diff --git a/backend/src/__tests__/galleryOgService.shareImage.test.js b/backend/src/__tests__/galleryOgService.shareImage.test.js
index fd5f8b2e..3f10efdb 100644
--- a/backend/src/__tests__/galleryOgService.shareImage.test.js
+++ b/backend/src/__tests__/galleryOgService.shareImage.test.js
@@ -343,12 +343,34 @@ describe('isSocialCrawler — extended bot coverage (#521)', () => {
       // 3rd-party preview services used by business-messaging stacks
       'LinkPreview/1.0',
       'Slack-ImgProxy/1.0',
+      // Viber + broader crawler set (#699 follow-up)
+      'Mozilla/5.0 (compatible; Viber)',
+      'Mozilla/5.0 (compatible; Bluesky Cardyb/1.1)',
+      'facebookcatalog/1.0',
+      'kakaotalk-scrap/1.0',
+      'Mozilla/5.0 (compatible; Synapse/1.98)',
+      'Rocket.Chat/6.0',
     ];
     for (const ua of knownBots) {
       expect(isSocialCrawler(ua)).toBe(true);
     }
   });
 
+  it('does NOT match human in-app-browser UAs (our OG response is meta-only, no redirect)', () => {
+    // These share a token with a preview bot but are also sent by real users
+    // browsing inside the app's webview — matching them would serve a human
+    // the bare OG stub. Deliberately excluded; guard against re-adding them.
+    const inAppBrowsers = [
+      'Mozilla/5.0 (iPhone) AppleWebKit MicroMessenger/8.0.0',        // WeChat in-app
+      'Mozilla/5.0 (iPhone) AppleWebKit Line/13.0.0',                // LINE in-app
+      'Mozilla/5.0 (Linux; Android) Zalo',                          // Zalo in-app
+      'Mozilla/5.0 (Macintosh) Chrome/120.0 Safari/537.36 boxing',  // "XING" substring trap
+    ];
+    for (const ua of inAppBrowsers) {
+      expect(isSocialCrawler(ua)).toBe(false);
+    }
+  });
+
   it('does not match a regular browser UA', () => {
     const browsers = [
       'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0 Safari/537.36',
diff --git a/backend/src/services/galleryOgService.js b/backend/src/services/galleryOgService.js
index a1ed8ef9..5cac9cf6 100644
--- a/backend/src/services/galleryOgService.js
+++ b/backend/src/services/galleryOgService.js
@@ -34,7 +34,29 @@ const SOCIAL_CRAWLER_PATTERNS = [
   // messaging stacks (Twilio, LinkPreview.net, etc.). Match the
   // canonical lowercase substring; the /i flag handles case.
   /LinkPreview/i,
-  /Slack-ImgProxy/i
+  /Slack-ImgProxy/i,
+  // Viber's link-preview fetcher — was never detected, so shared links
+  // showed no rich preview in Viber (#699 follow-up). Keep in sync with the
+  // UA list in frontend/nginx.conf.
+  /Viber/i,
+  // Broader crawler coverage (#699 follow-up, from alexvaltchev's field list).
+  // IMPORTANT: only CRAWLER-EXCLUSIVE tokens are added here. Our OG response is
+  // meta-only (no client redirect), so a UA shared with a real human in-app
+  // browser would serve that human the bare stub. That rules out WeChat
+  // (MicroMessenger), LINE (Line/), Zalo, and generic strings like
+  // "InAppBrowser"/"preview"/"unfurl" — deliberately NOT added.
+  /Cardyb/i, // Bluesky's link-card service (the actual fetcher UA)
+  /facebookcatalog/i, // Facebook catalog crawler
+  /Signal/i, // Signal link preview
+  /Misskey/i, // fediverse (server-side preview fetch)
+  /Pleroma/i, // fediverse
+  /Synapse/i, // Matrix homeserver URL preview
+  /Nextcloud/i, // Nextcloud Talk/News link crawler
+  /Rocket\.Chat/i, // Rocket.Chat server preview
+  /kakaotalk-scrap/i, // KakaoTalk's scraper (NOT the in-app browser UA)
+  /Google-PageRenderer/i, // Google Chat previews (not Search)
+  /OdklBot/i, // Odnoklassniki
+  /ZoomBot/i // Zoom Team Chat
 ];
 
 function isSocialCrawler(userAgent) {
diff --git a/frontend/nginx.conf b/frontend/nginx.conf
index 45175a03..442a4306 100644
--- a/frontend/nginx.conf
+++ b/frontend/nginx.conf
@@ -237,12 +237,25 @@ server {
     # Facebook, Slack, Twitter, etc.) don't run JS, so the SPA's client-side
     # meta tags never reach them. Route those UAs to backend's /og handler
     # via internal rewrite; humans fall through to the SPA via try_files.
-    location ~ ^/gallery/(?<gallery_slug>[A-Za-z0-9_-]+)(?:/[^/]+)?/?$ {
+    # {0,2} extra path segments so the deeper gallery share shapes match too:
+    #   /gallery/<slug>                      (public / share-token link)
+    #   /gallery/<slug>/client-access        (client-access; token is in ?query)
+    #   /gallery/<slug>/show/<token>          (slideshow; token is a PATH segment)
+    # The slideshow shape has TWO extra segments (show + token) — the old
+    # single-segment `(?:/[^/]+)?` never matched it, so slideshow links fell
+    # through to the SPA and got only the generic site-wide OG (#699 follow-up).
+    # NB: the regex is QUOTED because the {0,2} quantifier's braces would
+    # otherwise be parsed as nginx config block delimiters.
+    location ~ "^/gallery/(?<gallery_slug>[A-Za-z0-9_-]+)(?:/[^/]+){0,2}/?$" {
         # Keep this list in sync with SOCIAL_CRAWLER_PATTERNS in
         # backend/src/services/galleryOgService.js. WhatsAppBot / wa-bot
         # and LinkPreview / Slack-ImgProxy added in #521 to catch
         # business-API preview fetchers that aren't the main WhatsApp app.
-        if ($http_user_agent ~* "(facebookexternalhit|facebot|Twitterbot|WhatsApp|WhatsAppBot|wa-bot|Slackbot|Slack-ImgProxy|TelegramBot|SkypeUriPreview|Discordbot|LinkedInBot|Pinterest|vkShare|redditbot|Embedly|iframely|Snapchat|Applebot|Mastodon|Bluesky|OpenGraph|LinkPreview)") {
+        # Viber + the broader set below added in #699 follow-up. Only
+        # CRAWLER-EXCLUSIVE tokens — the backend OG response is meta-only (no
+        # redirect), so UAs shared with real human in-app browsers (WeChat's
+        # MicroMessenger, LINE's "Line/", Zalo, "InAppBrowser") are NOT added.
+        if ($http_user_agent ~* "(facebookexternalhit|facebookcatalog|facebot|Twitterbot|WhatsApp|WhatsAppBot|wa-bot|Slackbot|Slack-ImgProxy|TelegramBot|SkypeUriPreview|Discordbot|LinkedInBot|Pinterest|vkShare|redditbot|Embedly|iframely|Snapchat|Applebot|Mastodon|Bluesky|Cardyb|OpenGraph|LinkPreview|Viber|Signal|Misskey|Pleroma|Synapse|Nextcloud|Rocket\.Chat|kakaotalk-scrap|Google-PageRenderer|OdklBot|ZoomBot)") {
             rewrite ^ /og/gallery/$gallery_slug last;
         }
         try_files $uri $uri/ /index.html;
@@ -260,6 +273,22 @@ server {
         proxy_set_header X-Forwarded-Proto $real_proto;
     }
 
+    # Branded URL shortener (#699). The backend `/s/<short_slug>` route both
+    # 302-redirects humans to the target gallery AND server-renders OG for
+    # social crawlers. Without this proxy, `/s/...` fell through to the SPA
+    # (which has no /s/ route) — so branded short links were dead for humans
+    # and crawlers alike. `^~` beats the regex SPA fallback below. The backend
+    # does its own UA detection, so no crawler `if` is needed here.
+    location ^~ /s/ {
+        set $backend_upstream backend;
+        proxy_pass http://$backend_upstream:3000;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $real_proto;
+    }
+
     # SPA fallback
     location / {
         try_files $uri $uri/ /index.html;