diff --git a/ProcessMaker/Http/Controllers/Api/V1_1/ProcessVariableController.php b/ProcessMaker/Http/Controllers/Api/V1_1/ProcessVariableController.php
index 2b5f462923..1aff342c03 100644
--- a/ProcessMaker/Http/Controllers/Api/V1_1/ProcessVariableController.php
+++ b/ProcessMaker/Http/Controllers/Api/V1_1/ProcessVariableController.php
@@ -236,7 +236,9 @@ public function getProcessesVariables(array $processIds, $excludeSavedSearch, $p
         // and applies filtering for excluded fields.
         $query = DB::table('asset_variables as av')
             ->join('var_finder_variables as vfv', 'av.id', '=', 'vfv.asset_variable_id')
-            ->whereIn('av.process_id', $processIds)
+            ->when($processIds !== [], function ($query) use ($processIds) {
+                $query->whereIn('av.process_id', $processIds);
+            })
             ->groupBy('vfv.field', 'vfv.label')
             ->select([
                 DB::raw('MAX(vfv.id) as id'),
@@ -256,7 +258,7 @@ public function getProcessesVariables(array $processIds, $excludeSavedSearch, $p
             return $this->mergeOnlyAvailableColumns($paginator, $savedSearch, $activeColumns);
         }
 
-        return $query->paginate($perPage, ['*'], 'page', $page);
+        return $paginator;
     }
 
     /**
@@ -288,9 +290,23 @@ private function mergeAvailableColumns(?SavedSearch $savedSearch = null)
         $availableColumns = collect();
 
         if ($savedSearch?->available_columns) {
-            $availableColumns = $savedSearch->available_columns->merge(
-                $savedSearch->getDataColumnsAttribute() ?? collect()
-            );
+            $availableColumns = $savedSearch->available_columns;
+
+            if (
+                $savedSearch->type === SavedSearch::TYPE_COLLECTION
+                || !class_exists(ProcessVariable::class)
+                || !Schema::hasTable('process_variables')
+                || !self::$useVarFinder
+            ) {
+                $availableColumns = $availableColumns->merge(
+                    $savedSearch->getDataColumnsAttribute() ?? collect()
+                );
+            } else {
+                $availableColumns = $availableColumns
+                    ->merge($savedSearch->process_columns)
+                    ->unique('field')
+                    ->values();
+            }
         }
 
         return $availableColumns;
diff --git a/tests/Feature/Api/V1_1/ProcessVariableControllerTest.php b/tests/Feature/Api/V1_1/ProcessVariableControllerTest.php
index 0b013681de..5f8e6f4cd7 100644
--- a/tests/Feature/Api/V1_1/ProcessVariableControllerTest.php
+++ b/tests/Feature/Api/V1_1/ProcessVariableControllerTest.php
@@ -544,4 +544,131 @@ public function test_saved_search_with_no_available_columns(): void
         $this->assertFalse($filteredFields->contains('initiated_at'));
         $this->assertFalse($filteredFields->contains('completed_at'));
     }
+
+    public function test_only_available_with_empty_process_ids_returns_defaults_and_variables(): void
+    {
+        $this->setupCreateUser();
+
+        if (!$this->isVariablesFinderEnabled) {
+            $this->markTestSkipped('VariableFinder is required for this test.');
+        }
+
+        $savedSearch = SavedSearch::factory()->create([
+            'type' => 'request',
+            'meta' => [
+                'icon' => 'bath',
+                'file' => null,
+                'collection_id' => null,
+                'columns' => [],
+            ],
+            'pmql' => '',
+        ]);
+
+        $response = $this->apiCall(
+            'GET',
+            '/api/1.1/processes/variables?processIds=&savedSearchId=' . $savedSearch->id . '&onlyAvailable='
+        );
+
+        $response->assertStatus(200);
+
+        $fields = collect($response->json('data'))->pluck('field');
+
+        $this->assertTrue($fields->contains('case_number'));
+        $this->assertTrue($fields->contains('name'));
+        $this->assertGreaterThan(10, $fields->count());
+    }
+
+    public function test_only_available_first_page_includes_defaults_and_paginated_variables(): void
+    {
+        $this->setupCreateUser();
+
+        if (!$this->isVariablesFinderEnabled) {
+            $this->markTestSkipped('VariableFinder is required for this test.');
+        }
+
+        $savedSearch = SavedSearch::factory()->create([
+            'type' => 'request',
+            'meta' => [
+                'icon' => 'bath',
+                'file' => null,
+                'collection_id' => null,
+                'columns' => [],
+            ],
+            'pmql' => '',
+        ]);
+
+        $response = $this->apiCall(
+            'GET',
+            '/api/1.1/processes/variables?processIds=1&savedSearchId=' . $savedSearch->id . '&onlyAvailable=&page=1&per_page=5'
+        );
+
+        $response->assertStatus(200);
+
+        $fields = collect($response->json('data'))->pluck('field');
+
+        $this->assertTrue($fields->contains('case_number'));
+        $this->assertGreaterThan(5, $fields->count());
+    }
+
+    public function test_second_page_without_only_available_omits_saved_search_defaults(): void
+    {
+        $this->setupCreateUser();
+
+        if (!$this->isVariablesFinderEnabled) {
+            $this->markTestSkipped('VariableFinder is required for this test.');
+        }
+
+        $savedSearch = SavedSearch::factory()->create([
+            'type' => 'request',
+            'meta' => [
+                'icon' => 'bath',
+                'file' => null,
+                'collection_id' => null,
+                'columns' => [],
+            ],
+            'pmql' => '',
+        ]);
+
+        $response = $this->apiCall(
+            'GET',
+            '/api/1.1/processes/variables?processIds=1&savedSearchId=' . $savedSearch->id . '&page=2&per_page=5'
+        );
+
+        $response->assertStatus(200);
+
+        $fields = collect($response->json('data'))->pluck('field');
+
+        $this->assertFalse($fields->contains('case_number'));
+        $this->assertFalse($fields->contains('case_title'));
+        $this->assertGreaterThan(0, $fields->count());
+    }
+
+    public function test_empty_process_ids_returns_variable_finder_rows(): void
+    {
+        $this->setupCreateUser();
+
+        if (!$this->isVariablesFinderEnabled) {
+            $this->markTestSkipped('VariableFinder is required for this test.');
+        }
+
+        $response = $this->apiCall('GET', '/api/1.1/processes/variables?processIds=&page=1&per_page=100');
+
+        $response->assertStatus(200);
+        $this->assertEquals(30, $response->json('meta.total'));
+    }
+
+    public function test_non_only_available_request_returns_single_paginated_page(): void
+    {
+        $this->setupCreateUser();
+
+        if (!$this->isVariablesFinderEnabled) {
+            $this->markTestSkipped('VariableFinder is required for this test.');
+        }
+
+        $response = $this->apiCall('GET', '/api/1.1/processes/variables?processIds=1&page=1&per_page=5');
+
+        $response->assertStatus(200);
+        $this->assertCount(5, $response->json('data'));
+        $this->assertEquals(10, $response->json('meta.total'));
+    }
 }