diff --git a/.github/workflows/psalm.yml b/.github/workflows/psalm.yml
new file mode 100644
index 0000000..9b08a74
--- /dev/null
+++ b/.github/workflows/psalm.yml
@@ -0,0 +1,25 @@
+name: Psalm
+
+permissions:
+  contents: read
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  run:
+    name: Run Psalm
+    runs-on: 'ubuntu-latest'
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Setup PHP
+        uses: ./.github/actions/setup-php
+
+      - name: Install Psalm
+        run: composer require --dev vimeo/psalm:6.15.1
+
+      - name: Run Psalm
+        run: ./vendor/bin/psalm --no-cache
diff --git a/psalm.xml b/psalm.xml
new file mode 100644
index 0000000..eb6a1e5
--- /dev/null
+++ b/psalm.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0"?>
+<psalm
+    errorLevel="7"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+    findUnusedBaselineEntry="true"
+    findUnusedCode="false"
+    ensureOverrideAttribute="false"
+>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+</psalm>
diff --git a/src/Supporting/FileMakerRelation.php b/src/Supporting/FileMakerRelation.php
index 140d810..02f1295 100644
--- a/src/Supporting/FileMakerRelation.php
+++ b/src/Supporting/FileMakerRelation.php
@@ -11,6 +11,7 @@
  * and you shouldn't call the constructor of this class.
  *
  * @package INTER-Mediator\FileMakerServer\RESTAPI
+ * @implements Iterator<int, mixed>
  * @link https://github.com/msyk/FMDataAPI GitHub Repository
  * @property string $fieldName The field value named as the property name accessed via __get().
  * @property FileMakerRelation $portalName A FileMakerRelation object associated with the property name accessed via __get().