diff --git a/server/Database.js b/server/Database.js
index 070c89d7..bd14fbd5 100644
--- a/server/Database.js
+++ b/server/Database.js
@@ -406,16 +406,6 @@ class Database {
     return Promise.all(oldBooks.map((oldBook) => this.models.book.saveFromOld(oldBook)))
   }
 
-  createPlaylistMediaItem(playlistMediaItem) {
-    if (!this.sequelize) return false
-    return this.models.playlistMediaItem.create(playlistMediaItem)
-  }
-
-  createBulkPlaylistMediaItems(playlistMediaItems) {
-    if (!this.sequelize) return false
-    return this.models.playlistMediaItem.bulkCreate(playlistMediaItems)
-  }
-
   async createLibraryItem(oldLibraryItem) {
     if (!this.sequelize) return false
     await oldLibraryItem.saveMetadata()
diff --git a/server/controllers/CollectionController.js b/server/controllers/CollectionController.js
index 23f8796f..6986f2b7 100644
--- a/server/controllers/CollectionController.js
+++ b/server/controllers/CollectionController.js
@@ -35,6 +35,9 @@ class CollectionController {
     if (!reqBody.name || !reqBody.libraryId) {
       return res.status(400).send('Invalid collection data')
     }
+    if (reqBody.description && typeof reqBody.description !== 'string') {
+      return res.status(400).send('Invalid collection description')
+    }
     const libraryItemIds = (reqBody.books || []).filter((b) => !!b && typeof b == 'string')
     if (!libraryItemIds.length) {
       return res.status(400).send('Invalid collection data. No books')
diff --git a/server/controllers/PlaylistController.js b/server/controllers/PlaylistController.js
index 5b84fe16..ee4fef5e 100644
--- a/server/controllers/PlaylistController.js
+++ b/server/controllers/PlaylistController.js
@@ -3,13 +3,16 @@ const Logger = require('../Logger')
 const SocketAuthority = require('../SocketAuthority')
 const Database = require('../Database')
 
-const Playlist = require('../objects/Playlist')
-
 /**
  * @typedef RequestUserObject
  * @property {import('../models/User')} user
  *
  * @typedef {Request & RequestUserObject} RequestWithUser
+ *
+ * @typedef RequestEntityObject
+ * @property {import('../models/Playlist')} playlist
+ *
+ * @typedef {RequestWithUser & RequestEntityObject} PlaylistControllerRequest
  */
 
 class PlaylistController {
@@ -23,48 +26,103 @@ class PlaylistController {
    * @param {Response} res
    */
   async create(req, res) {
-    const oldPlaylist = new Playlist()
-    req.body.userId = req.user.id
-    const success = oldPlaylist.setData(req.body)
-    if (!success) {
-      return res.status(400).send('Invalid playlist request data')
+    const reqBody = req.body || {}
+
+    // Validation
+    if (!reqBody.name || !reqBody.libraryId) {
+      return res.status(400).send('Invalid playlist data')
+    }
+    if (reqBody.description && typeof reqBody.description !== 'string') {
+      return res.status(400).send('Invalid playlist description')
+    }
+    const items = reqBody.items || []
+    const isPodcast = items.some((i) => i.episodeId)
+    const libraryItemIds = new Set()
+    for (const item of items) {
+      if (!item.libraryItemId || typeof item.libraryItemId !== 'string') {
+        return res.status(400).send('Invalid playlist item')
+      }
+      if (isPodcast && (!item.episodeId || typeof item.episodeId !== 'string')) {
+        return res.status(400).send('Invalid playlist item episodeId')
+      } else if (!isPodcast && item.episodeId) {
+        return res.status(400).send('Invalid playlist item episodeId')
+      }
+      libraryItemIds.add(item.libraryItemId)
     }
 
-    // Create Playlist record
-    const newPlaylist = await Database.playlistModel.createFromOld(oldPlaylist)
-
-    // Lookup all library items in playlist
-    const libraryItemIds = oldPlaylist.items.map((i) => i.libraryItemId).filter((i) => i)
-    const libraryItemsInPlaylist = await Database.libraryItemModel.findAll({
+    // Load library items
+    const libraryItems = await Database.libraryItemModel.findAll({
+      attributes: ['id', 'mediaId', 'mediaType', 'libraryId'],
       where: {
-        id: libraryItemIds
+        id: Array.from(libraryItemIds),
+        libraryId: reqBody.libraryId,
+        mediaType: isPodcast ? 'podcast' : 'book'
       }
     })
+    if (libraryItems.length !== libraryItemIds.size) {
+      return res.status(400).send('Invalid playlist data. Invalid items')
+    }
 
-    // Create playlistMediaItem records
-    const mediaItemsToAdd = []
-    let order = 1
-    for (const mediaItemObj of oldPlaylist.items) {
-      const libraryItem = libraryItemsInPlaylist.find((li) => li.id === mediaItemObj.libraryItemId)
-      if (!libraryItem) continue
-
-      mediaItemsToAdd.push({
-        mediaItemId: mediaItemObj.episodeId || libraryItem.mediaId,
-        mediaItemType: mediaItemObj.episodeId ? 'podcastEpisode' : 'book',
-        playlistId: oldPlaylist.id,
-        order: order++
+    // Validate podcast episodes
+    if (isPodcast) {
+      const podcastEpisodeIds = items.map((i) => i.episodeId)
+      const podcastEpisodes = await Database.podcastEpisodeModel.findAll({
+        attributes: ['id'],
+        where: {
+          id: podcastEpisodeIds
+        }
       })
-    }
-    if (mediaItemsToAdd.length) {
-      await Database.createBulkPlaylistMediaItems(mediaItemsToAdd)
+      if (podcastEpisodes.length !== podcastEpisodeIds.length) {
+        return res.status(400).send('Invalid playlist data. Invalid podcast episodes')
+      }
     }
 
-    const jsonExpanded = await newPlaylist.getOldJsonExpanded()
-    SocketAuthority.clientEmitter(newPlaylist.userId, 'playlist_added', jsonExpanded)
-    res.json(jsonExpanded)
+    const transaction = await Database.sequelize.transaction()
+    try {
+      // Create playlist
+      const newPlaylist = await Database.playlistModel.create(
+        {
+          libraryId: reqBody.libraryId,
+          userId: req.user.id,
+          name: reqBody.name,
+          description: reqBody.description || null
+        },
+        { transaction }
+      )
+
+      // Create playlistMediaItems
+      const playlistItemPayloads = []
+      for (const [index, item] of items.entries()) {
+        const libraryItem = libraryItems.find((li) => li.id === item.libraryItemId)
+        playlistItemPayloads.push({
+          playlistId: newPlaylist.id,
+          mediaItemId: item.episodeId || libraryItem.mediaId,
+          mediaItemType: item.episodeId ? 'podcastEpisode' : 'book',
+          order: index + 1
+        })
+      }
+
+      await Database.playlistMediaItemModel.bulkCreate(playlistItemPayloads, { transaction })
+
+      await transaction.commit()
+
+      newPlaylist.playlistMediaItems = await newPlaylist.getMediaItemsExpandedWithLibraryItem()
+
+      const jsonExpanded = newPlaylist.toOldJSONExpanded()
+      SocketAuthority.clientEmitter(newPlaylist.userId, 'playlist_added', jsonExpanded)
+      res.json(jsonExpanded)
+    } catch (error) {
+      await transaction.rollback()
+      Logger.error('[PlaylistController] create:', error)
+      res.status(500).send('Failed to create playlist')
+    }
   }
 
   /**
+   * @deprecated - Use /api/libraries/:libraryId/playlists
+   * This is not used by Abs web client or mobile apps
+   * TODO: Remove this endpoint or refactor it and make it the primary
+   *
    * GET: /api/playlists
    * Get all playlists for user
    *
@@ -72,68 +130,89 @@ class PlaylistController {
    * @param {Response} res
    */
   async findAllForUser(req, res) {
-    const playlistsForUser = await Database.playlistModel.findAll({
-      where: {
-        userId: req.user.id
-      }
-    })
-    const playlists = []
-    for (const playlist of playlistsForUser) {
-      const jsonExpanded = await playlist.getOldJsonExpanded()
-      playlists.push(jsonExpanded)
-    }
+    const playlistsForUser = await Database.playlistModel.getOldPlaylistsForUserAndLibrary(req.user.id, req.params.libraryId)
     res.json({
-      playlists
+      playlists: playlistsForUser
     })
   }
 
   /**
    * GET: /api/playlists/:id
    *
-   * @param {RequestWithUser} req
+   * @param {PlaylistControllerRequest} req
    * @param {Response} res
    */
   async findOne(req, res) {
-    const jsonExpanded = await req.playlist.getOldJsonExpanded()
-    res.json(jsonExpanded)
+    req.playlist.playlistMediaItems = await req.playlist.getMediaItemsExpandedWithLibraryItem()
+    res.json(req.playlist.toOldJSONExpanded())
   }
 
   /**
    * PATCH: /api/playlists/:id
    * Update playlist
    *
-   * @param {RequestWithUser} req
+   * Used for updating name and description or reordering items
+   *
+   * @param {PlaylistControllerRequest} req
    * @param {Response} res
    */
   async update(req, res) {
-    const updatedPlaylist = req.playlist.set(req.body)
-    let wasUpdated = false
-    const changed = updatedPlaylist.changed()
-    if (changed?.length) {
-      await req.playlist.save()
-      Logger.debug(`[PlaylistController] Updated playlist ${req.playlist.id} keys [${changed.join(',')}]`)
-      wasUpdated = true
+    // Validation
+    const reqBody = req.body || {}
+    if (reqBody.libraryId || reqBody.userId) {
+      // Could allow support for this if needed with additional validation
+      return res.status(400).send('Invalid playlist data. Cannot update libraryId or userId')
+    }
+    if (reqBody.name && typeof reqBody.name !== 'string') {
+      return res.status(400).send('Invalid playlist name')
+    }
+    if (reqBody.description && typeof reqBody.description !== 'string') {
+      return res.status(400).send('Invalid playlist description')
+    }
+    if (reqBody.items && (!Array.isArray(reqBody.items) || reqBody.items.some((i) => !i.libraryItemId || typeof i.libraryItemId !== 'string' || (i.episodeId && typeof i.episodeId !== 'string')))) {
+      return res.status(400).send('Invalid playlist items')
     }
 
-    // If array of items is passed in then update order of playlist media items
-    const libraryItemIds = req.body.items?.map((i) => i.libraryItemId).filter((i) => i) || []
-    if (libraryItemIds.length) {
+    const playlistUpdatePayload = {}
+    if (reqBody.name) playlistUpdatePayload.name = reqBody.name
+    if (reqBody.description) playlistUpdatePayload.description = reqBody.description
+
+    // Update name and description
+    let wasUpdated = false
+    if (Object.keys(playlistUpdatePayload).length) {
+      req.playlist.set(playlistUpdatePayload)
+      const changed = req.playlist.changed()
+      if (changed?.length) {
+        await req.playlist.save()
+        Logger.debug(`[PlaylistController] Updated playlist ${req.playlist.id} keys [${changed.join(',')}]`)
+        wasUpdated = true
+      }
+    }
+
+    // If array of items is set then update order of playlist media items
+    if (reqBody.items?.length) {
+      const libraryItemIds = Array.from(new Set(reqBody.items.map((i) => i.libraryItemId)))
       const libraryItems = await Database.libraryItemModel.findAll({
+        attributes: ['id', 'mediaId', 'mediaType'],
         where: {
           id: libraryItemIds
         }
       })
-      const existingPlaylistMediaItems = await updatedPlaylist.getPlaylistMediaItems({
+      if (libraryItems.length !== libraryItemIds.length) {
+        return res.status(400).send('Invalid playlist items. Items not found')
+      }
+      /** @type {import('../models/PlaylistMediaItem')[]} */
+      const existingPlaylistMediaItems = await req.playlist.getPlaylistMediaItems({
         order: [['order', 'ASC']]
       })
+      if (existingPlaylistMediaItems.length !== reqBody.items.length) {
+        return res.status(400).send('Invalid playlist items. Length mismatch')
+      }
 
       // Set an array of mediaItemId
       const newMediaItemIdOrder = []
-      for (const item of req.body.items) {
+      for (const item of reqBody.items) {
         const libraryItem = libraryItems.find((li) => li.id === item.libraryItemId)
-        if (!libraryItem) {
-          continue
-        }
         const mediaItemId = item.episodeId || libraryItem.mediaId
         newMediaItemIdOrder.push(mediaItemId)
       }
@@ -146,21 +225,21 @@ class PlaylistController {
       })
 
       // Update order on playlistMediaItem records
-      let order = 1
-      for (const playlistMediaItem of existingPlaylistMediaItems) {
-        if (playlistMediaItem.order !== order) {
+      for (const [index, playlistMediaItem] of existingPlaylistMediaItems.entries()) {
+        if (playlistMediaItem.order !== index + 1) {
           await playlistMediaItem.update({
-            order
+            order: index + 1
           })
           wasUpdated = true
         }
-        order++
       }
     }
 
-    const jsonExpanded = await updatedPlaylist.getOldJsonExpanded()
+    req.playlist.playlistMediaItems = await req.playlist.getMediaItemsExpandedWithLibraryItem()
+
+    const jsonExpanded = req.playlist.toOldJSONExpanded()
     if (wasUpdated) {
-      SocketAuthority.clientEmitter(updatedPlaylist.userId, 'playlist_updated', jsonExpanded)
+      SocketAuthority.clientEmitter(req.playlist.userId, 'playlist_updated', jsonExpanded)
     }
     res.json(jsonExpanded)
   }
@@ -169,11 +248,13 @@ class PlaylistController {
    * DELETE: /api/playlists/:id
    * Remove playlist
    *
-   * @param {RequestWithUser} req
+   * @param {PlaylistControllerRequest} req
    * @param {Response} res
    */
   async delete(req, res) {
-    const jsonExpanded = await req.playlist.getOldJsonExpanded()
+    req.playlist.playlistMediaItems = await req.playlist.getMediaItemsExpandedWithLibraryItem()
+    const jsonExpanded = req.playlist.toOldJSONExpanded()
+
     await req.playlist.destroy()
     SocketAuthority.clientEmitter(jsonExpanded.userId, 'playlist_removed', jsonExpanded)
     res.sendStatus(200)
@@ -183,12 +264,13 @@ class PlaylistController {
    * POST: /api/playlists/:id/item
    * Add item to playlist
    *
-   * @param {RequestWithUser} req
+   * This is not used by Abs web client or mobile apps. Only the batch endpoints are used.
+   *
+   * @param {PlaylistControllerRequest} req
    * @param {Response} res
    */
   async addItem(req, res) {
-    const oldPlaylist = await Database.playlistModel.getById(req.playlist.id)
-    const itemToAdd = req.body
+    const itemToAdd = req.body || {}
 
     if (!itemToAdd.libraryItemId) {
       return res.status(400).send('Request body has no libraryItemId')
@@ -198,12 +280,9 @@ class PlaylistController {
     if (!libraryItem) {
       return res.status(400).send('Library item not found')
     }
-    if (libraryItem.libraryId !== oldPlaylist.libraryId) {
+    if (libraryItem.libraryId !== req.playlist.libraryId) {
       return res.status(400).send('Library item in different library')
     }
-    if (oldPlaylist.containsItem(itemToAdd)) {
-      return res.status(400).send('Item already in playlist')
-    }
     if ((itemToAdd.episodeId && !libraryItem.isPodcast) || (libraryItem.isPodcast && !itemToAdd.episodeId)) {
       return res.status(400).send('Invalid item to add for this library type')
     }
@@ -211,15 +290,38 @@ class PlaylistController {
       return res.status(400).send('Episode not found in library item')
     }
 
-    const playlistMediaItem = {
-      playlistId: oldPlaylist.id,
-      mediaItemId: itemToAdd.episodeId || libraryItem.media.id,
-      mediaItemType: itemToAdd.episodeId ? 'podcastEpisode' : 'book',
-      order: oldPlaylist.items.length + 1
+    req.playlist.playlistMediaItems = await req.playlist.getMediaItemsExpandedWithLibraryItem()
+
+    if (req.playlist.checkHasMediaItem(itemToAdd.libraryItemId, itemToAdd.episodeId)) {
+      return res.status(400).send('Item already in playlist')
+    }
+
+    const jsonExpanded = req.playlist.toOldJSONExpanded()
+
+    const playlistMediaItem = {
+      playlistId: req.playlist.id,
+      mediaItemId: itemToAdd.episodeId || libraryItem.media.id,
+      mediaItemType: itemToAdd.episodeId ? 'podcastEpisode' : 'book',
+      order: req.playlist.playlistMediaItems.length + 1
+    }
+    await Database.playlistMediaItemModel.create(playlistMediaItem)
+
+    // Add the new item to to the old json expanded to prevent having to fully reload the playlist media items
+    if (itemToAdd.episodeId) {
+      const episode = libraryItem.media.episodes.find((ep) => ep.id === itemToAdd.episodeId)
+      jsonExpanded.items.push({
+        episodeId: itemToAdd.episodeId,
+        episode: episode.toJSONExpanded(),
+        libraryItemId: libraryItem.id,
+        libraryItem: libraryItem.toJSONMinified()
+      })
+    } else {
+      jsonExpanded.items.push({
+        libraryItemId: libraryItem.id,
+        libraryItem: libraryItem.toJSONExpanded()
+      })
     }
 
-    await Database.createPlaylistMediaItem(playlistMediaItem)
-    const jsonExpanded = await req.playlist.getOldJsonExpanded()
     SocketAuthority.clientEmitter(jsonExpanded.userId, 'playlist_updated', jsonExpanded)
     res.json(jsonExpanded)
   }
@@ -228,43 +330,36 @@ class PlaylistController {
    * DELETE: /api/playlists/:id/item/:libraryItemId/:episodeId?
    * Remove item from playlist
    *
-   * @param {RequestWithUser} req
+   * @param {PlaylistControllerRequest} req
    * @param {Response} res
    */
   async removeItem(req, res) {
-    const oldLibraryItem = await Database.libraryItemModel.getOldById(req.params.libraryItemId)
-    if (!oldLibraryItem) {
-      return res.status(404).send('Library item not found')
+    req.playlist.playlistMediaItems = await req.playlist.getMediaItemsExpandedWithLibraryItem()
+
+    let playlistMediaItem = null
+    if (req.params.episodeId) {
+      playlistMediaItem = req.playlist.playlistMediaItems.find((pmi) => pmi.mediaItemId === req.params.episodeId)
+    } else {
+      playlistMediaItem = req.playlist.playlistMediaItems.find((pmi) => pmi.mediaItem.libraryItem?.id === req.params.libraryItemId)
     }
-
-    // Get playlist media items
-    const mediaItemId = req.params.episodeId || oldLibraryItem.media.id
-    const playlistMediaItems = await req.playlist.getPlaylistMediaItems({
-      order: [['order', 'ASC']]
-    })
-
-    // Check if media item to delete is in playlist
-    const mediaItemToRemove = playlistMediaItems.find((pmi) => pmi.mediaItemId === mediaItemId)
-    if (!mediaItemToRemove) {
+    if (!playlistMediaItem) {
       return res.status(404).send('Media item not found in playlist')
     }
 
     // Remove record
-    await mediaItemToRemove.destroy()
+    await playlistMediaItem.destroy()
+    req.playlist.playlistMediaItems = req.playlist.playlistMediaItems.filter((pmi) => pmi.id !== playlistMediaItem.id)
 
     // Update playlist media items order
-    let order = 1
-    for (const mediaItem of playlistMediaItems) {
-      if (mediaItem.mediaItemId === mediaItemId) continue
-      if (mediaItem.order !== order) {
+    for (const [index, mediaItem] of req.playlist.playlistMediaItems.entries()) {
+      if (mediaItem.order !== index + 1) {
         await mediaItem.update({
-          order
+          order: index + 1
         })
       }
-      order++
     }
 
-    const jsonExpanded = await req.playlist.getOldJsonExpanded()
+    const jsonExpanded = req.playlist.toOldJSONExpanded()
 
     // Playlist is removed when there are no items
     if (!jsonExpanded.items.length) {
@@ -282,64 +377,68 @@ class PlaylistController {
    * POST: /api/playlists/:id/batch/add
    * Batch add playlist items
    *
-   * @param {RequestWithUser} req
+   * @param {PlaylistControllerRequest} req
    * @param {Response} res
    */
   async addBatch(req, res) {
-    if (!req.body.items?.length) {
-      return res.status(400).send('Invalid request body')
-    }
-    const itemsToAdd = req.body.items
-
-    const libraryItemIds = itemsToAdd.map((i) => i.libraryItemId).filter((i) => i)
-    if (!libraryItemIds.length) {
-      return res.status(400).send('Invalid request body')
+    if (!req.body.items?.length || !Array.isArray(req.body.items) || req.body.items.some((i) => !i?.libraryItemId || typeof i.libraryItemId !== 'string' || (i.episodeId && typeof i.episodeId !== 'string'))) {
+      return res.status(400).send('Invalid request body items')
     }
 
     // Find all library items
-    const libraryItems = await Database.libraryItemModel.findAll({
-      where: {
-        id: libraryItemIds
-      }
-    })
+    const libraryItemIds = new Set(req.body.items.map((i) => i.libraryItemId).filter((i) => i))
 
-    // Get all existing playlist media items
-    const existingPlaylistMediaItems = await req.playlist.getPlaylistMediaItems({
-      order: [['order', 'ASC']]
-    })
+    const oldLibraryItems = await Database.libraryItemModel.getAllOldLibraryItems({ id: Array.from(libraryItemIds) })
+    if (oldLibraryItems.length !== libraryItemIds.size) {
+      return res.status(400).send('Invalid request body items')
+    }
+
+    req.playlist.playlistMediaItems = await req.playlist.getMediaItemsExpandedWithLibraryItem()
 
     const mediaItemsToAdd = []
+    const jsonExpanded = req.playlist.toOldJSONExpanded()
 
     // Setup array of playlistMediaItem records to add
-    let order = existingPlaylistMediaItems.length + 1
-    for (const item of itemsToAdd) {
-      const libraryItem = libraryItems.find((li) => li.id === item.libraryItemId)
-      if (!libraryItem) {
-        return res.status(404).send('Item not found with id ' + item.libraryItemId)
+    let order = req.playlist.playlistMediaItems.length + 1
+    for (const item of req.body.items) {
+      const libraryItem = oldLibraryItems.find((li) => li.id === item.libraryItemId)
+
+      const mediaItemId = item.episodeId || libraryItem.media.id
+      if (req.playlist.playlistMediaItems.some((pmi) => pmi.mediaItemId === mediaItemId)) {
+        // Already exists in playlist
+        continue
       } else {
-        const mediaItemId = item.episodeId || libraryItem.mediaId
-        if (existingPlaylistMediaItems.some((pmi) => pmi.mediaItemId === mediaItemId)) {
-          // Already exists in playlist
-          continue
+        mediaItemsToAdd.push({
+          playlistId: req.playlist.id,
+          mediaItemId,
+          mediaItemType: item.episodeId ? 'podcastEpisode' : 'book',
+          order: order++
+        })
+
+        // Add the new item to to the old json expanded to prevent having to fully reload the playlist media items
+        if (item.episodeId) {
+          const episode = libraryItem.media.episodes.find((ep) => ep.id === item.episodeId)
+          jsonExpanded.items.push({
+            episodeId: item.episodeId,
+            episode: episode.toJSONExpanded(),
+            libraryItemId: libraryItem.id,
+            libraryItem: libraryItem.toJSONMinified()
+          })
         } else {
-          mediaItemsToAdd.push({
-            playlistId: req.playlist.id,
-            mediaItemId,
-            mediaItemType: item.episodeId ? 'podcastEpisode' : 'book',
-            order: order++
+          jsonExpanded.items.push({
+            libraryItemId: libraryItem.id,
+            libraryItem: libraryItem.toJSONExpanded()
           })
         }
       }
     }
 
-    let jsonExpanded = null
     if (mediaItemsToAdd.length) {
-      await Database.createBulkPlaylistMediaItems(mediaItemsToAdd)
-      jsonExpanded = await req.playlist.getOldJsonExpanded()
+      await Database.playlistMediaItemModel.bulkCreate(mediaItemsToAdd)
+
       SocketAuthority.clientEmitter(req.playlist.userId, 'playlist_updated', jsonExpanded)
-    } else {
-      jsonExpanded = await req.playlist.getOldJsonExpanded()
     }
+
     res.json(jsonExpanded)
   }
 
@@ -347,50 +446,40 @@ class PlaylistController {
    * POST: /api/playlists/:id/batch/remove
    * Batch remove playlist items
    *
-   * @param {RequestWithUser} req
+   * @param {PlaylistControllerRequest} req
    * @param {Response} res
    */
   async removeBatch(req, res) {
-    if (!req.body.items?.length) {
-      return res.status(400).send('Invalid request body')
+    if (!req.body.items?.length || !Array.isArray(req.body.items) || req.body.items.some((i) => !i?.libraryItemId || typeof i.libraryItemId !== 'string' || (i.episodeId && typeof i.episodeId !== 'string'))) {
+      return res.status(400).send('Invalid request body items')
     }
 
-    const itemsToRemove = req.body.items
-    const libraryItemIds = itemsToRemove.map((i) => i.libraryItemId).filter((i) => i)
-    if (!libraryItemIds.length) {
-      return res.status(400).send('Invalid request body')
-    }
-
-    // Find all library items
-    const libraryItems = await Database.libraryItemModel.findAll({
-      where: {
-        id: libraryItemIds
-      }
-    })
-
-    // Get all existing playlist media items for playlist
-    const existingPlaylistMediaItems = await req.playlist.getPlaylistMediaItems({
-      order: [['order', 'ASC']]
-    })
-    let numMediaItems = existingPlaylistMediaItems.length
+    req.playlist.playlistMediaItems = await req.playlist.getMediaItemsExpandedWithLibraryItem()
 
     // Remove playlist media items
     let hasUpdated = false
-    for (const item of itemsToRemove) {
-      const libraryItem = libraryItems.find((li) => li.id === item.libraryItemId)
-      if (!libraryItem) continue
-      const mediaItemId = item.episodeId || libraryItem.mediaId
-      const existingMediaItem = existingPlaylistMediaItems.find((pmi) => pmi.mediaItemId === mediaItemId)
-      if (!existingMediaItem) continue
-      await existingMediaItem.destroy()
+    for (const item of req.body.items) {
+      let playlistMediaItem = null
+      if (item.episodeId) {
+        playlistMediaItem = req.playlist.playlistMediaItems.find((pmi) => pmi.mediaItemId === item.episodeId)
+      } else {
+        playlistMediaItem = req.playlist.playlistMediaItems.find((pmi) => pmi.mediaItem.libraryItem?.id === item.libraryItemId)
+      }
+      if (!playlistMediaItem) {
+        Logger.warn(`[PlaylistController] Playlist item not found in playlist ${req.playlist.id}`, item)
+        continue
+      }
+
+      await playlistMediaItem.destroy()
+      req.playlist.playlistMediaItems = req.playlist.playlistMediaItems.filter((pmi) => pmi.id !== playlistMediaItem.id)
+
       hasUpdated = true
-      numMediaItems--
     }
 
-    const jsonExpanded = await req.playlist.getOldJsonExpanded()
+    const jsonExpanded = req.playlist.toOldJSONExpanded()
     if (hasUpdated) {
       // Playlist is removed when there are no items
-      if (!numMediaItems) {
+      if (!req.playlist.playlistMediaItems.length) {
         Logger.info(`[PlaylistController] Playlist "${req.playlist.name}" has no more items - removing it`)
         await req.playlist.destroy()
         SocketAuthority.clientEmitter(jsonExpanded.userId, 'playlist_removed', jsonExpanded)
@@ -425,33 +514,41 @@ class PlaylistController {
       return res.status(400).send('Collection has no books')
     }
 
-    const oldPlaylist = new Playlist()
-    oldPlaylist.setData({
-      userId: req.user.id,
-      libraryId: collection.libraryId,
-      name: collection.name,
-      description: collection.description || null
-    })
+    const transaction = await Database.sequelize.transaction()
+    try {
+      const playlist = await Database.playlistModel.create(
+        {
+          userId: req.user.id,
+          libraryId: collection.libraryId,
+          name: collection.name,
+          description: collection.description || null
+        },
+        { transaction }
+      )
 
-    // Create Playlist record
-    const newPlaylist = await Database.playlistModel.createFromOld(oldPlaylist)
+      const mediaItemsToAdd = []
+      for (const [index, libraryItem] of collectionExpanded.books.entries()) {
+        mediaItemsToAdd.push({
+          playlistId: playlist.id,
+          mediaItemId: libraryItem.media.id,
+          mediaItemType: 'book',
+          order: index + 1
+        })
+      }
+      await Database.playlistMediaItemModel.bulkCreate(mediaItemsToAdd, { transaction })
 
-    // Create PlaylistMediaItem records
-    const mediaItemsToAdd = []
-    let order = 1
-    for (const libraryItem of collectionExpanded.books) {
-      mediaItemsToAdd.push({
-        playlistId: newPlaylist.id,
-        mediaItemId: libraryItem.media.id,
-        mediaItemType: 'book',
-        order: order++
-      })
+      await transaction.commit()
+
+      playlist.playlistMediaItems = await playlist.getMediaItemsExpandedWithLibraryItem()
+
+      const jsonExpanded = playlist.toOldJSONExpanded()
+      SocketAuthority.clientEmitter(playlist.userId, 'playlist_added', jsonExpanded)
+      res.json(jsonExpanded)
+    } catch (error) {
+      await transaction.rollback()
+      Logger.error('[PlaylistController] createFromCollection:', error)
+      res.status(500).send('Failed to create playlist')
     }
-    await Database.createBulkPlaylistMediaItems(mediaItemsToAdd)
-
-    const jsonExpanded = await newPlaylist.getOldJsonExpanded()
-    SocketAuthority.clientEmitter(newPlaylist.userId, 'playlist_added', jsonExpanded)
-    res.json(jsonExpanded)
   }
 
   /**
diff --git a/server/models/Playlist.js b/server/models/Playlist.js
index 490e8087..7817211f 100644
--- a/server/models/Playlist.js
+++ b/server/models/Playlist.js
@@ -1,8 +1,6 @@
-const { DataTypes, Model, Op, literal } = require('sequelize')
+const { DataTypes, Model, Op } = require('sequelize')
 const Logger = require('../Logger')
 
-const oldPlaylist = require('../objects/Playlist')
-
 class Playlist extends Model {
   constructor(values, options) {
     super(values, options)
@@ -21,134 +19,23 @@ class Playlist extends Model {
     this.createdAt
     /** @type {Date} */
     this.updatedAt
-  }
 
-  static getOldPlaylist(playlistExpanded) {
-    const items = playlistExpanded.playlistMediaItems
-      .map((pmi) => {
-        const mediaItem = pmi.mediaItem || pmi.dataValues?.mediaItem
-        const libraryItemId = mediaItem?.podcast?.libraryItem?.id || mediaItem?.libraryItem?.id || null
-        if (!libraryItemId) {
-          Logger.error(`[Playlist] Invalid playlist media item - No library item id found`, JSON.stringify(pmi, null, 2))
-          return null
-        }
-        return {
-          episodeId: pmi.mediaItemType === 'podcastEpisode' ? pmi.mediaItemId : '',
-          libraryItemId
-        }
-      })
-      .filter((pmi) => pmi)
+    // Expanded properties
 
-    return new oldPlaylist({
-      id: playlistExpanded.id,
-      libraryId: playlistExpanded.libraryId,
-      userId: playlistExpanded.userId,
-      name: playlistExpanded.name,
-      description: playlistExpanded.description,
-      items,
-      lastUpdate: playlistExpanded.updatedAt.valueOf(),
-      createdAt: playlistExpanded.createdAt.valueOf()
-    })
+    /** @type {import('./PlaylistMediaItem')[]} - only set when expanded */
+    this.playlistMediaItems
   }
 
   /**
-   * Get old playlist toJSONExpanded
-   * @param {string[]} [include]
-   * @returns {Promise<oldPlaylist>} oldPlaylist.toJSONExpanded
-   */
-  async getOldJsonExpanded(include) {
-    this.playlistMediaItems =
-      (await this.getPlaylistMediaItems({
-        include: [
-          {
-            model: this.sequelize.models.book,
-            include: this.sequelize.models.libraryItem
-          },
-          {
-            model: this.sequelize.models.podcastEpisode,
-            include: {
-              model: this.sequelize.models.podcast,
-              include: this.sequelize.models.libraryItem
-            }
-          }
-        ],
-        order: [['order', 'ASC']]
-      })) || []
-
-    const oldPlaylist = this.sequelize.models.playlist.getOldPlaylist(this)
-    const libraryItemIds = oldPlaylist.items.map((i) => i.libraryItemId)
-
-    let libraryItems = await this.sequelize.models.libraryItem.getAllOldLibraryItems({
-      id: libraryItemIds
-    })
-
-    const playlistExpanded = oldPlaylist.toJSONExpanded(libraryItems)
-
-    return playlistExpanded
-  }
-
-  static createFromOld(oldPlaylist) {
-    const playlist = this.getFromOld(oldPlaylist)
-    return this.create(playlist)
-  }
-
-  static getFromOld(oldPlaylist) {
-    return {
-      id: oldPlaylist.id,
-      name: oldPlaylist.name,
-      description: oldPlaylist.description,
-      userId: oldPlaylist.userId,
-      libraryId: oldPlaylist.libraryId
-    }
-  }
-
-  static removeById(playlistId) {
-    return this.destroy({
-      where: {
-        id: playlistId
-      }
-    })
-  }
-
-  /**
-   * Get playlist by id
-   * @param {string} playlistId
-   * @returns {Promise<oldPlaylist|null>} returns null if not found
-   */
-  static async getById(playlistId) {
-    if (!playlistId) return null
-    const playlist = await this.findByPk(playlistId, {
-      include: {
-        model: this.sequelize.models.playlistMediaItem,
-        include: [
-          {
-            model: this.sequelize.models.book,
-            include: this.sequelize.models.libraryItem
-          },
-          {
-            model: this.sequelize.models.podcastEpisode,
-            include: {
-              model: this.sequelize.models.podcast,
-              include: this.sequelize.models.libraryItem
-            }
-          }
-        ]
-      },
-      order: [['playlistMediaItems', 'order', 'ASC']]
-    })
-    if (!playlist) return null
-    return this.getOldPlaylist(playlist)
-  }
-
-  /**
-   * Get old playlists for user and optionally for library
+   * Get old playlists for user and library
    *
    * @param {string} userId
-   * @param {string} [libraryId]
-   * @returns {Promise<oldPlaylist[]>}
+   * @param {string} libraryId
+   * @async
    */
-  static async getOldPlaylistsForUserAndLibrary(userId, libraryId = null) {
+  static async getOldPlaylistsForUserAndLibrary(userId, libraryId) {
     if (!userId && !libraryId) return []
+
     const whereQuery = {}
     if (userId) {
       whereQuery.userId = userId
@@ -163,7 +50,23 @@ class Playlist extends Model {
         include: [
           {
             model: this.sequelize.models.book,
-            include: this.sequelize.models.libraryItem
+            include: [
+              {
+                model: this.sequelize.models.libraryItem
+              },
+              {
+                model: this.sequelize.models.author,
+                through: {
+                  attributes: []
+                }
+              },
+              {
+                model: this.sequelize.models.series,
+                through: {
+                  attributes: ['sequence']
+                }
+              }
+            ]
           },
           {
             model: this.sequelize.models.podcastEpisode,
@@ -174,42 +77,13 @@ class Playlist extends Model {
           }
         ]
       },
-      order: [
-        [literal('name COLLATE NOCASE'), 'ASC'],
-        ['playlistMediaItems', 'order', 'ASC']
-      ]
+      order: [['playlistMediaItems', 'order', 'ASC']]
     })
 
-    const oldPlaylists = []
-    for (const playlistExpanded of playlistsExpanded) {
-      const oldPlaylist = this.getOldPlaylist(playlistExpanded)
-      const libraryItems = []
-      for (const pmi of playlistExpanded.playlistMediaItems) {
-        let mediaItem = pmi.mediaItem || pmi.dataValues.mediaItem
+    // Sort by name asc
+    playlistsExpanded.sort((a, b) => a.name.localeCompare(b.name))
 
-        if (!mediaItem) {
-          Logger.error(`[Playlist] Invalid playlist media item - No media item found`, JSON.stringify(mediaItem, null, 2))
-          continue
-        }
-        let libraryItem = mediaItem.libraryItem || mediaItem.podcast?.libraryItem
-
-        if (mediaItem.podcast) {
-          libraryItem.media = mediaItem.podcast
-          libraryItem.media.podcastEpisodes = [mediaItem]
-          delete mediaItem.podcast.libraryItem
-        } else {
-          libraryItem.media = mediaItem
-          delete mediaItem.libraryItem
-        }
-
-        const oldLibraryItem = this.sequelize.models.libraryItem.getOldLibraryItem(libraryItem)
-        libraryItems.push(oldLibraryItem)
-      }
-      const oldPlaylistJson = oldPlaylist.toJSONExpanded(libraryItems)
-      oldPlaylists.push(oldPlaylistJson)
-    }
-
-    return oldPlaylists
+    return playlistsExpanded.map((playlist) => playlist.toOldJSONExpanded())
   }
 
   /**
@@ -345,6 +219,117 @@ class Playlist extends Model {
       }
     })
   }
+
+  /**
+   * Get all media items in playlist expanded with library item
+   *
+   * @returns {Promise<import('./PlaylistMediaItem')[]>}
+   */
+  getMediaItemsExpandedWithLibraryItem() {
+    return this.getPlaylistMediaItems({
+      include: [
+        {
+          model: this.sequelize.models.book,
+          include: [
+            {
+              model: this.sequelize.models.libraryItem
+            },
+            {
+              model: this.sequelize.models.author,
+              through: {
+                attributes: []
+              }
+            },
+            {
+              model: this.sequelize.models.series,
+              through: {
+                attributes: ['sequence']
+              }
+            }
+          ]
+        },
+        {
+          model: this.sequelize.models.podcastEpisode,
+          include: [
+            {
+              model: this.sequelize.models.podcast,
+              include: this.sequelize.models.libraryItem
+            }
+          ]
+        }
+      ],
+      order: [['order', 'ASC']]
+    })
+  }
+
+  /**
+   * Get playlists toOldJSONExpanded
+   *
+   * @async
+   */
+  async getOldJsonExpanded() {
+    this.playlistMediaItems = await this.getMediaItemsExpandedWithLibraryItem()
+    return this.toOldJSONExpanded()
+  }
+
+  /**
+   * Old model used libraryItemId instead of bookId
+   *
+   * @param {string} libraryItemId
+   * @param {string} [episodeId]
+   */
+  checkHasMediaItem(libraryItemId, episodeId) {
+    if (!this.playlistMediaItems) {
+      throw new Error('playlistMediaItems are required to check Playlist')
+    }
+    if (episodeId) {
+      return this.playlistMediaItems.some((pmi) => pmi.mediaItemId === episodeId)
+    }
+    return this.playlistMediaItems.some((pmi) => pmi.mediaItem.libraryItem.id === libraryItemId)
+  }
+
+  toOldJSON() {
+    return {
+      id: this.id,
+      name: this.name,
+      libraryId: this.libraryId,
+      userId: this.userId,
+      description: this.description,
+      lastUpdate: this.updatedAt.valueOf(),
+      createdAt: this.createdAt.valueOf()
+    }
+  }
+
+  toOldJSONExpanded() {
+    if (!this.playlistMediaItems) {
+      throw new Error('playlistMediaItems are required to expand Playlist')
+    }
+
+    const json = this.toOldJSON()
+    json.items = this.playlistMediaItems.map((pmi) => {
+      if (pmi.mediaItemType === 'book') {
+        const libraryItem = pmi.mediaItem.libraryItem
+        delete pmi.mediaItem.libraryItem
+        libraryItem.media = pmi.mediaItem
+        return {
+          libraryItemId: libraryItem.id,
+          libraryItem: this.sequelize.models.libraryItem.getOldLibraryItem(libraryItem).toJSONExpanded()
+        }
+      }
+
+      const libraryItem = pmi.mediaItem.podcast.libraryItem
+      delete pmi.mediaItem.podcast.libraryItem
+      libraryItem.media = pmi.mediaItem.podcast
+      return {
+        episodeId: pmi.mediaItemId,
+        episode: pmi.mediaItem.toOldJSONExpanded(libraryItem.id),
+        libraryItemId: libraryItem.id,
+        libraryItem: this.sequelize.models.libraryItem.getOldLibraryItem(libraryItem).toJSONMinified()
+      }
+    })
+
+    return json
+  }
 }
 
 module.exports = Playlist
diff --git a/server/models/PlaylistMediaItem.js b/server/models/PlaylistMediaItem.js
index 1c53bea1..b9f76c5e 100644
--- a/server/models/PlaylistMediaItem.js
+++ b/server/models/PlaylistMediaItem.js
@@ -16,6 +16,11 @@ class PlaylistMediaItem extends Model {
     this.playlistId
     /** @type {Date} */
     this.createdAt
+
+    // Expanded properties
+
+    /** @type {import('./Book')|import('./PodcastEpisode')} - only set when expanded */
+    this.mediaItem
   }
 
   static removeByIds(playlistId, mediaItemId) {
diff --git a/server/models/PodcastEpisode.js b/server/models/PodcastEpisode.js
index 1f99361a..1fa32da7 100644
--- a/server/models/PodcastEpisode.js
+++ b/server/models/PodcastEpisode.js
@@ -170,6 +170,62 @@ class PodcastEpisode extends Model {
     })
     PodcastEpisode.belongsTo(podcast)
   }
+
+  /**
+   * AudioTrack object used in old model
+   *
+   * @returns {import('./Book').AudioFileObject|null}
+   */
+  get track() {
+    if (!this.audioFile) return null
+    const track = structuredClone(this.audioFile)
+    track.startOffset = 0
+    track.title = this.audioFile.metadata.title
+    return track
+  }
+
+  toOldJSON(libraryItemId) {
+    let enclosure = null
+    if (this.enclosureURL) {
+      enclosure = {
+        url: this.enclosureURL,
+        type: this.enclosureType,
+        length: this.enclosureSize !== null ? String(this.enclosureSize) : null
+      }
+    }
+
+    return {
+      libraryItemId: libraryItemId,
+      podcastId: this.podcastId,
+      id: this.id,
+      oldEpisodeId: this.extraData?.oldEpisodeId || null,
+      index: this.index,
+      season: this.season,
+      episode: this.episode,
+      episodeType: this.episodeType,
+      title: this.title,
+      subtitle: this.subtitle,
+      description: this.description,
+      enclosure,
+      guid: this.extraData?.guid || null,
+      pubDate: this.pubDate,
+      chapters: this.chapters?.map((ch) => ({ ...ch })) || [],
+      audioFile: this.audioFile || null,
+      publishedAt: this.publishedAt?.valueOf() || null,
+      addedAt: this.createdAt.valueOf(),
+      updatedAt: this.updatedAt.valueOf()
+    }
+  }
+
+  toOldJSONExpanded(libraryItemId) {
+    const json = this.toOldJSON(libraryItemId)
+
+    json.audioTrack = this.track
+    json.size = this.audioFile?.metadata.size || 0
+    json.duration = this.audioFile?.duration || 0
+
+    return json
+  }
 }
 
 module.exports = PodcastEpisode
diff --git a/server/objects/Playlist.js b/server/objects/Playlist.js
deleted file mode 100644
index c4b3357b..00000000
--- a/server/objects/Playlist.js
+++ /dev/null
@@ -1,148 +0,0 @@
-const uuidv4 = require("uuid").v4
-
-class Playlist {
-  constructor(playlist) {
-    this.id = null
-    this.libraryId = null
-    this.userId = null
-
-    this.name = null
-    this.description = null
-
-    this.coverPath = null
-
-    // Array of objects like { libraryItemId: "", episodeId: "" } (episodeId optional)
-    this.items = []
-
-    this.lastUpdate = null
-    this.createdAt = null
-
-    if (playlist) {
-      this.construct(playlist)
-    }
-  }
-
-  toJSON() {
-    return {
-      id: this.id,
-      libraryId: this.libraryId,
-      userId: this.userId,
-      name: this.name,
-      description: this.description,
-      coverPath: this.coverPath,
-      items: [...this.items],
-      lastUpdate: this.lastUpdate,
-      createdAt: this.createdAt
-    }
-  }
-
-  // Expands the items array
-  toJSONExpanded(libraryItems) {
-    var json = this.toJSON()
-    json.items = json.items.map(item => {
-      const libraryItem = libraryItems.find(li => li.id === item.libraryItemId)
-      if (!libraryItem) {
-        // Not found
-        return null
-      }
-      if (item.episodeId) {
-        if (!libraryItem.isPodcast) {
-          // Invalid
-          return null
-        }
-        const episode = libraryItem.media.episodes.find(ep => ep.id === item.episodeId)
-        if (!episode) {
-          // Not found
-          return null
-        }
-
-        return {
-          ...item,
-          episode: episode.toJSONExpanded(),
-          libraryItem: libraryItem.toJSONMinified()
-        }
-      } else {
-        return {
-          ...item,
-          libraryItem: libraryItem.toJSONExpanded()
-        }
-      }
-    }).filter(i => i)
-    return json
-  }
-
-  construct(playlist) {
-    this.id = playlist.id
-    this.libraryId = playlist.libraryId
-    this.userId = playlist.userId
-    this.name = playlist.name
-    this.description = playlist.description || null
-    this.coverPath = playlist.coverPath || null
-    this.items = playlist.items ? playlist.items.map(i => ({ ...i })) : []
-    this.lastUpdate = playlist.lastUpdate || null
-    this.createdAt = playlist.createdAt || null
-  }
-
-  setData(data) {
-    if (!data.userId || !data.libraryId || !data.name) {
-      return false
-    }
-    this.id = uuidv4()
-    this.userId = data.userId
-    this.libraryId = data.libraryId
-    this.name = data.name
-    this.description = data.description || null
-    this.coverPath = data.coverPath || null
-    this.items = data.items ? data.items.map(i => ({ ...i })) : []
-    this.lastUpdate = Date.now()
-    this.createdAt = Date.now()
-    return true
-  }
-
-  addItem(libraryItemId, episodeId = null) {
-    this.items.push({
-      libraryItemId,
-      episodeId: episodeId || null
-    })
-    this.lastUpdate = Date.now()
-  }
-
-  removeItem(libraryItemId, episodeId = null) {
-    if (episodeId) this.items = this.items.filter(i => i.libraryItemId !== libraryItemId || i.episodeId !== episodeId)
-    else this.items = this.items.filter(i => i.libraryItemId !== libraryItemId)
-    this.lastUpdate = Date.now()
-  }
-
-  update(payload) {
-    let hasUpdates = false
-    for (const key in payload) {
-      if (key === 'items') {
-        if (payload.items && JSON.stringify(payload.items) !== JSON.stringify(this.items)) {
-          this.items = payload.items.map(i => ({ ...i }))
-          hasUpdates = true
-        }
-      } else if (this[key] !== undefined && this[key] !== payload[key]) {
-        hasUpdates = true
-        this[key] = payload[key]
-      }
-    }
-    if (hasUpdates) {
-      this.lastUpdate = Date.now()
-    }
-    return hasUpdates
-  }
-
-  containsItem(item) {
-    if (item.episodeId) return this.items.some(i => i.libraryItemId === item.libraryItemId && i.episodeId === item.episodeId)
-    return this.items.some(i => i.libraryItemId === item.libraryItemId)
-  }
-
-  hasItemsForLibraryItem(libraryItemId) {
-    return this.items.some(i => i.libraryItemId === libraryItemId)
-  }
-
-  removeItemsForLibraryItem(libraryItemId) {
-    this.items = this.items.filter(i => i.libraryItemId !== libraryItemId)
-  }
-}
-module.exports = Playlist
\ No newline at end of file