diff --git a/source/packages/com_mokosuitebackup/src/Engine/BackupEngine.php b/source/packages/com_mokosuitebackup/src/Engine/BackupEngine.php
index e45aa94..ae99b0c 100644
--- a/source/packages/com_mokosuitebackup/src/Engine/BackupEngine.php
+++ b/source/packages/com_mokosuitebackup/src/Engine/BackupEngine.php
@@ -232,6 +232,11 @@ class BackupEngine
 			$this->log('Archive created: ' . $sizeHuman);
 			$this->log('SHA-256: ' . ($checksum ?: 'N/A'));
 
+			// Verify archive integrity
+			$this->log('Verifying archive integrity...');
+			$this->verifyArchive($archivePath, $profile->backup_type);
+			$this->log('Archive integrity verified');
+
 			// Step 2.5: Wrap with MokoRestore script (if enabled)
 			$includeMokoRestore = (bool) ($profile->include_mokorestore ?? false);
 
@@ -518,6 +523,90 @@ class BackupEngine
 		$zip->close();
 	}
 
+	/**
+	 * Verify that a backup archive can be opened and contains expected entries.
+	 *
+	 * @param   string  $archivePath  Absolute path to the archive file
+	 * @param   string  $backupType   Backup type: full, database, files, differential
+	 *
+	 * @throws  \RuntimeException  If the archive fails verification
+	 */
+	private function verifyArchive(string $archivePath, string $backupType): void
+	{
+		if (!is_file($archivePath)) {
+			throw new \RuntimeException('Archive file does not exist: ' . $archivePath);
+		}
+
+		$extension = strtolower(pathinfo($archivePath, PATHINFO_EXTENSION));
+
+		// Detect tar.gz (pathinfo only returns 'gz')
+		if ($extension === 'gz' && str_ends_with(strtolower($archivePath), '.tar.gz')) {
+			$this->verifyTarGzArchive($archivePath);
+
+			return;
+		}
+
+		// ZIP verification
+		$zip = new \ZipArchive();
+
+		if ($zip->open($archivePath, \ZipArchive::RDONLY) !== true) {
+			throw new \RuntimeException('Archive integrity check failed: cannot open ZIP file');
+		}
+
+		if ($zip->numFiles < 1) {
+			$zip->close();
+			throw new \RuntimeException('Archive integrity check failed: archive contains no files');
+		}
+
+		// Verify database.sql exists when backup includes database
+		if ($backupType !== 'files') {
+			if ($zip->locateName('database.sql') === false) {
+				$zip->close();
+				throw new \RuntimeException('Archive integrity check failed: database.sql missing from archive');
+			}
+		}
+
+		// Spot-check: verify the first entry is readable
+		$firstName = $zip->getNameIndex(0);
+
+		if ($firstName === false) {
+			$zip->close();
+			throw new \RuntimeException('Archive integrity check failed: cannot read first entry');
+		}
+
+		$zip->close();
+	}
+
+	/**
+	 * Verify a tar.gz archive can be opened and iterated.
+	 *
+	 * @param   string  $archivePath  Absolute path to the .tar.gz file
+	 *
+	 * @throws  \RuntimeException  If the archive fails verification
+	 */
+	private function verifyTarGzArchive(string $archivePath): void
+	{
+		try {
+			$phar = new \PharData($archivePath);
+			$count = 0;
+
+			foreach ($phar as $entry) {
+				// Spot-check: verify at least the first entry is accessible
+				$entry->getFilename();
+				$count++;
+				break;
+			}
+
+			if ($count === 0) {
+				throw new \RuntimeException('Archive integrity check failed: tar.gz archive contains no entries');
+			}
+		} catch (\RuntimeException $e) {
+			throw $e;
+		} catch (\Throwable $e) {
+			throw new \RuntimeException('Archive integrity check failed: ' . $e->getMessage());
+		}
+	}
+
 	/**
 	 * Dispatch the onMokoSuiteBackupAfterRun event so plugins (actionlog, etc.) can react.
 	 */
diff --git a/source/packages/com_mokosuitebackup/src/Engine/SteppedBackupEngine.php b/source/packages/com_mokosuitebackup/src/Engine/SteppedBackupEngine.php
index e6a0f36..de44718 100644
--- a/source/packages/com_mokosuitebackup/src/Engine/SteppedBackupEngine.php
+++ b/source/packages/com_mokosuitebackup/src/Engine/SteppedBackupEngine.php
@@ -347,6 +347,11 @@ class SteppedBackupEngine
 
 		$totalSize = file_exists($session->archivePath) ? filesize($session->archivePath) : 0;
 
+		// Verify archive integrity
+		$session->log('Verifying archive integrity...');
+		$this->verifyArchive($session->archivePath, $session->backupType);
+		$session->log('Archive integrity verified');
+
 		// MokoRestore wrapper
 		if ($session->includeMokoRestore) {
 			$session->log('Wrapping with MokoRestore script...');
@@ -449,6 +454,50 @@ class SteppedBackupEngine
 		$this->completeRecord($session, $uploadFailed);
 	}
 
+	/**
+	 * Verify that a backup archive can be opened and contains expected entries.
+	 *
+	 * @param   string  $archivePath  Absolute path to the archive file
+	 * @param   string  $backupType   Backup type: full, database, files, differential
+	 *
+	 * @throws  \RuntimeException  If the archive fails verification
+	 */
+	private function verifyArchive(string $archivePath, string $backupType): void
+	{
+		if (!is_file($archivePath)) {
+			throw new \RuntimeException('Archive file does not exist: ' . $archivePath);
+		}
+
+		$zip = new \ZipArchive();
+
+		if ($zip->open($archivePath, \ZipArchive::RDONLY) !== true) {
+			throw new \RuntimeException('Archive integrity check failed: cannot open ZIP file');
+		}
+
+		if ($zip->numFiles < 1) {
+			$zip->close();
+			throw new \RuntimeException('Archive integrity check failed: archive contains no files');
+		}
+
+		// Verify database.sql exists when backup includes database
+		if ($backupType !== 'files') {
+			if ($zip->locateName('database.sql') === false) {
+				$zip->close();
+				throw new \RuntimeException('Archive integrity check failed: database.sql missing from archive');
+			}
+		}
+
+		// Spot-check: verify the first entry is readable
+		$firstName = $zip->getNameIndex(0);
+
+		if ($firstName === false) {
+			$zip->close();
+			throw new \RuntimeException('Archive integrity check failed: cannot read first entry');
+		}
+
+		$zip->close();
+	}
+
 	/**
 	 * Mark the backup record as complete.
 	 */