diff --git a/src/Package/ContentPackage.php b/src/Package/ContentPackage.php
new file mode 100644
index 0000000..e2c28e2
--- /dev/null
+++ b/src/Package/ContentPackage.php
@@ -0,0 +1,98 @@
+<?php
+/**
+ * Immutable sync package value object.
+ *
+ * @package WPContentSync
+ */
+
+namespace WPContentSync\Package;
+
+final class ContentPackage {
+	public const SCHEMA_VERSION = '1.0';
+
+	/** @var array<string, mixed> */
+	private array $data;
+
+	/**
+	 * @param array<string, mixed> $data Package data.
+	 */
+	private function __construct( array $data ) {
+		$this->data = $data;
+	}
+
+	/**
+	 * @param array<string, mixed> $data Package data.
+	 */
+	public static function fromArray( array $data ): self {
+		return new self(
+			array(
+				'schema_version' => (string) ( $data['schema_version'] ?? self::SCHEMA_VERSION ),
+				'generated_at'   => (string) ( $data['generated_at'] ?? '' ),
+				'source'         => self::arrayValue( $data['source'] ?? array() ),
+				'destination'    => self::arrayValue( $data['destination'] ?? array() ),
+				'manifest'       => self::arrayValue( $data['manifest'] ?? array() ),
+				'records'        => self::arrayValue( $data['records'] ?? array() ),
+				'checksums'      => self::arrayValue( $data['checksums'] ?? array() ),
+			)
+		);
+	}
+
+	public function schemaVersion(): string {
+		return $this->data['schema_version'];
+	}
+
+	public function generatedAt(): string {
+		return $this->data['generated_at'];
+	}
+
+	/**
+	 * @return array<string, mixed>
+	 */
+	public function source(): array {
+		return $this->data['source'];
+	}
+
+	/**
+	 * @return array<string, mixed>
+	 */
+	public function destination(): array {
+		return $this->data['destination'];
+	}
+
+	/**
+	 * @return array<string, mixed>
+	 */
+	public function manifest(): array {
+		return $this->data['manifest'];
+	}
+
+	/**
+	 * @return array<string, mixed>
+	 */
+	public function records(): array {
+		return $this->data['records'];
+	}
+
+	/**
+	 * @return array<string, mixed>
+	 */
+	public function checksums(): array {
+		return $this->data['checksums'];
+	}
+
+	/**
+	 * @return array<string, mixed>
+	 */
+	public function toArray(): array {
+		return $this->data;
+	}
+
+	/**
+	 * @param mixed $value Value to normalize.
+	 *
+	 * @return array<string, mixed>
+	 */
+	private static function arrayValue( $value ): array {
+		return is_array( $value ) ? $value : array();
+	}
+}
diff --git a/tests/Unit/Package/ContentPackageTest.php b/tests/Unit/Package/ContentPackageTest.php
new file mode 100644
index 0000000..dba721c
--- /dev/null
+++ b/tests/Unit/Package/ContentPackageTest.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace WPContentSync\Tests\Unit\Package;
+
+use PHPUnit\Framework\TestCase;
+use WPContentSync\Package\ContentPackage;
+
+class ContentPackageTest extends TestCase {
+	public function test_it_normalizes_package_arrays(): void {
+		$package = ContentPackage::fromArray(
+			array(
+				'schema_version' => '1.0',
+				'generated_at'   => '2026-04-26T20:30:00+00:00',
+				'source'         => array(
+					'site_url' => 'https://example.test',
+					'name'     => 'Example Production',
+				),
+				'destination'    => array(
+					'site_url' => 'https://staging.example.test',
+					'name'     => 'Example Staging',
+				),
+				'manifest'       => array(
+					'posts'             => 1,
+					'terms'             => 0,
+					'media'             => 0,
+					'custom_post_types' => 0,
+				),
+				'records'        => array(
+					'posts'             => array(
+						array(
+							'id'   => 123,
+							'type' => 'post',
+						),
+					),
+					'terms'             => array(),
+					'media'             => array(),
+					'custom_post_types' => array(),
+				),
+				'checksums'      => array(
+					'records' => 'sha256:abc123',
+				),
+			)
+		);
+
+		self::assertSame( '1.0', $package->schemaVersion() );
+		self::assertSame( '2026-04-26T20:30:00+00:00', $package->generatedAt() );
+		self::assertSame( 'https://example.test', $package->source()['site_url'] );
+		self::assertSame( 'https://staging.example.test', $package->destination()['site_url'] );
+		self::assertSame( 1, $package->manifest()['posts'] );
+		self::assertSame( 123, $package->records()['posts'][0]['id'] );
+		self::assertSame( 'sha256:abc123', $package->checksums()['records'] );
+		self::assertSame( $package->toArray(), ContentPackage::fromArray( $package->toArray() )->toArray() );
+	}
+}