diff --git a/composer.json b/composer.json
index efa6f993b..216152820 100644
--- a/composer.json
+++ b/composer.json
@@ -56,6 +56,7 @@
     "symfony/finder": "^6.3.0",
     "symfony/http-foundation": "^6.3.0",
     "symfony/mime": "^6.3.0",
+    "symfony/polyfill-php83": "^1.28",
     "symfony/process": "^6.3.0",
     "symfony/property-access": "^6.3.0",
     "symfony/property-info": "^6.3.0",
diff --git a/packages/graphql/README.md b/packages/graphql/README.md
index 1d8d1e6ea..f993c1cc8 100644
--- a/packages/graphql/README.md
+++ b/packages/graphql/README.md
@@ -62,6 +62,31 @@ Probably the most powerful directive to provide sort (`order by` conditions) for
 
 [//]: # (end: ac98e04e18d99ce0a6af07947adce086ad2450bda152abe31548ebe09831ec9a)
 
+# Scalars
+
+> [!IMPORTANT]
+>
+> You should register the Scalar before use, it can be done via [`AstManipulator`](./src/Utils/AstManipulator.php) (useful while AST manipulation), [`TypeRegistry`](https://lighthouse-php.com/master/digging-deeper/adding-types-programmatically.html#using-the-typeregistry), or as a custom scalar inside the Schema:
+>
+> ```graphql
+> scalar JsonString
+> @scalar(
+>     class: "LastDragon_ru\\LaraASP\\GraphQL\\Scalars\\JsonString"
+> )
+> ```
+
+[include:document-list]: ./docs/Scalars
+[//]: # (start: e3795f388ca164b6568d7e4b8d642c7a6ad049711bb0777e6b09e9b5b19e1e11)
+[//]: # (warning: Generated automatically. Do not edit.)
+
+## `JsonString`
+
+Represents [JSON](https://json.org) string.
+
+[Read more](<docs/Scalars/JsonString.md>).
+
+[//]: # (end: e3795f388ca164b6568d7e4b8d642c7a6ad049711bb0777e6b09e9b5b19e1e11)
+
 # Scout
 
 [Scout](https://laravel.com/docs/scout) is also supported 🤩. By default `@searchBy`/`@sortBy` will convert nested/related properties into dot string: eg `{user: {name: asc}}` will be converted into `user.name`. You can redefine this behavior by [`FieldResolver`](./src/Builder/Contracts/Scout/FieldResolver.php):
diff --git a/packages/graphql/composer.json b/packages/graphql/composer.json
index bc42e1336..c744f91b2 100644
--- a/packages/graphql/composer.json
+++ b/packages/graphql/composer.json
@@ -25,7 +25,8 @@
     "nuwave/lighthouse": "^6.5.0",
     "lastdragon-ru/lara-asp-core": "self.version",
     "lastdragon-ru/lara-asp-eloquent": "self.version",
-    "lastdragon-ru/lara-asp-graphql-printer": "self.version"
+    "lastdragon-ru/lara-asp-graphql-printer": "self.version",
+    "symfony/polyfill-php83": "^1.28"
   },
   "require-dev": {
     "ext-pdo_sqlite": "*",
diff --git a/packages/graphql/docs/Scalars/JsonString.md b/packages/graphql/docs/Scalars/JsonString.md
new file mode 100644
index 000000000..af4c2dd35
--- /dev/null
+++ b/packages/graphql/docs/Scalars/JsonString.md
@@ -0,0 +1,13 @@
+# `JsonString`
+
+Represents [JSON](https://json.org) string.
+
+Please note that the scalar doesn't encode/decode value to/from JSON, it just contains a valid JSON string. If you want automatically convert value to/from JSON, you can use the `JSON` type from [`mll-lab/graphql-php-scalars`](https://github.com/mll-lab/graphql-php-scalars) package. If you need something more typesafe, consider using [`Serializer`][pkg:serializer].
+
+[include:file]: ../../../../docs/shared/Links.md
+[//]: # (start: a170145c7adc0561ead408b0ea3a4b46e2e8f45ebc2744984ceb8c1b49822cd1)
+[//]: # (warning: Generated automatically. Do not edit.)
+
+[pkg:serializer]:      https://github.com/LastDragon-ru/lara-asp/tree/main/packages/serializer
+
+[//]: # (end: a170145c7adc0561ead408b0ea3a4b46e2e8f45ebc2744984ceb8c1b49822cd1)
diff --git a/packages/graphql/src/Scalars/JsonString.php b/packages/graphql/src/Scalars/JsonString.php
new file mode 100644
index 000000000..e08125ac2
--- /dev/null
+++ b/packages/graphql/src/Scalars/JsonString.php
@@ -0,0 +1,96 @@
+<?php declare(strict_types = 1);
+
+namespace LastDragon_ru\LaraASP\GraphQL\Scalars;
+
+use Exception;
+use GraphQL\Error\Error;
+use GraphQL\Error\InvariantViolation;
+use GraphQL\Language\AST\Node;
+use GraphQL\Language\AST\NodeKind;
+use GraphQL\Language\AST\StringValueNode;
+use GraphQL\Language\AST\TypeDefinitionNode;
+use GraphQL\Type\Definition\StringType;
+use GraphQL\Type\Definition\Type;
+use GraphQL\Utils\Utils;
+use LastDragon_ru\LaraASP\GraphQL\Builder\BuilderInfo;
+use LastDragon_ru\LaraASP\GraphQL\Builder\Contracts\TypeDefinition;
+use LastDragon_ru\LaraASP\GraphQL\Builder\Contracts\TypeSource;
+use LastDragon_ru\LaraASP\GraphQL\Builder\Manipulator;
+
+use function is_string;
+use function json_validate;
+use function sprintf;
+
+class JsonString extends StringType implements TypeDefinition {
+    public string  $name        = 'JsonString';
+    public ?string $description = 'Represents JSON string.';
+
+    // <editor-fold desc="ScalarType">
+    // =========================================================================
+    public function serialize(mixed $value): string {
+        if ($value instanceof JsonStringable) {
+            $value = (string) $value;
+        } else {
+            $value = $this->validate($value, InvariantViolation::class);
+        }
+
+        return $value;
+    }
+
+    public function parseValue(mixed $value): string {
+        return $this->validate($value, Error::class);
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function parseLiteral(Node $valueNode, array $variables = null): string {
+        if (!($valueNode instanceof StringValueNode)) {
+            throw new Error(
+                sprintf(
+                    'The `%s` value expected, `%s` given.',
+                    NodeKind::STRING,
+                    $valueNode->kind,
+                ),
+            );
+        }
+
+        return $this->parseValue($valueNode->value);
+    }
+
+    /**
+     * @param class-string<Exception> $error
+     *
+     * @phpstan-assert string         $value
+     */
+    protected function validate(mixed $value, string $error): string {
+        if (is_string($value) && json_validate($value)) {
+            // ok
+        } else {
+            throw new $error(
+                sprintf(
+                    'The valid JSON string expected, `%s` given.',
+                    Utils::printSafe($value),
+                ),
+            );
+        }
+
+        return $value;
+    }
+    // </editor-fold>
+
+    // <editor-fold desc="TypeDefinition">
+    // =========================================================================
+    public function getTypeName(Manipulator $manipulator, BuilderInfo $builder, TypeSource $source): string {
+        return $this->name();
+    }
+
+    public function getTypeDefinition(
+        Manipulator $manipulator,
+        string $name,
+        TypeSource $source,
+    ): TypeDefinitionNode|Type|null {
+        return $this;
+    }
+    // </editor-fold>
+}
diff --git a/packages/graphql/src/Scalars/JsonStringTest.php b/packages/graphql/src/Scalars/JsonStringTest.php
new file mode 100644
index 000000000..7d83da9ef
--- /dev/null
+++ b/packages/graphql/src/Scalars/JsonStringTest.php
@@ -0,0 +1,147 @@
+<?php declare(strict_types = 1);
+
+namespace LastDragon_ru\LaraASP\GraphQL\Scalars;
+
+use Exception;
+use GraphQL\Error\Error;
+use GraphQL\Error\InvariantViolation;
+use GraphQL\Language\AST\IntValueNode;
+use GraphQL\Language\AST\Node;
+use GraphQL\Language\AST\StringValueNode;
+use GraphQL\Language\AST\ValueNode;
+use LastDragon_ru\LaraASP\GraphQL\Testing\Package\TestCase;
+use PHPUnit\Framework\Attributes\CoversClass;
+
+/**
+ * @internal
+ */
+#[CoversClass(JsonString::class)]
+class JsonStringTest extends TestCase {
+    // <editor-fold desc="Tests">
+    // =========================================================================
+    /**
+     * @dataProvider dataProviderSerialize
+     */
+    public function testSerialize(?Exception $expected, mixed $value): void {
+        if ($expected instanceof Exception) {
+            self::expectExceptionObject($expected);
+        }
+
+        $scalar = new JsonString();
+        $actual = $scalar->serialize($value);
+
+        if ($value instanceof JsonStringable) {
+            self::assertEquals((string) $value, $actual);
+        } else {
+            self::assertEquals($value, $actual);
+        }
+    }
+
+    /**
+     * @dataProvider dataProviderParseValue
+     */
+    public function testParseValue(?Exception $expected, mixed $value): void {
+        if ($expected instanceof Exception) {
+            self::expectExceptionObject($expected);
+        }
+
+        $scalar = new JsonString();
+        $actual = $scalar->parseValue($value);
+
+        self::assertIsString($value);
+        self::assertEquals($value, $actual);
+    }
+
+    /**
+     * @dataProvider dataProviderParseLiteral
+     */
+    public function testParseLiteral(?Exception $expected, Node&ValueNode $value): void {
+        if ($expected instanceof Exception) {
+            self::expectExceptionObject($expected);
+        }
+
+        $scalar = new JsonString();
+        $actual = $scalar->parseLiteral($value);
+
+        self::assertInstanceOf(StringValueNode::class, $value);
+        self::assertEquals($value->value, $actual);
+    }
+    // </editor-fold>
+
+    // <editor-fold desc="DataProviders">
+    // =========================================================================
+    /**
+     * @return array<string, array{?Exception, mixed}>
+     */
+    public static function dataProviderSerialize(): array {
+        return [
+            'not a string'                => [
+                new InvariantViolation('The valid JSON string expected, `123` given.'),
+                123,
+            ],
+            'string but not a valid json' => [
+                new InvariantViolation('The valid JSON string expected, `"invalid json"` given.'),
+                'invalid json',
+            ],
+            'string and a valid json'     => [
+                null,
+                '{"a": 123, "b": {"c": 45}}',
+            ],
+            JsonStringable::class         => [
+                null,
+                new class('{"a": 123, "b": {"c": 45}}') implements JsonStringable {
+                    public function __construct(
+                        private readonly string $json,
+                    ) {
+                        // empty
+                    }
+
+                    public function __toString(): string {
+                        return $this->json;
+                    }
+                },
+            ],
+        ];
+    }
+
+    /**
+     * @return array<string, array{?Exception, mixed}>
+     */
+    public static function dataProviderParseValue(): array {
+        return [
+            'not a string'                => [
+                new Error('The valid JSON string expected, `123` given.'),
+                123,
+            ],
+            'string but not a valid json' => [
+                new Error('The valid JSON string expected, `"invalid json"` given.'),
+                'invalid json',
+            ],
+            'string and a valid json'     => [
+                null,
+                '{"a": 123, "b": {"c": 45}}',
+            ],
+        ];
+    }
+
+    /**
+     * @return array<string, array{?Exception, Node&ValueNode}>
+     */
+    public static function dataProviderParseLiteral(): array {
+        return [
+            'not a string'                => [
+                new Error('The `StringValue` value expected, `IntValue` given.'),
+                new IntValueNode(['value' => '123']),
+            ],
+            'string but not a valid json' => [
+                new Error('The valid JSON string expected, `"invalid json"` given.'),
+                new StringValueNode(['value' => 'invalid json']),
+            ],
+            'string and a valid json'     => [
+                null,
+                new StringValueNode(['value' => '{"a": 123, "b": {"c": 45}}']),
+            ],
+        ];
+    }
+    // </editor-fold>
+}
diff --git a/packages/graphql/src/Scalars/JsonStringable.php b/packages/graphql/src/Scalars/JsonStringable.php
new file mode 100644
index 000000000..43e7e564a
--- /dev/null
+++ b/packages/graphql/src/Scalars/JsonStringable.php
@@ -0,0 +1,13 @@
+<?php declare(strict_types = 1);
+
+namespace LastDragon_ru\LaraASP\GraphQL\Scalars;
+
+use Stringable;
+
+/**
+ * Marks that string representation of the class is already a valid JSON string,
+ * so validation can be omitted.
+ */
+interface JsonStringable extends Stringable {
+    // empty
+}