diff --git a/src/Prefixer.php b/src/Prefixer.php
new file mode 100644
index 0000000..989ad7d
--- /dev/null
+++ b/src/Prefixer.php
@@ -0,0 +1,32 @@
+<?php
+namespace MBBParser;
+
+class Prefixer {
+	public static function add( array &$fields, string $prefix ): void {
+		if ( ! $prefix ) {
+			return;
+		}
+		foreach ( $fields as &$field ) {
+			if ( ! empty( $field['id'] ) && ! str_starts_with( $field['id'], $prefix ) ) {
+				$field['id'] = $prefix . $field['id'];
+			}
+			if ( ! empty( $field['fields'] ) && is_array( $field['fields'] ) ) {
+				self::add( $field['fields'], $prefix );
+			}
+		}
+	}
+
+	public static function remove( array &$fields, string $prefix ): void {
+		if ( ! $prefix ) {
+			return;
+		}
+		foreach ( $fields as &$field ) {
+			if ( ! empty( $field['id'] ) && str_starts_with( $field['id'], $prefix ) ) {
+				$field['id'] = substr( $field['id'], strlen( $prefix ) );
+			}
+			if ( isset( $field['fields'] ) && is_array( $field['fields'] ) ) {
+				self::remove( $field['fields'], $prefix );
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/src/Unparsers/MetaBox.php b/src/Unparsers/MetaBox.php
index 8bea71e..a45229e 100644
--- a/src/Unparsers/MetaBox.php
+++ b/src/Unparsers/MetaBox.php
@@ -1,6 +1,8 @@
 <?php
 namespace MBBParser\Unparsers;
 
+use MBBParser\Prefixer;
+
 /**
  * This class is the inverse of the parser.
  * We convert the parsed data back to the format that can be saved to the database.
@@ -90,6 +92,11 @@ public function to_minimal_format() {
 			unset( $settings[ $key ] );
 		}
 
+		// Strip prefix from field IDs before exporting to JSON (minimal format)
+		if ( ! empty( $settings['fields'] ) && is_array( $settings['fields'] ) ) {
+			Prefixer::remove( $settings['fields'], $settings['prefix'] ?? '' );
+		}
+
 		ksort( $settings );
 
 		return $settings;
@@ -255,22 +262,53 @@ public function unparse_modified() {
 		return $this;
 	}
 
-	public function unparse_meta_box() {
+	/**
+	 * Unparse the meta box.
+	 *
+	 * For fields:
+	 * - Always keep it as a numeric array.
+	 * - Remove prefix from field IDs for the settings, that can be used for export, builder, local JSON.
+	 * - Add prefix to field IDs for parsed meta box, that's ready for registering.
+	 */
+	public function unparse_meta_box(): static {
 		// If not meta box, return
 		if ( $this->detect_post_type() !== 'meta-box' ) {
 			return $this;
 		}
 
+		$prefix = $this->lookup( [ 'prefix', 'settings.prefix' ], '' );
+
+		// If meta box is already parsed, normalize the fields array.
 		if ( isset( $this->meta_box ) && is_array( $this->meta_box ) ) {
 			// Fix: error on earlier versions that saved fields as object
-			$fields                               = array_values( $this->meta_box['fields'] ?? [] );
+			$fields = $this->meta_box['fields'] ?? [];
+			$fields = array_values( $fields );
+
+			// Remove prefix from field IDs for the settings, that can be used for export, builder, local JSON.
+			Prefixer::remove( $fields, $prefix );
+			$this->fields = $fields;
+
+			// Add prefix to field IDs for parsed meta box, that's ready for registering.
+			Prefixer::add( $fields, $prefix );
 			$this->settings['meta_box']['fields'] = $fields;
 
 			return $this;
 		}
 
+		// If meta box is not parsed, normalize the fields array.
+		$fields = $this->fields ?: [];
+		$fields = array_values( $fields );
+
+		// Remove prefix from field IDs for the settings, that can be used for export, builder, local JSON.
+		Prefixer::remove( $fields, $prefix );
+		$this->fields = $fields;
+
 		$meta_box = $this->get_settings();
 
+		// Add prefix to field IDs for parsed meta box, that's ready for registering.
+		Prefixer::add( $fields, $prefix );
+		$meta_box['fields'] = $fields;
+
 		foreach ( $this->get_unneeded_keys() as $key ) {
 			unset( $meta_box[ $key ] );
 		}
@@ -312,7 +350,7 @@ private function unparse_settings_page_tabs(): self {
 
 		$tab_items = [];
 		foreach ( $tabs as $key => $value ) {
-			$id = uniqid( 'tab_' );
+			$id               = uniqid( 'tab_' );
 			$tab_items[ $id ] = compact( 'id', 'key', 'value' );
 		}