diff --git a/src/lib/indexedDB/filesystem.ts b/src/lib/indexedDB/filesystem.ts
index 5c9fc4d..293c16d 100644
--- a/src/lib/indexedDB/filesystem.ts
+++ b/src/lib/indexedDB/filesystem.ts
@@ -15,16 +15,28 @@ interface FileInfo {
   contentType: string;
   createdAt?: Date;
   lastModifiedAt: Date;
+  categoryIds: number[];
+}
+
+export type CategoryId = "root" | number;
+
+interface CategoryInfo {
+  id: number;
+  parentId: CategoryId;
+  name: string;
+  files: { id: number; isRecursive: boolean }[];
 }
 
 const filesystem = new Dexie("filesystem") as Dexie & {
   directory: EntityTable<DirectoryInfo, "id">;
   file: EntityTable<FileInfo, "id">;
+  category: EntityTable<CategoryInfo, "id">;
 };
 
-filesystem.version(1).stores({
+filesystem.version(2).stores({
   directory: "id, parentId",
   file: "id, parentId",
+  category: "id, parentId",
 });
 
 export const getDirectoryInfos = async (parentId: DirectoryId) => {
@@ -59,13 +71,29 @@ export const deleteFileInfo = async (id: number) => {
   await filesystem.file.delete(id);
 };
 
+export const getCategoryInfos = async (parentId: CategoryId) => {
+  return await filesystem.category.where({ parentId }).toArray();
+};
+
+export const getCategoryInfo = async (id: number) => {
+  return await filesystem.category.get(id);
+};
+
+export const storeCategoryInfo = async (categoryInfo: CategoryInfo) => {
+  await filesystem.category.put(categoryInfo);
+};
+
+export const deleteCategoryInfo = async (id: number) => {
+  await filesystem.category.delete(id);
+};
+
 export const cleanupDanglingInfos = async () => {
   const validDirectoryIds: number[] = [];
   const validFileIds: number[] = [];
-  const queue: DirectoryId[] = ["root"];
+  const directoryQueue: DirectoryId[] = ["root"];
 
   while (true) {
-    const directoryId = queue.shift();
+    const directoryId = directoryQueue.shift();
     if (!directoryId) break;
 
     const [subDirectories, files] = await Promise.all([
@@ -74,13 +102,28 @@ export const cleanupDanglingInfos = async () => {
     ]);
     subDirectories.forEach(({ id }) => {
       validDirectoryIds.push(id);
-      queue.push(id);
+      directoryQueue.push(id);
     });
     files.forEach(({ id }) => validFileIds.push(id));
   }
 
+  const validCategoryIds: number[] = [];
+  const categoryQueue: CategoryId[] = ["root"];
+
+  while (true) {
+    const categoryId = categoryQueue.shift();
+    if (!categoryId) break;
+
+    const subCategories = await filesystem.category.where({ parentId: categoryId }).toArray();
+    subCategories.forEach(({ id }) => {
+      validCategoryIds.push(id);
+      categoryQueue.push(id);
+    });
+  }
+
   await Promise.all([
     filesystem.directory.where("id").noneOf(validDirectoryIds).delete(),
     filesystem.file.where("id").noneOf(validFileIds).delete(),
+    filesystem.category.where("id").noneOf(validCategoryIds).delete(),
   ]);
 };
diff --git a/src/lib/modules/filesystem.ts b/src/lib/modules/filesystem.ts
index 0e786ce..dc1208e 100644
--- a/src/lib/modules/filesystem.ts
+++ b/src/lib/modules/filesystem.ts
@@ -9,7 +9,12 @@ import {
   getFileInfo as getFileInfoFromIndexedDB,
   storeFileInfo,
   deleteFileInfo,
+  getCategoryInfos as getCategoryInfosFromIndexedDB,
+  getCategoryInfo as getCategoryInfoFromIndexedDB,
+  storeCategoryInfo,
+  deleteCategoryInfo,
   type DirectoryId,
+  type CategoryId,
 } from "$lib/indexedDB";
 import { unwrapDataKey, decryptString } from "$lib/modules/crypto";
 import type {
@@ -49,8 +54,6 @@ export interface FileInfo {
   categoryIds: number[];
 }
 
-type CategoryId = "root" | number;
-
 export type CategoryInfo =
   | {
       id: "root";
@@ -161,7 +164,7 @@ const fetchFileInfoFromIndexedDB = async (id: number, info: Writable<FileInfo |
   const file = await getFileInfoFromIndexedDB(id);
   if (!file) return;
 
-  info.set({ ...file, categoryIds: [] });
+  info.set(file);
 };
 
 const decryptDate = async (ciphertext: string, iv: string, dataKey: CryptoKey) => {
@@ -214,6 +217,7 @@ const fetchFileInfoFromServer = async (
     contentType: metadata.contentType,
     createdAt,
     lastModifiedAt,
+    categoryIds: metadata.categories,
   });
 };
 
@@ -235,6 +239,26 @@ export const getFileInfo = (fileId: number, masterKey: CryptoKey) => {
   return info;
 };
 
+const fetchCategoryInfoFromIndexedDB = async (
+  id: CategoryId,
+  info: Writable<CategoryInfo | null>,
+) => {
+  if (get(info)) return;
+
+  const [category, subCategories] = await Promise.all([
+    id !== "root" ? getCategoryInfoFromIndexedDB(id) : undefined,
+    getCategoryInfosFromIndexedDB(id),
+  ]);
+  const subCategoryIds = subCategories.map(({ id }) => id);
+
+  if (id === "root") {
+    info.set({ id, subCategoryIds });
+  } else {
+    if (!category) return;
+    info.set({ id, name: category.name, subCategoryIds, files: category.files });
+  }
+};
+
 const fetchCategoryInfoFromServer = async (
   id: CategoryId,
   info: Writable<CategoryInfo | null>,
@@ -243,6 +267,7 @@ const fetchCategoryInfoFromServer = async (
   let res = await callGetApi(`/api/category/${id}`);
   if (res.status === 404) {
     info.set(null);
+    await deleteCategoryInfo(id as number);
     return;
   } else if (!res.ok) {
     throw new Error("Failed to fetch category information");
@@ -262,6 +287,7 @@ const fetchCategoryInfoFromServer = async (
     }
 
     const { files }: CategoryFileListResponse = await res.json();
+    const filesMapped = files.map(({ file, isRecursive }) => ({ id: file, isRecursive }));
 
     info.set({
       id,
@@ -269,7 +295,13 @@ const fetchCategoryInfoFromServer = async (
       dataKeyVersion: new Date(metadata!.dekVersion),
       name,
       subCategoryIds: subCategories,
-      files: files.map(({ file, isRecursive }) => ({ id: file, isRecursive })),
+      files: filesMapped,
+    });
+    await storeCategoryInfo({
+      id,
+      parentId: metadata!.parent,
+      name,
+      files: filesMapped,
     });
   }
 };
@@ -279,6 +311,7 @@ const fetchCategoryInfo = async (
   info: Writable<CategoryInfo | null>,
   masterKey: CryptoKey,
 ) => {
+  await fetchCategoryInfoFromIndexedDB(id, info);
   await fetchCategoryInfoFromServer(id, info, masterKey);
 };