diff --git a/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.html b/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.html
index 8a83dab..4b0ccf2 100644
--- a/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.html
+++ b/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.html
@@ -1,6 +1,6 @@
-@for (category of categories$ | async; track category) {
+@for (category of categories(); track category.id) {
   <div class="category {{category.isOpenned ? 'openned' : ''}}">
-    <div id="category-{{category.id}}" class="category-header" (click)="setOpenned(category)">
+    <div id="category-{{category.id}}" class="category-header" (click)="setOpened(category)">
       {{ category.name }}
       <mat-icon>chevron_right</mat-icon>
     </div>
diff --git a/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.ts b/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.ts
index 226a9c2..87d2ff4 100644
--- a/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.ts
+++ b/frontend/src/app/components/side-menu/categories-menu/categories-menu.component.ts
@@ -1,8 +1,7 @@
 import {CommonModule} from "@angular/common";
-import {Component, EventEmitter, inject, OnInit, Output} from "@angular/core";
+import {Component, inject, OnInit, output, Signal} from "@angular/core";
 import {MatIconModule} from "@angular/material/icon";
 import {DisplayableCategory, SideMenuService} from "../side-menu.service";
-import {Observable} from "rxjs";
 import {RouterModule} from "@angular/router";
 
 @Component({
@@ -16,45 +15,44 @@ import {RouterModule} from "@angular/router";
   styleUrl: './categories-menu.component.scss'
 })
 export class CategoriesMenuComponent implements OnInit {
-  private sideMenuService = inject(SideMenuService);
-  @Output()
-  categoryClicked = new EventEmitter<void>();
+  readonly #sideMenuService = inject(SideMenuService);
+  categoryClicked = output<void>();
 
   ngOnInit(): void {
-    this.sideMenuService.loadCategories();
+    this.#sideMenuService.loadCategories();
   }
 
-  get categories$(): Observable<DisplayableCategory[]> {
-    return this.sideMenuService.categories$;
+  get categories(): Signal<DisplayableCategory[]> {
+    return this.#sideMenuService.categories;
   }
 
-  setOpenned(category: DisplayableCategory): void {
+  setOpened(category: DisplayableCategory): void {
     if (category.isOpenned) {
       const categoryDiv = document.getElementById(`category-${category.id}`);
       if (categoryDiv) {
-        this.closeAccordion(categoryDiv);
+        this.#closeAccordion(categoryDiv);
       }
     } else {
       const categoriesDivs = document.getElementsByClassName('category-header');
       Array.from(categoriesDivs)
         .map(category => category as HTMLElement)
-        .forEach(categoryDiv => this.closeAccordion(categoryDiv));
+        .forEach(categoryDiv => this.#closeAccordion(categoryDiv));
 
       const categoryDiv = document.getElementById(`category-${category.id}`);
       if (categoryDiv) {
-        this.openAccordion(categoryDiv);
+        this.#openAccordion(categoryDiv);
       }
     }
 
-    this.sideMenuService.setOpenned(category);
+    this.#sideMenuService.setOpened(category);
   }
 
-  private closeAccordion(categoryDiv: HTMLElement): void {
+  #closeAccordion(categoryDiv: HTMLElement): void {
     const divContent = categoryDiv?.nextElementSibling as HTMLElement;
     divContent.style.maxHeight = '0';
   }
 
-  private openAccordion(categoryDiv: HTMLElement): void {
+  #openAccordion(categoryDiv: HTMLElement): void {
     const divContent = categoryDiv?.nextElementSibling as HTMLElement;
     divContent.style.maxHeight = `${divContent.scrollHeight}px`;
   }
diff --git a/frontend/src/app/components/side-menu/side-menu.component.html b/frontend/src/app/components/side-menu/side-menu.component.html
index 583647e..82a67e6 100644
--- a/frontend/src/app/components/side-menu/side-menu.component.html
+++ b/frontend/src/app/components/side-menu/side-menu.component.html
@@ -14,6 +14,6 @@
     </button>
   </h1>
   <h2 i18n>Categories</h2>
-  <app-categories-menu (categoryClicked)="close()"></app-categories-menu>
+  <app-categories-menu (categoryClicked)="close()"/>
 </div>
 <div class="overlay {{ isOpened() ? 'displayed' : ''}}" (click)="close()"></div>
diff --git a/frontend/src/app/components/side-menu/side-menu.service.ts b/frontend/src/app/components/side-menu/side-menu.service.ts
index c878ea1..b594410 100644
--- a/frontend/src/app/components/side-menu/side-menu.service.ts
+++ b/frontend/src/app/components/side-menu/side-menu.service.ts
@@ -1,6 +1,5 @@
-import {inject, Injectable} from '@angular/core';
+import {inject, Injectable, Signal, signal} from '@angular/core';
 import {MatSnackBar} from '@angular/material/snack-bar';
-import {BehaviorSubject, Observable} from 'rxjs';
 import {CategoryRestService} from '../../core/rest-services/category/category.rest-service';
 import {Category} from '../../core/rest-services/category/model/category';
 
@@ -20,68 +19,60 @@ export interface DisplayableSubCategory {
   providedIn: 'root'
 })
 export class SideMenuService {
-  private categoryRestService = inject(CategoryRestService);
-  private snackBar = inject(MatSnackBar);
-  private categoriesSubject = new BehaviorSubject<DisplayableCategory[]>([]);
-  private isLoadingSubject = new BehaviorSubject<boolean>(false);
-  private isLoadedSubject = new BehaviorSubject<boolean>(false);
+  readonly #categoryRestService = inject(CategoryRestService);
+  readonly #snackBar = inject(MatSnackBar);
+  #categories = signal<DisplayableCategory[]>([]);
+  #isLoading = signal(false);
+  isLoaded = signal(false);
 
-  private mapToDisplayableCategory(category: Category): DisplayableCategory {
+  #mapToDisplayableCategory(category: Category): DisplayableCategory {
     return {
       id: category.id,
       name: category.name,
-      subCategories: category.subCategories.map(subCategory => this.mapToDisplayableSubCategory(subCategory)),
+      subCategories: category.subCategories.map(subCategory => this.#mapToDisplayableSubCategory(subCategory)),
       isOpenned: false
     };
   }
 
-  private mapToDisplayableSubCategory(subCategory: Category): DisplayableSubCategory {
+  #mapToDisplayableSubCategory(subCategory: Category): DisplayableSubCategory {
     return {
       id: subCategory.id,
       name: subCategory.name
     }
   }
 
-  private get categories(): DisplayableCategory[] {
-    return this.categoriesSubject.value;
+  get categories(): Signal<DisplayableCategory[]> {
+    return this.#categories.asReadonly();
   }
 
-  private save(categories: DisplayableCategory[]): void {
-    this.categoriesSubject.next(categories);
-  }
-
-  get categories$(): Observable<DisplayableCategory[]> {
-    return this.categoriesSubject.asObservable();
-  }
-
-  get isLoading$(): Observable<boolean> {
-    return this.isLoadingSubject.asObservable();
+  get isLoading(): Signal<boolean> {
+    return this.#isLoading.asReadonly();
   }
 
   loadCategories(): void {
-    this.isLoadingSubject.next(true);
-    this.isLoadedSubject.next(false);
+    this.#isLoading.set(true);
+    this.isLoaded.set(false);
 
-    this.categoryRestService.getCategories()
+    this.#categoryRestService.getCategories()
       .then(categories => {
         const displayableCategories = categories
           .filter(category => category.subCategories?.length)
-          .map(category => this.mapToDisplayableCategory(category));
-        this.categoriesSubject.next(displayableCategories);
+          .map(category => this.#mapToDisplayableCategory(category));
+        this.#categories.set(displayableCategories);
       })
       .catch(error => {
         const errorMessage = $localize`An error occured while loading categories.`;
         console.error(errorMessage, error);
-        this.snackBar.open(errorMessage, $localize`Close`, {duration: 5000});
+        this.#snackBar.open(errorMessage, $localize`Close`, {duration: 5000});
       })
       .finally(() => {
-        this.isLoadingSubject.next(false);
-        this.isLoadedSubject.next(true);
+        this.#isLoading.set(false);
+        this.isLoaded.set(true);
       });
   }
 
-  setOpenned(category: DisplayableCategory): void {
-    const categories = this.categories;
+  setOpened(category: DisplayableCategory): void {
+    const categories = this.#categories();
     const matchingCategory = categories.find(categoryTemp => categoryTemp.id === category.id);
     if (matchingCategory) {
       const actualOpennedCategory = categories.find(category => category.isOpenned);
@@ -91,7 +82,7 @@ export class SideMenuService {
         categories.forEach(categoryTemp => categoryTemp.isOpenned = false);
         matchingCategory.isOpenned = true;
       }
-      this.save(categories);
+      this.#categories.set(categories);
     }
   }
 }