diff --git a/README.md b/README.md
index f77b096..28d88a9 100644
--- a/README.md
+++ b/README.md
@@ -77,6 +77,8 @@ Here's a comprehensive list of all available rules:
 
 21. **ForbidWeakCryptoKeyRule**: Prevents weak cryptographic key sizes in `openssl_pkey_new()` calls. RSA keys must be at least 2048 bits.
 
+22. **ForbidHardcodedCredentialsRule**: Detects hardcoded credentials (passwords, API keys, secrets, tokens) in array definitions. Use environment variables instead.
+
 ## Configuration
 
 You can customize the behavior of these rules by adding configuration to your `phpstan.neon` file. See the [configuration section](#configuration) for more details.
diff --git a/rules.neon b/rules.neon
index ef04548..086b8f6 100644
--- a/rules.neon
+++ b/rules.neon
@@ -22,6 +22,7 @@ rules:
     - Shopware\PhpStan\Rule\ForwardSalesChannelContextToSystemConfigServiceRule
     - Shopware\PhpStan\Rule\ForbidPredictableSaltRule
     - Shopware\PhpStan\Rule\ForbidWeakCryptoKeyRule
+    - Shopware\PhpStan\Rule\ForbidHardcodedCredentialsRule
 
 services:
     -
diff --git a/src/Rule/ForbidHardcodedCredentialsRule.php b/src/Rule/ForbidHardcodedCredentialsRule.php
new file mode 100644
index 0000000..a4fcbaf
--- /dev/null
+++ b/src/Rule/ForbidHardcodedCredentialsRule.php
@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shopware\PhpStan\Rule;
+
+use PhpParser\Node;
+use PhpParser\Node\ArrayItem;
+use PhpParser\Node\Scalar\String_;
+use PHPStan\Analyser\Scope;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleError;
+use PHPStan\Rules\RuleErrorBuilder;
+
+/**
+ * @implements Rule<ArrayItem>
+ */
+class ForbidHardcodedCredentialsRule implements Rule
+{
+    private const SENSITIVE_KEYS = ['password', 'api_key', 'secret', 'token', 'apikey'];
+
+    public function getNodeType(): string
+    {
+        return ArrayItem::class;
+    }
+
+    /**
+     * @return list<RuleError>
+     */
+    public function processNode(Node $node, Scope $scope): array
+    {
+        if (!$node->key instanceof String_) {
+            return [];
+        }
+
+        $keyName = strtolower($node->key->value);
+        $isSensitive = false;
+        foreach (self::SENSITIVE_KEYS as $sensitive) {
+            if (str_contains($keyName, $sensitive)) {
+                $isSensitive = true;
+                break;
+            }
+        }
+
+        if (!$isSensitive) {
+            return [];
+        }
+
+        if (!$node->value instanceof String_) {
+            return [];
+        }
+
+        $value = $node->value->value;
+        if ($value === '' || $value === '0' || str_starts_with($value, '%') || str_contains($value, 'env(')) {
+            return [];
+        }
+
+        return [
+            RuleErrorBuilder::message('Possible hardcoded credentials detected. Use environment variables.')
+                ->identifier('shopware.forbidHardcodedCredentials')
+                ->line($node->getLine())
+                ->build(),
+        ];
+    }
+}
diff --git a/tests/Rule/ForbidHardcodedCredentialsRuleTest.php b/tests/Rule/ForbidHardcodedCredentialsRuleTest.php
new file mode 100644
index 0000000..ee6676f
--- /dev/null
+++ b/tests/Rule/ForbidHardcodedCredentialsRuleTest.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shopware\PhpStan\Tests\Rule;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+use Shopware\PhpStan\Rule\ForbidHardcodedCredentialsRule;
+
+/**
+ * @extends RuleTestCase<ForbidHardcodedCredentialsRule>
+ */
+class ForbidHardcodedCredentialsRuleTest extends RuleTestCase
+{
+    protected function getRule(): Rule
+    {
+        return new ForbidHardcodedCredentialsRule();
+    }
+
+    public function testRule(): void
+    {
+        $this->analyse([__DIR__ . '/fixtures/ForbidHardcodedCredentialsRule/correct-usage.php'], []);
+        $this->analyse([__DIR__ . '/fixtures/ForbidHardcodedCredentialsRule/wrong-usage.php'], [
+            [
+                'Possible hardcoded credentials detected. Use environment variables.',
+                12,
+            ],
+        ]);
+    }
+}
diff --git a/tests/Rule/fixtures/ForbidHardcodedCredentialsRule/correct-usage.php b/tests/Rule/fixtures/ForbidHardcodedCredentialsRule/correct-usage.php
new file mode 100644
index 0000000..4f5d73a
--- /dev/null
+++ b/tests/Rule/fixtures/ForbidHardcodedCredentialsRule/correct-usage.php
@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shopware\PhpStan\Tests\Rule\fixtures\ForbidHardcodedCredentialsRule;
+
+class CorrectUsage
+{
+    public function envVariablePattern(): array
+    {
+        return [
+            'password' => '%env(DATABASE_PASSWORD)%',
+        ];
+    }
+
+    public function envFunctionPattern(): array
+    {
+        return [
+            'secret' => 'env(APP_SECRET)',
+        ];
+    }
+
+    public function emptyValue(): array
+    {
+        return [
+            'api_key' => '',
+        ];
+    }
+
+    public function zeroValue(): array
+    {
+        return [
+            'apikey' => '0',
+        ];
+    }
+
+    public function nullValue(): array
+    {
+        return [
+            'token' => null,
+        ];
+    }
+
+    public function nonSensitiveKey(): array
+    {
+        return [
+            'username' => 'admin',
+        ];
+    }
+}
diff --git a/tests/Rule/fixtures/ForbidHardcodedCredentialsRule/wrong-usage.php b/tests/Rule/fixtures/ForbidHardcodedCredentialsRule/wrong-usage.php
new file mode 100644
index 0000000..5f35b40
--- /dev/null
+++ b/tests/Rule/fixtures/ForbidHardcodedCredentialsRule/wrong-usage.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shopware\PhpStan\Tests\Rule\fixtures\ForbidHardcodedCredentialsRule;
+
+class WrongUsage
+{
+    public function getConfig(): array
+    {
+        return [
+            'password' => 'secret123',
+        ];
+    }
+}