResponse.Book,
-        seriesHash: HashMap<Int, Series>,
+        seriesHash: Map<Int, Series>,
+        genreHash: Map<Int, List<Genre>>,
         isNew: Boolean = false,
         newOrder: Int? = null
     ): Book {
-        fun error(name: String) =
-            MandatoryFieldMissingException("#fromListResponseToBook()", name, response)
+        fun error(name: String) = missingField("#fromListResponseToBook()", name, response)
 
         val id: Int? = response.book_id
         val title: String? = response.book_title
@@ -80,14 +79,14 @@ class BookFactory {
             series = seriesHash[id],
             language = language,
             rating = rating,
+            genre = genreHash[id],
             isNew = isNew,
             newOrder = newOrder,
         )
     }
 
     fun fromDetailResponseToBook(response: BookDetailResponse, isNew: Boolean = false): Book {
-        fun error(name: String) =
-            MandatoryFieldMissingException("#fromDetailResponseToBook()", name, response)
+        fun error(name: String) = missingField("#fromDetailResponseToBook()", name, response)
 
         val id: Int? = response.book_id
         val title: String? = response.book_title
@@ -129,7 +128,7 @@ class BookFactory {
         } else {
             null
         }
-        val tagId: List<String>? = response.tag_id
+        val tagId: List<Int>? = response.tag_id?.mapNotNull { it.toIntOrNull() }
         val tagName: List<String>? = response.tag_name
         val tagIdSize: Int? = response.tag_id?.size
         val tagNameSize: Int? = response.tag_name?.size
diff --git a/app/src/main/java/com/pixelized/biblib/network/factory/Factory.kt b/app/src/main/java/com/pixelized/biblib/network/factory/Factory.kt
deleted file mode 100644
index 469f33f..0000000
--- a/app/src/main/java/com/pixelized/biblib/network/factory/Factory.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.pixelized.biblib.network.factory
-
-object Factory {
-    const val FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
-}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/network/factory/GenreFactory.kt b/app/src/main/java/com/pixelized/biblib/network/factory/GenreFactory.kt
new file mode 100644
index 0000000..ae50e56
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/network/factory/GenreFactory.kt
@@ -0,0 +1,30 @@
+package com.pixelized.biblib.network.factory
+
+import com.pixelized.biblib.model.book.Genre
+import com.pixelized.biblib.network.data.response.GenreListResponse
+import com.pixelized.biblib.utils.exception.missingField
+
+class GenreFactory {
+
+    fun fromListResponseToGenreHash(
+        response: GenreListResponse,
+    ): Map<Int, List<Genre>> {
+        fun error(name: String) = missingField("#fromListResponseToGenreHash()", name, response)
+
+        val hash = mutableMapOf<Int, MutableList<Genre>>()
+
+        response.genres?.forEach { data ->
+            val genre = Genre(
+                id = data.tag_id ?: throw error("id"),
+                name = data.tag_name ?: throw error("name"),
+            )
+            data.books?.forEach { book ->
+                book.book_id?.let { id ->
+                    hash.getOrPut(id) { mutableListOf() }.add(genre)
+                }
+            }
+        }
+
+        return hash
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/network/factory/SeriesFactory.kt b/app/src/main/java/com/pixelized/biblib/network/factory/SeriesFactory.kt
index ee4e044..e1dd4d5 100644
--- a/app/src/main/java/com/pixelized/biblib/network/factory/SeriesFactory.kt
+++ b/app/src/main/java/com/pixelized/biblib/network/factory/SeriesFactory.kt
@@ -2,18 +2,16 @@ package com.pixelized.biblib.network.factory
 
 import com.pixelized.biblib.model.book.Series
 import com.pixelized.biblib.network.data.response.SeriesListResponse
-import com.pixelized.biblib.utils.exception.MandatoryFieldMissingException
+import com.pixelized.biblib.utils.exception.missingField
 
 class SeriesFactory {
 
     fun fromListResponseToSeriesHash(
         response: SeriesListResponse,
-    ): HashMap<Int, Series> {
+    ): Map<Int, Series> {
+        fun error(name: String) = missingField("#fromListResponseToSeriesHash()", name, response)
 
-        fun error(name: String) =
-            MandatoryFieldMissingException("#fromListResponseToSeriesHash()", name, response)
-
-        val hash = hashMapOf<Int, Series>()
+        val hash = mutableMapOf<Int, Series>()
 
         response.series?.forEachIndexed { index, data ->
             // build the Series items
diff --git a/app/src/main/java/com/pixelized/biblib/network/factory/UserFactory.kt b/app/src/main/java/com/pixelized/biblib/network/factory/UserFactory.kt
index bcadf47..082219e 100644
--- a/app/src/main/java/com/pixelized/biblib/network/factory/UserFactory.kt
+++ b/app/src/main/java/com/pixelized/biblib/network/factory/UserFactory.kt
@@ -3,18 +3,17 @@ package com.pixelized.biblib.network.factory
 import com.pixelized.biblib.model.user.DownloadedBooks
 import com.pixelized.biblib.model.user.User
 import com.pixelized.biblib.network.data.response.UserResponse
-import com.pixelized.biblib.utils.exception.MandatoryFieldMissingException
+import com.pixelized.biblib.utils.exception.missingField
 import java.text.SimpleDateFormat
 import java.util.*
 
 class UserFactory {
-    private val parser get() = SimpleDateFormat(Factory.FORMAT, Locale.getDefault())
+    private val parser get() = SimpleDateFormat(BIBLIB_API_DATE_FORMAT, Locale.getDefault())
 
     fun fromUserResponseToUser(
         response: UserResponse
     ): User {
-        fun error(name: String) =
-            MandatoryFieldMissingException("#fromUserResponseToUser()", name, response)
+        fun error(name: String) = missingField("#fromUserResponseToUser()", name, response)
 
         val id = response.data?.id
         val created = response.data?.created?.let { parser.parse(it) }
diff --git a/app/src/main/java/com/pixelized/biblib/network/factory/_Constant.kt b/app/src/main/java/com/pixelized/biblib/network/factory/_Constant.kt
new file mode 100644
index 0000000..0396388
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/network/factory/_Constant.kt
@@ -0,0 +1,3 @@
+package com.pixelized.biblib.network.factory
+
+const val BIBLIB_API_DATE_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/repository/book/BookUtils.kt b/app/src/main/java/com/pixelized/biblib/repository/book/BookUtils.kt
index 38c6464..949c7fb 100644
--- a/app/src/main/java/com/pixelized/biblib/repository/book/BookUtils.kt
+++ b/app/src/main/java/com/pixelized/biblib/repository/book/BookUtils.kt
@@ -3,8 +3,10 @@ package com.pixelized.biblib.repository.book
 import android.util.Log
 import com.pixelized.biblib.network.client.IBibLibClient
 import com.pixelized.biblib.network.data.response.BookListResponse
+import com.pixelized.biblib.network.data.response.GenreListResponse
 import com.pixelized.biblib.network.data.response.SeriesListResponse
 import com.pixelized.biblib.network.factory.BookFactory
+import com.pixelized.biblib.network.factory.GenreFactory
 import com.pixelized.biblib.network.factory.SeriesFactory
 import com.pixelized.biblib.repository.apiCache.IAPICacheRepository
 import com.pixelized.biblib.utils.exception.BookFetchException
@@ -63,9 +65,11 @@ suspend fun loadAllBooks(
     repository: IBookRepository,
     bookFactory: BookFactory = BookFactory(),
     seriesFactory: SeriesFactory = SeriesFactory(),
+    genresFactory: GenreFactory = GenreFactory(),
 ): Boolean {
     val seriesResponse: SeriesListResponse = client.service.series()
     val bookResponse: BookListResponse = client.service.list()
+    val genreResponse: GenreListResponse = client.service.genre()
 
     return when {
         bookResponse.isError -> {
@@ -76,11 +80,17 @@ suspend fun loadAllBooks(
             Log.e("loadAllBooks", seriesResponse.message ?: "")
             throw BookFetchException(seriesResponse.message)
         }
+        genreResponse.isError -> {
+            Log.e("loadAllBooks", genreResponse.message ?: "")
+            throw BookFetchException(genreResponse.message)
+        }
         else -> {
             // prepare a list of new book ids.
             val newIds = cache.new?.data?.map { it.book_id } ?: listOf()
             // prepare a hash of series by books ids.
-            val series = seriesFactory.fromListResponseToSeriesHash(seriesResponse)
+            val series = seriesFactory.fromListResponseToSeriesHash(response = seriesResponse)
+            // prepare a hash of genre by books ids.
+            val genres = genresFactory.fromListResponseToGenreHash(response = genreResponse)
             // parse books.
             val books = bookResponse.data?.map { dto ->
                 val isNew = newIds.contains(dto.book_id)
@@ -88,6 +98,7 @@ suspend fun loadAllBooks(
                 return@map bookFactory.fromListResponseToBook(
                     response = dto,
                     seriesHash = series,
+                    genreHash = genres,
                     isNew = isNew,
                     newOrder = index
                 )
diff --git a/app/src/main/java/com/pixelized/biblib/utils/exception/MandatoryFieldMissingException.kt b/app/src/main/java/com/pixelized/biblib/utils/exception/MandatoryFieldMissingException.kt
index f32f61d..c4f6322 100644
--- a/app/src/main/java/com/pixelized/biblib/utils/exception/MandatoryFieldMissingException.kt
+++ b/app/src/main/java/com/pixelized/biblib/utils/exception/MandatoryFieldMissingException.kt
@@ -1,4 +1,7 @@
 package com.pixelized.biblib.utils.exception
 
-class MandatoryFieldMissingException(method: String, name: String, json: Any) :
+private class MandatoryFieldMissingException(method: String, name: String, json: Any) :
+    RuntimeException("Parse exception: Mandatory field:'$name' is missing from:'$method', with data:$json")
+
+fun missingField(method: String, name: String, json: Any) =
     RuntimeException("Parse exception: Mandatory field:'$name' is missing from:'$method', with data:$json")
\ No newline at end of file