diff --git a/src/app/features/project-editor/components/project-editor-nav.component.ts b/src/app/features/project-editor/components/project-editor-nav.component.ts
index 5c0c741..0d5e361 100644
--- a/src/app/features/project-editor/components/project-editor-nav.component.ts
+++ b/src/app/features/project-editor/components/project-editor-nav.component.ts
@@ -23,6 +23,7 @@ export class ProjectEditorNavComponent {
     { id: 'widgets', label: 'builder.widgets' },
     { id: 'static-pages', label: 'builder.staticPages' },
     { id: 'features', label: 'builder.marketplaceFeatures' },
+    { id: 'languages', label: 'builder.languagesTab' },
     { id: 'preview', label: 'builder.preview' },
   ];
 }
diff --git a/src/app/features/project-editor/facade/project-editor.facade.ts b/src/app/features/project-editor/facade/project-editor.facade.ts
index d1fac23..da51d84 100644
--- a/src/app/features/project-editor/facade/project-editor.facade.ts
+++ b/src/app/features/project-editor/facade/project-editor.facade.ts
@@ -4,6 +4,7 @@ import { BootstrapConfig, DEFAULT_CATALOG_CONFIG, DEFAULT_HEADER_CONFIG, DEFAULT
 import { ConfigService } from '../../../core/config/config.service';
 import { ProjectEditorIoService } from '../services/project-editor-io.service';
 import { ProjectEditorPreviewService } from '../services/project-editor-preview.service';
+import { LocaleSyncService } from '../services/locale-sync.service';
 import { ProjectEditorState } from '../models/project-editor.model';
 
 @Injectable({ providedIn: 'root' })
@@ -11,6 +12,7 @@ export class ProjectEditorFacade {
   private readonly configService = inject(ConfigService);
   private readonly ioService = inject(ProjectEditorIoService);
   private readonly previewService = inject(ProjectEditorPreviewService);
+  private readonly localeSync = inject(LocaleSyncService);
 
   private readonly state = signal<ProjectEditorState>({
     bootstrap: null,
@@ -70,6 +72,22 @@ export class ProjectEditorFacade {
     this.state.update(current => ({ ...current, activeSection }));
   }
 
+  addLocale(locale: string): void {
+    this.updateBootstrap(current => this.localeSync.addLocale(current, locale));
+  }
+
+  removeLocale(locale: string): void {
+    this.updateBootstrap(current => this.localeSync.removeLocale(current, locale));
+  }
+
+  setDefaultLocale(locale: string): void {
+    this.updateBootstrap(current => ({
+      ...current,
+      tenant: { ...current.tenant, defaultLocale: locale },
+      localization: { ...current.localization, defaultLocale: locale },
+    }));
+  }
+
   private normalize(config: BootstrapConfig): BootstrapConfig {
     return {
       ...config,
diff --git a/src/app/features/project-editor/models/project-editor.model.ts b/src/app/features/project-editor/models/project-editor.model.ts
index 73f7e9e..9b7956e 100644
--- a/src/app/features/project-editor/models/project-editor.model.ts
+++ b/src/app/features/project-editor/models/project-editor.model.ts
@@ -10,6 +10,7 @@ export type ProjectEditorSectionId =
   | 'widgets'
   | 'static-pages'
   | 'features'
+  | 'languages'
   | 'preview';
 
 export interface ProjectEditorState {
diff --git a/src/app/features/project-editor/pages/project-editor-page.component.html b/src/app/features/project-editor/pages/project-editor-page.component.html
index 9a6b85d..59d5cd2 100644
--- a/src/app/features/project-editor/pages/project-editor-page.component.html
+++ b/src/app/features/project-editor/pages/project-editor-page.component.html
@@ -23,6 +23,7 @@
         @case ('widgets') { <app-project-editor-widgets-section /> }
         @case ('static-pages') { <app-static-pages-editor /> }
         @case ('features') { <app-project-editor-features-section /> }
+        @case ('languages') { <app-project-editor-languages-section /> }
         @case ('preview') { <app-project-editor-preview-section /> }
       }
     </section>
diff --git a/src/app/features/project-editor/pages/project-editor-page.component.ts b/src/app/features/project-editor/pages/project-editor-page.component.ts
index 87d5dee..3773013 100644
--- a/src/app/features/project-editor/pages/project-editor-page.component.ts
+++ b/src/app/features/project-editor/pages/project-editor-page.component.ts
@@ -12,13 +12,14 @@ import { ProjectEditorFooterSectionComponent } from '../sections/footer-section.
 import { ProjectEditorHomepageSectionComponent } from '../sections/homepage-section.component';
 import { ProjectEditorWidgetsSectionComponent } from '../sections/widgets-section.component';
 import { ProjectEditorFeaturesSectionComponent } from '../sections/features-section.component';
+import { ProjectEditorLanguagesSectionComponent } from '../sections/languages-section.component';
 import { ProjectEditorPreviewSectionComponent } from '../sections/preview-section.component';
 import { TranslatePipe } from '../../../i18n/translate.pipe';
 import { StaticPagesEditorComponent } from '../../content-management/components/static-pages-editor.component';
 import { ProjectEditorSectionId } from '../models/project-editor.model';
 
 const KNOWN_SECTIONS: ProjectEditorSectionId[] = [
-  'general', 'branding', 'theme', 'header', 'footer', 'homepage', 'widgets', 'static-pages', 'features', 'preview'
+  'general', 'branding', 'theme', 'header', 'footer', 'homepage', 'widgets', 'static-pages', 'features', 'languages', 'preview'
 ];
 
 @Component({
@@ -36,6 +37,7 @@ const KNOWN_SECTIONS: ProjectEditorSectionId[] = [
     ProjectEditorWidgetsSectionComponent,
     StaticPagesEditorComponent,
     ProjectEditorFeaturesSectionComponent,
+    ProjectEditorLanguagesSectionComponent,
     ProjectEditorPreviewSectionComponent,
   ],
   templateUrl: './project-editor-page.component.html',
diff --git a/src/app/features/project-editor/sections/languages-section.component.html b/src/app/features/project-editor/sections/languages-section.component.html
new file mode 100644
index 0000000..a31b5a0
--- /dev/null
+++ b/src/app/features/project-editor/sections/languages-section.component.html
@@ -0,0 +1,33 @@
+<section class="editor-section-card">
+  <div class="editor-actions">
+    <h2>{{ 'builder.languagesTab' | translate }}</h2>
+  </div>
+
+  <div class="editor-actions">
+    <input
+      type="text"
+      [ngModel]="newLocale()"
+      (ngModelChange)="updateNewLocale($event)"
+      placeholder="de"
+    />
+    <button type="button" (click)="addLocale()">{{ 'builder.addLanguage' | translate }}</button>
+  </div>
+
+  <div class="stack-list">
+    @for (code of locales(); track code) {
+      <article class="sub-card">
+        <div class="editor-actions">
+          <h3>{{ code }}</h3>
+          <div class="editor-actions">
+            @if (code === defaultLocale()) {
+              <span>{{ 'builder.defaultLanguageLabel' | translate }}</span>
+            } @else {
+              <button type="button" class="secondary" (click)="setDefault(code)">{{ 'builder.setDefaultLanguage' | translate }}</button>
+              <button type="button" class="secondary" (click)="removeLocale(code)">{{ 'builder.removeLanguage' | translate }}</button>
+            }
+          </div>
+        </div>
+      </article>
+    }
+  </div>
+</section>
diff --git a/src/app/features/project-editor/sections/languages-section.component.ts b/src/app/features/project-editor/sections/languages-section.component.ts
new file mode 100644
index 0000000..276d4b7
--- /dev/null
+++ b/src/app/features/project-editor/sections/languages-section.component.ts
@@ -0,0 +1,41 @@
+import { ChangeDetectionStrategy, Component, computed, inject, signal } from '@angular/core';
+import { FormsModule } from '@angular/forms';
+import { ProjectEditorFacade } from '../facade/project-editor.facade';
+import { TranslatePipe } from '../../../i18n/translate.pipe';
+
+@Component({
+  selector: 'app-project-editor-languages-section',
+  standalone: true,
+  imports: [FormsModule, TranslatePipe],
+  templateUrl: './languages-section.component.html',
+  styleUrls: ['./section.shared.scss'],
+  changeDetection: ChangeDetectionStrategy.OnPush
+})
+export class ProjectEditorLanguagesSectionComponent {
+  private readonly facade = inject(ProjectEditorFacade);
+  readonly bootstrap = this.facade.bootstrap;
+  readonly locales = computed(() => this.bootstrap()?.localization.supportedLocales ?? []);
+  readonly defaultLocale = computed(() => this.bootstrap()?.localization.defaultLocale ?? '');
+  readonly newLocale = signal('');
+
+  updateNewLocale(value: string): void {
+    this.newLocale.set(value);
+  }
+
+  addLocale(): void {
+    const code = this.newLocale().trim();
+    if (!code) {
+      return;
+    }
+    this.facade.addLocale(code);
+    this.newLocale.set('');
+  }
+
+  removeLocale(code: string): void {
+    this.facade.removeLocale(code);
+  }
+
+  setDefault(code: string): void {
+    this.facade.setDefaultLocale(code);
+  }
+}
diff --git a/src/app/features/project-editor/services/locale-sync.service.ts b/src/app/features/project-editor/services/locale-sync.service.ts
new file mode 100644
index 0000000..5c0b63d
--- /dev/null
+++ b/src/app/features/project-editor/services/locale-sync.service.ts
@@ -0,0 +1,119 @@
+import { Injectable } from '@angular/core';
+import { BootstrapConfig, FooterNavigationGroupConfig, NavigationItemConfig, NavigationLocalizedText } from '../../../shared/models/config';
+
+type SyncMode = 'add' | 'remove';
+
+@Injectable({ providedIn: 'root' })
+export class LocaleSyncService {
+  addLocale(bootstrap: BootstrapConfig, locale: string): BootstrapConfig {
+    return this.sync(bootstrap, locale, 'add');
+  }
+
+  removeLocale(bootstrap: BootstrapConfig, locale: string): BootstrapConfig {
+    if (locale === bootstrap.localization.defaultLocale) {
+      return bootstrap;
+    }
+    return this.sync(bootstrap, locale, 'remove');
+  }
+
+  private sync(bootstrap: BootstrapConfig, rawLocale: string, mode: SyncMode): BootstrapConfig {
+    const locale = rawLocale.trim().toLowerCase();
+    if (!locale) {
+      return bootstrap;
+    }
+
+    const alreadyPresent = bootstrap.localization.supportedLocales.includes(locale);
+    if (mode === 'add' && alreadyPresent) {
+      return bootstrap;
+    }
+    if (mode === 'remove' && !alreadyPresent) {
+      return bootstrap;
+    }
+
+    const supportedLocales = mode === 'add'
+      ? [...bootstrap.localization.supportedLocales, locale]
+      : bootstrap.localization.supportedLocales.filter(existing => existing !== locale);
+
+    return {
+      ...bootstrap,
+      tenant: { ...bootstrap.tenant, supportedLocales },
+      localization: { ...bootstrap.localization, supportedLocales },
+      staticPages: this.syncStaticPages(bootstrap.staticPages, locale, mode),
+      navigation: {
+        ...bootstrap.navigation,
+        header: this.syncNavItems(bootstrap.navigation.header, locale, mode),
+        footer: this.syncFooterNav(bootstrap.navigation.footer, locale, mode),
+        sidebar: bootstrap.navigation.sidebar ? this.syncNavItems(bootstrap.navigation.sidebar, locale, mode) : bootstrap.navigation.sidebar,
+      },
+    };
+  }
+
+  private syncStaticPages(staticPages: BootstrapConfig['staticPages'], locale: string, mode: SyncMode): BootstrapConfig['staticPages'] {
+    if (!staticPages || Array.isArray(staticPages)) {
+      return staticPages;
+    }
+
+    return Object.fromEntries(
+      Object.entries(staticPages).map(([id, page]) => [id, {
+        ...page,
+        translations: this.syncRecord(page.translations, locale, mode, () => ({ title: '', html: '' })),
+      }])
+    );
+  }
+
+  private syncNavItems(items: NavigationItemConfig[], locale: string, mode: SyncMode): NavigationItemConfig[] {
+    return items.map(item => ({
+      ...item,
+      label: this.syncLabel(item.label, locale, mode),
+      children: item.children ? this.syncNavItems(item.children, locale, mode) : item.children,
+    }));
+  }
+
+  private syncFooterNav(
+    footer: NavigationItemConfig[] | FooterNavigationGroupConfig[],
+    locale: string,
+    mode: SyncMode
+  ): NavigationItemConfig[] | FooterNavigationGroupConfig[] {
+    if (footer.length === 0) {
+      return footer;
+    }
+
+    if ('items' in footer[0]) {
+      return (footer as FooterNavigationGroupConfig[]).map(group => ({
+        ...group,
+        groupTitle: this.syncLabel(group.groupTitle, locale, mode),
+        items: group.items.map(item => ({ ...item, label: this.syncLabel(item.label, locale, mode) })),
+      }));
+    }
+
+    return this.syncNavItems(footer as NavigationItemConfig[], locale, mode);
+  }
+
+  private syncLabel(
+    label: string | NavigationLocalizedText | undefined,
+    locale: string,
+    mode: SyncMode
+  ): string | NavigationLocalizedText | undefined {
+    if (label === undefined || typeof label === 'string') {
+      return label;
+    }
+    return this.syncRecord(label, locale, mode, () => Object.values(label)[0] ?? '');
+  }
+
+  private syncRecord<T>(
+    record: Record<string, T> | undefined,
+    locale: string,
+    mode: SyncMode,
+    createEmpty: () => T
+  ): Record<string, T> {
+    const next: Record<string, T> = { ...(record ?? {}) };
+    if (mode === 'add') {
+      if (!(locale in next)) {
+        next[locale] = createEmpty();
+      }
+    } else {
+      delete next[locale];
+    }
+    return next;
+  }
+}
diff --git a/src/app/i18n/en.ts b/src/app/i18n/en.ts
index 1ace371..175eed7 100644
--- a/src/app/i18n/en.ts
+++ b/src/app/i18n/en.ts
@@ -485,6 +485,11 @@ export const en: Translations = {
     searchSuggestions: 'Search Suggestions',
     searchHistory: 'Search History',
     livePreview: 'Live Preview',
+    languagesTab: 'Languages',
+    addLanguage: 'Add Language',
+    removeLanguage: 'Remove',
+    setDefaultLanguage: 'Set as Default',
+    defaultLanguageLabel: 'Default',
     exportBootstrap: 'Export Bootstrap',
     importBootstrap: 'Import Bootstrap',
     exportedBootstrap: 'Exported Bootstrap',
diff --git a/src/app/i18n/hy.ts b/src/app/i18n/hy.ts
index e16b485..6e2dc32 100644
--- a/src/app/i18n/hy.ts
+++ b/src/app/i18n/hy.ts
@@ -485,6 +485,11 @@ export const hy: Translations = {
     searchSuggestions: 'Որոնման առաջարկներ',
     searchHistory: 'Որոնման պատմություն',
     livePreview: 'Կենդանի preview',
+    languagesTab: 'Լեզուներ',
+    addLanguage: 'Ավելացնել լեզու',
+    removeLanguage: 'Հեռացնել',
+    setDefaultLanguage: 'Դարձնել լռելյայն',
+    defaultLanguageLabel: 'Լռելյայն',
     exportBootstrap: 'Արտահանել bootstrap',
     importBootstrap: 'Ներմուծել bootstrap',
     exportedBootstrap: 'Արտահանված bootstrap',
diff --git a/src/app/i18n/ru.ts b/src/app/i18n/ru.ts
index f8262c2..bea94ed 100644
--- a/src/app/i18n/ru.ts
+++ b/src/app/i18n/ru.ts
@@ -485,6 +485,11 @@ export const ru: Translations = {
     searchSuggestions: 'Поисковые подсказки',
     searchHistory: 'История поиска',
     livePreview: 'Живое превью',
+    languagesTab: 'Языки',
+    addLanguage: 'Добавить язык',
+    removeLanguage: 'Удалить',
+    setDefaultLanguage: 'Сделать языком по умолчанию',
+    defaultLanguageLabel: 'По умолчанию',
     exportBootstrap: 'Экспорт bootstrap',
     importBootstrap: 'Импорт bootstrap',
     exportedBootstrap: 'Экспортированный bootstrap',
diff --git a/src/app/i18n/translations.ts b/src/app/i18n/translations.ts
index d7fa0cc..742dab3 100644
--- a/src/app/i18n/translations.ts
+++ b/src/app/i18n/translations.ts
@@ -483,6 +483,11 @@ export interface Translations {
     searchSuggestions: string;
     searchHistory: string;
     livePreview: string;
+    languagesTab: string;
+    addLanguage: string;
+    removeLanguage: string;
+    setDefaultLanguage: string;
+    defaultLanguageLabel: string;
     exportBootstrap: string;
     importBootstrap: string;
     exportedBootstrap: string;