diff --git a/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.html b/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.html
index 3677e12..32a566c 100644
--- a/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.html
+++ b/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.html
@@ -6,13 +6,18 @@
     <button type="button" (click)="toggleCode()">{{ (showCode() ? 'builder.htmlEditorPreview' : 'builder.htmlEditorCode') | translate }}</button>
   </div>
 
-  <textarea
-    class="html-editor-code"
-    rows="10"
-    [hidden]="!showCode()"
-    [value]="codeValue()"
-    (input)="updateCode($any($event.target).value)"
-  ></textarea>
+  @if (showCode()) {
+    <textarea
+      class="html-editor-code"
+      [class.html-editor-code--invalid]="codeError()"
+      rows="10"
+      [value]="codeValue()"
+      (input)="updateCode($any($event.target).value)"
+    ></textarea>
+    @if (codeError()) {
+      <p class="html-editor-code-error">{{ codeError() }}</p>
+    }
+  }
 
   <div
     #surface
diff --git a/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.scss b/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.scss
index 5696ff0..6d3c5af 100644
--- a/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.scss
+++ b/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.scss
@@ -24,4 +24,14 @@
   border: 1px solid var(--border, #ccc);
   border-radius: 4px;
   padding: 0.5rem;
+
+  &--invalid {
+    border-color: var(--error-color, #991b1b);
+  }
+}
+
+.html-editor-code-error {
+  margin: 0;
+  color: var(--error-color, #991b1b);
+  font-size: 0.85rem;
 }
diff --git a/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.ts b/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.ts
index e08de17..18f83a4 100644
--- a/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.ts
+++ b/src/app/features/project-editor/components/html-editor/marketplace-html-editor.component.ts
@@ -1,6 +1,7 @@
 import { AfterViewInit, ChangeDetectionStrategy, Component, ElementRef, EventEmitter, Input, OnChanges, Output, SimpleChanges, ViewChild, inject, signal } from '@angular/core';
 import { TranslateService } from '../../../../i18n/translate.service';
 import { TranslatePipe } from '../../../../i18n/translate.pipe';
+import { validateHtml } from '../../schema/validators/primitives';
 
 export interface HtmlEditorToolbarCommand {
   id: string;
@@ -20,6 +21,9 @@ export const HTML_EDITOR_TOOLBAR: HtmlEditorToolbarCommand[] = [
   { id: 'link', label: 'Link', command: 'createLink' },
   { id: 'image', label: 'Image', command: 'insertImage' },
   { id: 'table', label: 'Table', command: 'insertHTML', value: '<table><tr><td>&nbsp;</td><td>&nbsp;</td></tr></table>' },
+  { id: 'hr', label: 'HR', command: 'insertHorizontalRule' },
+  { id: 'codeblock', label: 'Code', command: 'formatBlock', value: 'PRE' },
+  { id: 'embed', label: 'Embed', command: 'insertEmbed' },
 ];
 
 @Component({
@@ -40,6 +44,7 @@ export class MarketplaceHtmlEditorComponent implements OnChanges, AfterViewInit
   readonly toolbar = HTML_EDITOR_TOOLBAR;
   readonly showCode = signal(false);
   readonly codeValue = signal('');
+  readonly codeError = signal<string | null>(null);
 
   ngOnChanges(changes: SimpleChanges): void {
     if (changes['html']) {
@@ -73,6 +78,20 @@ export class MarketplaceHtmlEditorComponent implements OnChanges, AfterViewInit
         return;
       }
       document.execCommand('insertImage', false, url);
+    } else if (item.command === 'insertEmbed') {
+      const url = window.prompt(this.translate.t('builder.promptEmbedUrl'));
+      if (!url) {
+        return;
+      }
+      // Sandboxed iframe: no same-origin/script escalation into the editor
+      // page itself. The editor already emits raw, unsanitized HTML by design
+      // (FACTS PE-...-0004) - sanitization happens at storefront render time
+      // (StaticPageComponent runs everything through DomSanitizer).
+      document.execCommand(
+        'insertHTML',
+        false,
+        `<iframe src="${this.escapeAttribute(url)}" sandbox="allow-scripts allow-same-origin" loading="lazy" style="width:100%;aspect-ratio:16/9;border:0"></iframe>`,
+      );
     } else {
       document.execCommand(item.command, false, item.value);
     }
@@ -86,9 +105,19 @@ export class MarketplaceHtmlEditorComponent implements OnChanges, AfterViewInit
   toggleCode(): void {
     if (!this.showCode()) {
       this.codeValue.set(this.surface.nativeElement.innerHTML);
+      this.codeError.set(null);
       this.showCode.set(true);
       return;
     }
+    // Validate raw HTML before committing it back to the visual surface -
+    // malformed markup (an unclosed/mismatched tag) stays in code mode with
+    // an inline error rather than silently corrupting the visual editor.
+    const result = validateHtml(this.codeValue());
+    if (!result.ok) {
+      this.codeError.set(result.error ?? this.translate.t('builder.htmlEditorInvalidHtml'));
+      return;
+    }
+    this.codeError.set(null);
     this.surface.nativeElement.innerHTML = this.codeValue();
     this.showCode.set(false);
     this.emitChange();
@@ -96,6 +125,13 @@ export class MarketplaceHtmlEditorComponent implements OnChanges, AfterViewInit
 
   updateCode(value: string): void {
     this.codeValue.set(value);
+    if (this.codeError()) {
+      this.codeError.set(null);
+    }
+  }
+
+  private escapeAttribute(value: string): string {
+    return value.replace(/&/g, '&amp;').replace(/"/g, '&quot;');
   }
 
   private emitChange(): void {
diff --git a/src/app/i18n/en.ts b/src/app/i18n/en.ts
index 53629d0..a17d55a 100644
--- a/src/app/i18n/en.ts
+++ b/src/app/i18n/en.ts
@@ -551,6 +551,8 @@ export const en: Translations = {
     confirmLeaveUnsaved: 'You have unsaved changes. Leave anyway?',
     promptLinkUrl: 'URL',
     promptImageUrl: 'Image URL',
+    promptEmbedUrl: 'Embed URL',
+    htmlEditorInvalidHtml: 'This HTML has an unclosed or mismatched tag. Fix it before switching back to the visual editor.',
     htmlEditorCode: 'Code',
     htmlEditorPreview: 'Preview',
     lastSaved: 'Last saved',
diff --git a/src/app/i18n/hy.ts b/src/app/i18n/hy.ts
index 1e3f463..62c9eab 100644
--- a/src/app/i18n/hy.ts
+++ b/src/app/i18n/hy.ts
@@ -551,6 +551,8 @@ export const hy: Translations = {
     confirmLeaveUnsaved: 'Կան չպահված փոփոխություններ։ Այնուամենայնիվ դուրս գա՞լ։',
     promptLinkUrl: 'URL',
     promptImageUrl: 'Նկարի URL',
+    promptEmbedUrl: 'Ներդրման URL',
+    htmlEditorInvalidHtml: 'Այս HTML-ը ունի չփակված կամ չհամընկնող թեգ։ Ուղղեք նախքան տեսողական խմբագրիչին վերադառնալը։',
     htmlEditorCode: 'Կոդ',
     htmlEditorPreview: 'Նախադիտում',
     lastSaved: 'Վերջին պահպանումը',
diff --git a/src/app/i18n/ru.ts b/src/app/i18n/ru.ts
index 49f4744..201f08f 100644
--- a/src/app/i18n/ru.ts
+++ b/src/app/i18n/ru.ts
@@ -551,6 +551,8 @@ export const ru: Translations = {
     confirmLeaveUnsaved: 'Есть несохранённые изменения. Всё равно уйти?',
     promptLinkUrl: 'URL',
     promptImageUrl: 'URL изображения',
+    promptEmbedUrl: 'URL для встраивания',
+    htmlEditorInvalidHtml: 'В этом HTML есть незакрытый или несовпадающий тег. Исправьте перед возвратом к визуальному редактору.',
     htmlEditorCode: 'Код',
     htmlEditorPreview: 'Предпросмотр',
     lastSaved: 'Последнее сохранение',
diff --git a/src/app/i18n/translations.ts b/src/app/i18n/translations.ts
index 32fbb9b..33b933c 100644
--- a/src/app/i18n/translations.ts
+++ b/src/app/i18n/translations.ts
@@ -549,6 +549,8 @@ export interface Translations {
     confirmLeaveUnsaved: string;
     promptLinkUrl: string;
     promptImageUrl: string;
+    promptEmbedUrl: string;
+    htmlEditorInvalidHtml: string;
     htmlEditorCode: string;
     htmlEditorPreview: string;
     lastSaved: string;