diff --git a/.github/workflows/rector.yml b/.github/workflows/rector.yml
new file mode 100644
index 0000000000..af4e6fe012
--- /dev/null
+++ b/.github/workflows/rector.yml
@@ -0,0 +1,88 @@
+# SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+# SPDX-License-Identifier: MIT
+
+name: Rector
+
+on:
+  pull_request:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: rector-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  changes:
+    runs-on: ubuntu-latest-low
+    permissions:
+      contents: read
+      pull-requests: read
+
+    outputs:
+      src: ${{ steps.changes.outputs.src}}
+
+    steps:
+      - uses: dorny/paths-filter@ceb8a2b8f2d89434be7ff52d3de7ec3738c5cc9d # v4.0.3
+        id: changes
+        continue-on-error: true
+        with:
+          filters: |
+            src:
+              - '.github/workflows/**'
+              - 'appinfo/**'
+              - 'lib/**'
+              - 'tests/**'
+              - 'vendor-bin/**'
+              - 'composer.json'
+              - 'composer.lock'
+              - 'rector.php'
+              - '**.php'
+
+  strict:
+    runs-on: ubuntu-latest
+
+    needs: changes
+    if: ${{ needs.changes.outputs.src != 'false' && github.event_name != 'push' && github.repository_owner != 'nextcloud-gmbh' }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+          submodules: true
+
+      - name: Set up php
+        uses: shivammathur/setup-php@f3e473d116dcccaddc5834248c87452386958240 # 2.37.2
+        with:
+          php-version: 8.2
+          extensions: bz2, ctype, curl, dom, fileinfo, gd, iconv, intl, json, libxml, mbstring, openssl, pcntl, posix, session, simplexml, xmlreader, xmlwriter, zip, zlib, sqlite, pdo_sqlite
+          coverage: none
+          ini-file: development
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Install dependencies
+        run: composer i
+
+      - name: Rector
+        run: composer run rector:check
+
+      - name: Show changes
+        if: always()
+        run: git diff --exit-code
+
+  summary:
+    permissions:
+      contents: none
+    runs-on: ubuntu-latest-low
+    needs: [changes, strict]
+
+    if: always()
+
+    name: rector-summary
+
+    steps:
+      - name: Summary status
+        run: if ${{ needs.changes.outputs.src != 'false' && needs.strict.result != 'success' }}; then exit 1; fi
diff --git a/lib/Activity/ActivityManager.php b/lib/Activity/ActivityManager.php
index 452b98591d..ec9dc6b4bd 100644
--- a/lib/Activity/ActivityManager.php
+++ b/lib/Activity/ActivityManager.php
@@ -91,9 +91,7 @@ public function __construct(
 	 * @psalm-param string|null $author
 	 */
 	public function triggerEvent(string $objectType, Row2|Table|View|Column $object, string $subject, array|string|null $additionalParams = [], array|string|null $author = null) {
-		if ($author === null) {
-			$author = $this->userId;
-		}
+		$author ??= $this->userId;
 
 		try {
 			$event = $this->createEvent($objectType, $object, $subject, $additionalParams, $author);
diff --git a/lib/Db/ContextMapper.php b/lib/Db/ContextMapper.php
index 3b677afc64..0da199335e 100644
--- a/lib/Db/ContextMapper.php
+++ b/lib/Db/ContextMapper.php
@@ -103,9 +103,7 @@ protected function formatResultRows(array $rows, ?string $userId) {
 				'display_mode_default' => (int)$item['display_mode_default'],
 			];
 			if ($userId !== null) {
-				if ($item['display_mode'] === null) {
-					$item['display_mode'] = $item['display_mode_default'];
-				}
+				$item['display_mode'] ??= $item['display_mode_default'];
 				$carry[$item['share_id']]['display_mode'] = (int)$item['display_mode'];
 			}
 			return $carry;
@@ -130,9 +128,7 @@ protected function formatResultRows(array $rows, ?string $userId) {
 				// empty Context
 				return $carry;
 			}
-			if (!isset($carry[$item['page_id']])) {
-				$carry[$item['page_id']] = ['content' => []];
-			}
+			$carry[$item['page_id']] ??= ['content' => []];
 			$carry[$item['page_id']]['id'] = (int)$item['page_id'];
 			$carry[$item['page_id']]['page_type'] = $item['page_type'];
 			if ($item['node_rel_id'] !== null) {
diff --git a/lib/Db/Row2Mapper.php b/lib/Db/Row2Mapper.php
index b0cfa89d9a..4e6478cb17 100644
--- a/lib/Db/Row2Mapper.php
+++ b/lib/Db/Row2Mapper.php
@@ -692,9 +692,7 @@ private function parseEntities(IResult $result, array $sleeves): array {
 
 			$column = $this->columnMapper->find($rowData['column_id']);
 			$columnType = $column->getType();
-			if (!isset($cellMapperCache[$columnType])) {
-				$cellMapperCache[$columnType] = $this->getCellMapperFromType($columnType);
-			}
+			$cellMapperCache[$columnType] ??= $this->getCellMapperFromType($columnType);
 			$value = $cellMapperCache[$columnType]->formatRowData($column, $rowData);
 			$compositeKey = (string)$rowData['row_id'] . ',' . (string)$rowData['column_id'];
 			if ($cellMapperCache[$columnType]->hasMultipleValues()) {
diff --git a/lib/Migration/Version2020Date20260513185340.php b/lib/Migration/Version2020Date20260513185340.php
index 067989d001..6e91736462 100644
--- a/lib/Migration/Version2020Date20260513185340.php
+++ b/lib/Migration/Version2020Date20260513185340.php
@@ -74,9 +74,7 @@ private function applyColumnOptionsUpdateIfNecessary(IQueryBuilder $query, int $
 		}
 
 		foreach ($selectionOptions as &$selectionOption) {
-			if (!isset($selectionOption['uuid'])) {
-				$selectionOption['uuid'] = Uuid::v7()->toRfc4122();
-			}
+			$selectionOption['uuid'] ??= Uuid::v7()->toRfc4122();
 		}
 
 		$updatedSelectionOptions = json_encode($selectionOptions);
diff --git a/lib/Migration/Version2202Date20260825184226.php b/lib/Migration/Version2202Date20260825184226.php
index f42aec3443..7cc99b0343 100644
--- a/lib/Migration/Version2202Date20260825184226.php
+++ b/lib/Migration/Version2202Date20260825184226.php
@@ -88,9 +88,7 @@ private function applyColumnOptionsUpdateIfNecessary(IQueryBuilder $query, int $
 		}
 
 		foreach ($selectionOptions as &$selectionOption) {
-			if (!isset($selectionOption['uuid'])) {
-				$selectionOption['uuid'] = Uuid::v7()->toRfc4122();
-			}
+			$selectionOption['uuid'] ??= Uuid::v7()->toRfc4122();
 
 		}
 		unset($selectionOption);
diff --git a/lib/Service/ColumnService.php b/lib/Service/ColumnService.php
index 52a84b03c1..47c88240e1 100644
--- a/lib/Service/ColumnService.php
+++ b/lib/Service/ColumnService.php
@@ -614,9 +614,7 @@ public function delete(int $id, bool $skipRowCleanup = false, ?string $userId =
 	public function findOrCreateColumnsByTitleForTableAsArray(?int $tableId, ?int $viewId, array $titles, array $dataTypes, ?string $userId, bool $createUnknownColumns, int &$countCreatedColumns, int &$countMatchingColumns): array {
 		$result = [];
 
-		if ($userId === null) {
-			$userId = $this->userId;
-		}
+		$userId ??= $this->userId;
 		if ($viewId) {
 			$allColumns = $this->findAllByView($viewId, $userId);
 		} elseif ($tableId) {
@@ -638,10 +636,7 @@ public function findOrCreateColumnsByTitleForTableAsArray(?int $tableId, ?int $v
 				}
 				$result[$i] = '';
 			}
-			// if there are no columns at all
-			if (!isset($result[$i])) {
-				$result[$i] = '';
-			}
+			$result[$i] ??= '';
 			// if column was not found
 			if ($result[$i] === '' && $createUnknownColumns && $dataTypes[$i]['type'] !== Column::TYPE_META_ID) {
 				$description = $this->l->t('This column was automatically created by the import service.');
diff --git a/lib/Service/PermissionsService.php b/lib/Service/PermissionsService.php
index d75479c0d0..dc68798e23 100644
--- a/lib/Service/PermissionsService.php
+++ b/lib/Service/PermissionsService.php
@@ -64,9 +64,7 @@ public function __construct(
 	 * @throws InternalError
 	 */
 	public function preCheckUserId(?string $userId = null, bool $canBeEmpty = true): string {
-		if ($userId === null) {
-			$userId = $this->userId;
-		}
+		$userId ??= $this->userId;
 
 		if ($userId === null) {
 			$e = new \Exception();
diff --git a/lib/Service/RelationService.php b/lib/Service/RelationService.php
index 5928e13727..6d0ca9fade 100644
--- a/lib/Service/RelationService.php
+++ b/lib/Service/RelationService.php
@@ -104,9 +104,7 @@ private function groupColumnsByTarget(array $columns): array {
 			}
 
 			$target = sprintf('%s_%s_%s', $settings['relationType'], $settings['targetId'], $settings['labelColumn']);
-			if (!isset($groups[$target])) {
-				$groups[$target] = [];
-			}
+			$groups[$target] ??= [];
 			$groups[$target][] = $column;
 		}
 
diff --git a/lib/Service/RowService.php b/lib/Service/RowService.php
index 95baa53324..d55456b102 100644
--- a/lib/Service/RowService.php
+++ b/lib/Service/RowService.php
@@ -661,9 +661,7 @@ public function updateSet(
 				throw new InternalError(static::class . ' - ' . __FUNCTION__ . ': ' . $e->getMessage());
 			}
 		} else {
-			if ($tableId === null) {
-				$tableId = $item->getTableId();
-			}
+			$tableId ??= $item->getTableId();
 			if ($tableId !== $item->getTableId()) {
 				$e = new \Exception('Row does not belong to table with id ' . $tableId);
 				$this->logger->error($e->getMessage(), ['exception' => $e]);
diff --git a/lib/Service/TableService.php b/lib/Service/TableService.php
index acc7d24fca..5d5b704cbd 100644
--- a/lib/Service/TableService.php
+++ b/lib/Service/TableService.php
@@ -120,9 +120,7 @@ public function findAll(?string $userId = null, bool $skipTableEnhancement = fal
 
 			// clean duplicates
 			foreach ($sharedTables as $sharedTable) {
-				if (!isset($allTables[$sharedTable->getId()])) {
-					$allTables[$sharedTable->getId()] = $sharedTable;
-				}
+				$allTables[$sharedTable->getId()] ??= $sharedTable;
 			}
 		}
 
diff --git a/tests/integration/features/bootstrap/FeatureContext.php b/tests/integration/features/bootstrap/FeatureContext.php
index 7278b1e12d..2677ae91cc 100644
--- a/tests/integration/features/bootstrap/FeatureContext.php
+++ b/tests/integration/features/bootstrap/FeatureContext.php
@@ -2143,9 +2143,7 @@ public function sendRequestFullUrl($verb, $fullUrl, $body = null, array $headers
 	}
 
 	protected function getUserCookieJar($user) {
-		if (!isset($this->cookieJars[$user])) {
-			$this->cookieJars[$user] = new CookieJar();
-		}
+		$this->cookieJars[$user] ??= new CookieJar();
 		return $this->cookieJars[$user];
 	}