diff --git a/frontend/index.html b/frontend/index.html
index adea8db..7e7f5c3 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -393,6 +393,7 @@ const state = {
   currentUser: null, // {id, username, role}
   authWarnings: {}, // source_slug → {source_slug, source_name}
   metaUpdating: new Set(), // urls where meta refresh is in progress
+  validating: {},          // url → {checked, total} for in-progress validations
 };
 
 // ── Auth ─────────────────────────────────────
@@ -703,6 +704,31 @@ function handleEvent(msg) {
       _updateMetaBtn(msg.url, msg.failed === -1 ? 'error' : 'done');
       break;
 
+    case 'validate_started':
+      state.validating[msg.url] = {checked: 0, total: 0};
+      _updateValidateBtn(msg.url);
+      break;
+
+    case 'validate_progress':
+      if(state.validating[msg.url]) {
+        state.validating[msg.url].checked = msg.checked;
+        state.validating[msg.url].total = msg.total;
+      }
+      _updateValidateBtn(msg.url);
+      break;
+
+    case 'validate_done': {
+      delete state.validating[msg.url];
+      const result = msg.total_to_redownload > 0 || msg.new_chapters > 0 ? 'issues' : 'ok';
+      _updateValidateBtn(msg.url, result, msg);
+      break;
+    }
+
+    case 'validate_error':
+      delete state.validating[msg.url];
+      _updateValidateBtn(msg.url, 'error');
+      break;
+
     case 'manga_meta_updated':
       if(state.mangas[msg.url]) {
         state.mangas[msg.url].title = msg.title;
@@ -1691,6 +1717,63 @@ async function refreshMetaModal(url) {
   // Спиннер появится через WS meta_refresh_started, исчезнет через meta_refreshed
 }
 
+function _updateValidateBtn(url, result, data) {
+  const modal = document.getElementById('modal');
+  if(!modal || modal.classList.contains('hidden') || modal.dataset.currentUrl !== url) return;
+  const btn = document.getElementById('modal-validate-btn');
+  if(!btn) return;
+  const v = state.validating[url];
+  if(v !== undefined) {
+    const prog = v.total > 0 ? ` ${v.checked}/${v.total}` : '...';
+    btn.innerHTML = `<span class="meta-spinner"></span> Проверка${prog}`;
+    btn.disabled = true;
+    btn.style.color = '#94a3b8';
+    btn.style.borderColor = '#334155';
+  } else if(result === 'ok') {
+    btn.innerHTML = '✅ Всё в порядке';
+    btn.disabled = false;
+    btn.style.color = '#4ade80';
+    btn.style.borderColor = '#166534';
+    setTimeout(() => { btn.innerHTML = '🔍 Проверить целостность'; btn.style.color='#67e8f9'; btn.style.borderColor='#164e63'; btn.disabled=false; }, 3000);
+  } else if(result === 'issues') {
+    const n = data ? (data.total_to_redownload + data.new_chapters) : '?';
+    btn.innerHTML = `⚡ Найдено проблем: ${n} — поставлено в очередь`;
+    btn.disabled = true;
+    btn.style.color = '#fbbf24';
+    btn.style.borderColor = '#78350f';
+    setTimeout(() => { btn.innerHTML = '🔍 Проверить целостность'; btn.style.color='#67e8f9'; btn.style.borderColor='#164e63'; btn.disabled=false; }, 5000);
+  } else if(result === 'error') {
+    btn.innerHTML = '❌ Ошибка валидации';
+    btn.disabled = false;
+    btn.style.color = '#f87171';
+    btn.style.borderColor = '#7f1d1d';
+    setTimeout(() => { btn.innerHTML = '🔍 Проверить целостность'; btn.style.color='#67e8f9'; btn.style.borderColor='#164e63'; btn.disabled=false; }, 3000);
+  } else {
+    btn.innerHTML = '🔍 Проверить целостность';
+    btn.disabled = false;
+    btn.style.color = '#67e8f9';
+    btn.style.borderColor = '#164e63';
+  }
+}
+
+async function validateManga(url) {
+  const btn = document.getElementById('modal-validate-btn');
+  if(btn) {
+    btn.innerHTML = '<span class="meta-spinner"></span> Запуск...';
+    btn.disabled = true;
+  }
+  const r = await fetch('/api/mangas/validate?url='+encodeURIComponent(url), {method:'POST'});
+  if(!r.ok) {
+    const err = await r.json().catch(() => ({}));
+    if(btn) {
+      btn.innerHTML = '❌ ' + (err.detail || 'Ошибка');
+      btn.style.color = '#f87171';
+      btn.style.borderColor = '#7f1d1d';
+      setTimeout(() => { btn.innerHTML = '🔍 Проверить целостность'; btn.style.color='#67e8f9'; btn.style.borderColor='#164e63'; btn.disabled=false; }, 3000);
+    }
+  }
+}
+
 async function forceRedownload(url, closeModalAfter = false) {
   if(!confirm('Скачать заново ВСЕ главы? Уже скачанные файлы будут перезаписаны.')) return;
   const r = await fetch('/api/mangas/force_redownload?url='+encodeURIComponent(url), {method:'POST'});
@@ -2233,6 +2316,15 @@ function renderModalBody(data) {
           📁 Переименовать папку
         </button>` : ''}
         ${data.status === 'done' && canManage(data) ? `
+        <button id="modal-validate-btn" onclick="validateManga('${escHtml(data.url)}')"
+          class="flex items-center gap-2 px-4 py-2 rounded-lg text-sm font-semibold transition-colors"
+          style="background:#0c1a2e;color:#67e8f9;border:1px solid #164e63"
+          ${state.validating[data.url] !== undefined ? 'disabled' : ''}>
+          ${state.validating[data.url] !== undefined
+            ? `<span class="meta-spinner"></span> Проверка${state.validating[data.url].total > 0 ? ' '+state.validating[data.url].checked+'/'+state.validating[data.url].total : '...'}`
+            : '🔍 Проверить целостность'}
+        </button>` : ''}
+        ${data.status === 'done' && canManage(data) ? `
         <button id="modal-refresh-meta-btn" onclick="refreshMetaModal('${escHtml(data.url)}')"
           class="flex items-center gap-2 px-4 py-2 rounded-lg text-sm font-semibold transition-colors"
           style="background:#1e1b4b;color:#a78bfa;border:1px solid #312e81">
diff --git a/src/api.py b/src/api.py
index 864c804..24c14f7 100644
--- a/src/api.py
+++ b/src/api.py
@@ -16,7 +16,7 @@ from fastapi.staticfiles import StaticFiles
 from pydantic import BaseModel
 from loguru import logger
 from .state import StateDB
-from .worker import download_manga, check_for_updates
+from .worker import download_manga, check_for_updates, validate_manga
 from .browser import BrowserManager
 from .exporter import patch_meta, MangaMeta
 from .sources import registry, get_source_for_url, extract_domain
@@ -849,6 +849,44 @@ async def force_redownload(url: str, _: dict = Depends(require_admin)):
         return {"ok": True}
     finally:
         db.close()
+@app.post("/api/mangas/validate")
+async def validate_manga_endpoint(url: str, current_user: dict = Depends(get_current_user)):
+    db = StateDB()
+    try:
+        manga = db.get_manga(url)
+        if not manga:
+            raise HTTPException(status_code=404, detail="Манга не найдена")
+        if manga["status"] != "done":
+            raise HTTPException(status_code=400, detail="Валидация доступна только для манг в статусе 'Готово'")
+        _check_manga_access(manga, current_user)
+    finally:
+        db.close()
+    asyncio.create_task(_do_validate(url))
+    return {"ok": True}
+async def _do_validate(url: str):
+    db = StateDB()
+    try:
+        manga = db.get_manga(url)
+        fmt = manga["format"] if manga else "cbz"
+    finally:
+        db.close()
+    result = await validate_manga(url, on_event=ws_manager.broadcast)
+    if not result.get("ok"):
+        return
+    chapters_to_retry = result.get("chapters_to_redownload", [])
+    new_chapters = result.get("new_chapters", 0)
+    if not chapters_to_retry and not new_chapters:
+        return
+    db2 = StateDB()
+    try:
+        for chapter_url in chapters_to_retry:
+            db2.reset_chapter(chapter_url)
+        db2.update_manga_status(url, "queued")
+    finally:
+        db2.close()
+    await download_queue.put({"url": url, "fmt": fmt})
+    await ws_manager.broadcast({"type": "manga_queued", "url": url, "format": fmt})
+    await _broadcast_queue_positions()
 @app.post("/api/mangas/stop")
 async def stop_manga(url: str, current_user: dict = Depends(get_current_user)):
     db = StateDB()
diff --git a/src/sources/mangalib.py b/src/sources/mangalib.py
index 0f43362..c2d8cb0 100644
--- a/src/sources/mangalib.py
+++ b/src/sources/mangalib.py
@@ -382,6 +382,59 @@ class MangalibSource:
 
         return [paths[i] for i in sorted(paths.keys())]
 
+    async def get_chapter_page_count(
+        self, page: Page, chapter_url: str, manga_url: Optional[str] = None
+    ) -> int:
+        """Открывает главу и возвращает количество страниц через API без скачивания изображений."""
+        pages_info: list = []
+        auth_err: list = []
+        lock = asyncio.Lock()
+
+        async def on_response(resp):
+            try:
+                if "api.cdnlibs.org" in resp.url and "/chapter?" in resp.url:
+                    if resp.status in (401, 403):
+                        auth_err.append(True)
+                        return
+                    body = await resp.body()
+                    data = _json.loads(body)
+                    async with lock:
+                        if not pages_info:
+                            pages_info.extend(data.get("data", {}).get("pages", []))
+            except Exception:
+                pass
+
+        if self.auth_token:
+            await page.set_extra_http_headers({"Authorization": f"Bearer {self.auth_token}"})
+        page.on("response", on_response)
+
+        referer = manga_url or _base_url(chapter_url)
+        ok = await _navigate(page, chapter_url, referer=referer)
+        if not ok:
+            mirror_url = _switch_to_mirror(chapter_url)
+            if mirror_url != chapter_url:
+                ok = await _navigate(
+                    page, mirror_url,
+                    referer=_switch_to_mirror(referer) if referer else referer,
+                )
+
+        if not ok:
+            page.remove_listener("response", on_response)
+            return 0
+
+        for _ in range(40):
+            async with lock:
+                if pages_info or auth_err:
+                    break
+            await asyncio.sleep(0.5)
+
+        page.remove_listener("response", on_response)
+
+        if auth_err and not pages_info:
+            raise AuthRequiredError(self.slug)
+
+        return len(pages_info)
+
 
 # ──────────────────────────────────────────────
 # Вспомогательные функции (приватные)
diff --git a/src/sources/readmanga.py b/src/sources/readmanga.py
index a6d1255..0f1bb2d 100644
--- a/src/sources/readmanga.py
+++ b/src/sources/readmanga.py
@@ -376,6 +376,19 @@ class ReadmangaSource:
 
         return [paths[i] for i in sorted(paths.keys())]
 
+    async def get_chapter_page_count(
+        self, page: Page, chapter_url: str, manga_url: Optional[str] = None
+    ) -> int:
+        """Открывает главу и возвращает количество страниц без скачивания изображений."""
+        load_url = chapter_url + ("?mtr=1" if "?" not in chapter_url else "&mtr=1")
+        ok = await _navigate(page, load_url)
+        if not ok:
+            return 0
+        urls = await _extract_images_from_js(page)
+        if not urls:
+            urls = await _extract_images_from_dom(page)
+        return len(urls)
+
 
 # ──────────────────────────────────────────────
 # Вспомогательные функции (приватные)
diff --git a/src/worker.py b/src/worker.py
index cef844c..37c1dd2 100644
--- a/src/worker.py
+++ b/src/worker.py
@@ -406,6 +406,207 @@ async def download_manga(
         db.close()
 
 
+async def validate_manga(
+    url: str,
+    output_dir: Path = OUTPUT_DIR,
+    on_event=None,
+) -> dict:
+    """
+    Проверяет целостность скачанной манги, сравнивая с сайтом.
+
+    - Получает актуальный список глав с сайта
+    - Добавляет новые главы в БД
+    - Для скачанных глав: проверяет наличие файлов и количество страниц
+    - Возвращает dict с chapters_to_redownload и статистикой
+    """
+
+    async def emit(event: dict):
+        if on_event:
+            try:
+                await on_event(event)
+            except Exception as e:
+                logger.debug("on_event error: {}", e)
+
+    db = StateDB()
+    db_lock = asyncio.Lock()
+
+    async def db_call(fn, *args, **kwargs):
+        async with db_lock:
+            return fn(*args, **kwargs)
+
+    try:
+        await emit({"type": "validate_started", "url": url})
+
+        source = get_source_for_url(url, db)
+        if source is None:
+            manga_row = await db_call(db.get_manga, url)
+            if manga_row and manga_row.get("source_id"):
+                source = registry.get_by_db_id(manga_row["source_id"], db)
+        if source is None:
+            await emit({"type": "validate_error", "url": url,
+                        "error": "Источник не определён. Выберите источник в настройках манги."})
+            return {"ok": False, "chapters_to_redownload": []}
+
+        if hasattr(source, "auth_token"):
+            _src_row = await db_call(db.get_source_by_slug, source.slug)
+            if _src_row:
+                _settings_raw = _src_row.get("settings") or "{}"
+                try:
+                    _settings = _json.loads(_settings_raw) if isinstance(_settings_raw, str) else (_settings_raw or {})
+                except Exception:
+                    _settings = {}
+                source.auth_token = _settings.get("auth_token") or None
+
+        manga_row = await db_call(db.get_manga, url)
+        fmt = (manga_row or {}).get("format", "cbz")
+        fmt_list = ["cbz", "pdf", "epub"] if fmt == "all" else [fmt]
+
+        async with BrowserManager(headless=True) as bm:
+            ctx, info_page = await bm.new_page()
+            try:
+                manga = await source.get_manga_info(info_page, url)
+            except Exception as e:
+                logger.error("validate: get_manga_info ошибка для {}: {}", url, e)
+                await emit({"type": "validate_error", "url": url, "error": str(e)})
+                return {"ok": False, "chapters_to_redownload": []}
+            finally:
+                await info_page.close()
+
+            if not manga:
+                await emit({"type": "validate_error", "url": url,
+                            "error": "Не удалось получить информацию о манге с сайта"})
+                return {"ok": False, "chapters_to_redownload": []}
+
+            for ch in manga.chapters:
+                await db_call(db.upsert_chapter, url, ch.url, ch.title, ch.number, ch.volume)
+
+            all_ch_rows = await db_call(db.get_all_chapters, url)
+            db_chapters = {c["chapter_url"]: c for c in all_ch_rows}
+
+            new_chapters = [
+                ch for ch in manga.chapters
+                if db_chapters.get(ch.url, {}).get("status") == "pending"
+            ]
+
+            done_chapters = [
+                ch for ch in manga.chapters
+                if db_chapters.get(ch.url, {}).get("status") == "done"
+            ]
+
+            to_redownload: set = set()
+            fast_issues = 0
+
+            for ch in done_chapters:
+                db_ch = db_chapters[ch.url]
+                if db_ch.get("pages_total", 0) > 0 and db_ch.get("pages_done", 0) < db_ch["pages_total"]:
+                    to_redownload.add(ch.url)
+                    fast_issues += 1
+                    continue
+                for f in fmt_list:
+                    fpath = db_ch.get(f"output_{f}")
+                    if fpath and not Path(fpath).exists():
+                        to_redownload.add(ch.url)
+                        fast_issues += 1
+                        break
+
+            chapters_for_deep = [
+                ch for ch in done_chapters if ch.url not in to_redownload
+            ]
+            site_mismatched = 0
+            checked = 0
+            has_page_count = hasattr(source, "get_chapter_page_count")
+
+            if has_page_count and chapters_for_deep:
+                sem = asyncio.Semaphore(2)
+                count_lock = asyncio.Lock()
+
+                async def check_one(ch: Chapter) -> None:
+                    nonlocal checked, site_mismatched
+                    async with sem:
+                        db_ch = db_chapters[ch.url]
+                        ch_page = await ctx.new_page()
+                        mismatch = False
+                        site_count = 0
+                        try:
+                            site_count = await source.get_chapter_page_count(
+                                ch_page, ch.url, url
+                            )
+                        except AuthRequiredError:
+                            raise
+                        except Exception as e:
+                            logger.warning(
+                                "validate page count Т{} Гл.{}: {}", ch.volume, ch.number, e
+                            )
+                        finally:
+                            await ch_page.close()
+
+                        pages_have = db_ch.get("pages_done", 0)
+                        if site_count > 0 and site_count != pages_have:
+                            mismatch = True
+                            logger.info(
+                                "validate: Т{} Гл.{} — сайт {} стр., у нас {} → повтор",
+                                ch.volume, ch.number, site_count, pages_have,
+                            )
+
+                        async with count_lock:
+                            checked += 1
+                            if mismatch:
+                                to_redownload.add(ch.url)
+                                site_mismatched += 1
+
+                        await emit({
+                            "type": "validate_progress",
+                            "url": url,
+                            "checked": checked,
+                            "total": len(chapters_for_deep),
+                            "chapter_number": ch.number,
+                            "volume": ch.volume,
+                            "mismatch": mismatch,
+                            "site_count": site_count,
+                        })
+
+                results = await asyncio.gather(
+                    *[check_one(ch) for ch in chapters_for_deep],
+                    return_exceptions=True,
+                )
+                auth_slug = None
+                for res in results:
+                    if isinstance(res, AuthRequiredError):
+                        auth_slug = res.source_slug
+                    elif isinstance(res, Exception) and not isinstance(res, asyncio.CancelledError):
+                        logger.exception("validate gather exception: {}", res)
+                if auth_slug:
+                    await emit({"type": "validate_error", "url": url,
+                                "error": f"auth_required:{auth_slug}"})
+                    return {"ok": False, "chapters_to_redownload": []}
+
+            to_redownload_list = list(to_redownload)
+            result = {
+                "ok": True,
+                "url": url,
+                "site_chapters": len(manga.chapters),
+                "new_chapters": len(new_chapters),
+                "fast_issues": fast_issues,
+                "site_mismatched": site_mismatched,
+                "total_to_redownload": len(to_redownload_list),
+                "chapters_to_redownload": to_redownload_list,
+            }
+            await emit({
+                "type": "validate_done",
+                **{k: v for k, v in result.items() if k != "chapters_to_redownload"},
+            })
+            return result
+
+    except asyncio.CancelledError:
+        raise
+    except Exception as e:
+        logger.error("validate_manga {}: {}", url, e)
+        await emit({"type": "validate_error", "url": url, "error": str(e)})
+        return {"ok": False, "chapters_to_redownload": []}
+    finally:
+        db.close()
+
+
 def _cover_ext_from_url(url: str) -> str:
     import re as _re
     m = _re.search(r"\.(jpg|jpeg|png|webp)(\?|$)", url, _re.IGNORECASE)