diff --git a/app/Http/Kernel.php b/app/Http/Kernel.php
index 33e2c42f8ecd..e788bd0fb71d 100644
--- a/app/Http/Kernel.php
+++ b/app/Http/Kernel.php
@@ -30,6 +30,7 @@ use App\Http\Middleware\QueryLogging;
 use App\Http\Middleware\RedirectIfAuthenticated;
 use App\Http\Middleware\SetDb;
 use App\Http\Middleware\SetDbByCompanyKey;
+use App\Http\Middleware\SetDocumentDb;
 use App\Http\Middleware\SetDomainNameDb;
 use App\Http\Middleware\SetEmailDb;
 use App\Http\Middleware\SetInviteDb;
@@ -158,6 +159,7 @@ class Kernel extends HttpKernel
         'contact_key_login' => ContactKeyLogin::class,
         'check_client_existence' => CheckClientExistence::class,
         'user_verified' => UserVerified::class,
+        'document_db' => SetDocumentDb::class,
     ];
 
 
diff --git a/app/Http/Middleware/SetDocumentDb.php b/app/Http/Middleware/SetDocumentDb.php
new file mode 100644
index 000000000000..83d0d0be88bd
--- /dev/null
+++ b/app/Http/Middleware/SetDocumentDb.php
@@ -0,0 +1,44 @@
+<?php
+/**
+ * Invoice Ninja (https://invoiceninja.com).
+ *
+ * @link https://github.com/invoiceninja/invoiceninja source repository
+ *
+ * @copyright Copyright (c) 2021. Invoice Ninja LLC (https://invoiceninja.com)
+ *
+ * @license https://www.elastic.co/licensing/elastic-license
+ */
+
+namespace App\Http\Middleware;
+
+use App\Libraries\MultiDB;
+use Closure;
+use Illuminate\Http\Request;
+use stdClass;
+
+class SetDocumentDb
+{
+    /**
+     * Handle an incoming request.
+     *
+     * @param  Request  $request
+     * @param Closure $next
+     * @return mixed
+     */
+    public function handle($request, Closure $next)
+    {
+        $error = [
+            'message' => 'Document not set or not found',
+            'errors' => new stdClass,
+        ];
+
+        if ($request->has('document_hash') && config('ninja.db.multi_db_enabled')) {
+            
+            if (! MultiDB::documentFindAndSetDb($request->input('document_hash'))) 
+                return response()->json($error, 400);
+            
+        }
+
+        return $next($request);
+    }
+}
diff --git a/app/Libraries/MultiDB.php b/app/Libraries/MultiDB.php
index 1847592d0f50..8120da08925d 100644
--- a/app/Libraries/MultiDB.php
+++ b/app/Libraries/MultiDB.php
@@ -206,6 +206,24 @@ class MultiDB
         return false;
     }
 
+    public static function documentFindAndSetDb($hash) : bool
+    {
+        $current_db = config('database.default');  
+
+        //multi-db active
+        foreach (self::$dbs as $db) {
+            
+            if (Document::on($db)->where('hash', $hash)->count() >= 1){ 
+                self::setDb($db);
+                return true;
+            }
+
+        }
+
+        self::setDB($current_db);
+        return false;
+    }
+
     public static function findAndSetDb($token) :bool
     {
         $current_db = config('database.default');  
diff --git a/routes/client.php b/routes/client.php
index 53e5e2626ad0..b95d5a95ded0 100644
--- a/routes/client.php
+++ b/routes/client.php
@@ -23,7 +23,7 @@ Route::get('tmp_pdf/{hash}', 'ClientPortal\TempRouteController@index')->name('tm
 
 Route::get('client/key_login/{contact_key}', 'ClientPortal\ContactHashLoginController@login')->name('client.contact_login')->middleware(['domain_db','contact_key_login']);
 Route::get('client/magic_link/{magic_link}', 'ClientPortal\ContactHashLoginController@magicLink')->name('client.contact_magic_link')->middleware(['domain_db','contact_key_login']);
-Route::get('documents/{document_hash}', 'ClientPortal\DocumentController@publicDownload')->name('documents.public_download');
+Route::get('documents/{document_hash}', 'ClientPortal\DocumentController@publicDownload')->name('documents.public_download')->middleware(['document_db']);
 Route::get('error', 'ClientPortal\ContactHashLoginController@errorPage')->name('client.error');
 
 Route::group(['middleware' => ['auth:contact', 'locale', 'check_client_existence','domain_db'], 'prefix' => 'client', 'as' => 'client.'], function () {