diff --git a/potx.drush.inc b/potx.drush.inc
index c833331..9258c0b 100644
--- a/potx.drush.inc
+++ b/potx.drush.inc
@@ -61,6 +61,44 @@ function potx_drush_help($section) {
 }
 
 /**
+ * Find other paths to look for modules, based on the given folder's path.
+ * The returned paths are based on Drupal 8's folder structure, and include:
+ *   /path/to/drupal/core/modules
+ *                  /sites/all/modules
+ *                  /profiles/ * /modules
+ *                  /modules/
+ *
+ * @param string $folder
+ */
+function potx_drush_module_paths($folder) {
+  $folder = realpath($folder);
+  if (substr($folder, -1) != '/') {
+    $folder = $folder . '/';
+  }
+
+  $module_paths = array();
+  $checks = array('/sites/', '/core/', '/profiles/', '/modules/');
+  foreach ($checks as $check) {
+    if (preg_match("!$check!", $folder)) {
+      $parts = explode($check, $folder, 2);
+      $root = $parts[0];
+      $module_paths[] = $root . '/sites/all/modules/';
+      $module_paths[] = $root . '/core/modules/';
+
+      $profile_dirs = glob($root . '/profiles/*', GLOB_ONLYDIR);
+      if (is_array($profile_dirs)) {
+        foreach ($profile_dirs as $profile_dir) {
+          $module_paths[] = $profile_dir . '/modules/';
+        }
+      }
+
+      return array('core' => $root . '/core/', 'modules' => $module_paths);
+    }
+  }
+
+  return array();
+}
+/**
  * Drush command callback.
  */
 function potx_drush_extract($mode = NULL) {
@@ -68,6 +106,7 @@ function potx_drush_extract($mode = NULL) {
   include_once __DIR__ . '/potx.inc';
 
   $files = array();
+  $extra_paths = array();
   $build_mode = POTX_BUILD_SINGLE;
 
   if (!is_null($mode) && in_array($mode, array('core', 'multiple', 'single'))) {
@@ -97,6 +136,7 @@ function potx_drush_extract($mode = NULL) {
   }
   elseif (!empty($folder_option)) {
     $files = _potx_explore_dir($folder_option, '*', $api_option, TRUE);
+    $extra_paths = potx_drush_module_paths($folder_option);
   }
   else {
     // No file list provided so autodiscover files in current directory.
@@ -108,7 +148,7 @@ function potx_drush_extract($mode = NULL) {
     _potx_process_file($file, 0, '_potx_save_string', '_potx_save_version', $api_option);
   }
 
-  potx_finish_processing('_potx_save_string', $api_option);
+  potx_finish_processing('_potx_save_string', $api_option, $extra_paths);
 
   _potx_build_files(POTX_STRING_RUNTIME, $build_mode);
   _potx_build_files(POTX_STRING_INSTALLER, POTX_BUILD_SINGLE, 'installer');
diff --git a/potx.inc b/potx.inc
index 6ee0900..f51238a 100644
--- a/potx.inc
+++ b/potx.inc
@@ -382,11 +382,11 @@ function _potx_process_file($file_path, $strip_prefix = 0, $save_callback = '_po
  * @param string $save_callback
  * @param int $api_version
  */
-function potx_finish_processing($save_callback = '_potx_save_string', $api_version = POTX_API_CURRENT) {
+function potx_finish_processing($save_callback = '_potx_save_string', $api_version = POTX_API_CURRENT, $extra_paths = array()) {
   global $yaml_translation_patterns;
   if ($api_version > POTX_API_7) {
     // Parsing shipped configuration has to happen after processing all schemas.
-    _potx_parse_shipped_configuration($save_callback, $api_version);
+    _potx_parse_shipped_configuration($save_callback, $api_version, $extra_paths);
     // Clear yaml translation patterns, so translation patterns for a module
     // won't be used for extracting translatable strings for another module.
     $yaml_translation_patterns = NULL;
@@ -1984,35 +1984,54 @@ function _potx_load_yaml_translation_patterns($path) {
  */
 function _potx_parse_yaml_file($code, $file_name, $file_path, $save_callback) {
   global $yaml_translation_patterns;
-  global $_potx_config_set;
+  global $_potx_module_metadata;
 
   if (!is_array($yaml_translation_patterns)) {
     _potx_init_yaml_translation_patterns();
   }
 
+  try {
+    $yaml = Yaml::parse($code);
+  } catch (ParseException $e) {
+    watchdog('potx', "YAML parseing error on file @path: @error", array(
+        '@path' => $file_path,
+        '@error' => $e->getMessage(),
+    ));
+
+    return;
+  }
+
   foreach ($yaml_translation_patterns as $pattern => $trans_list) {
     if (fnmatch($pattern, $file_name) || fnmatch('*/' . $pattern, $file_name)) {
-      try {
-        $yaml = Yaml::parse($code);
-        _potx_find_yaml_translatables($yaml, $trans_list, $file_name, $save_callback);
-      } catch (ParseException $e) {
-        watchdog('potx', "YAML parseing error on file @path: @error", array(
-          '@path' => $file_path,
-          '@error' => $e->getMessage(),
-        ));
-      }
+       _potx_find_yaml_translatables($yaml, $trans_list, $file_name, $save_callback);
     }
   }
 
   if (preg_match('~config/schema/[^/]+\.yml$~', $file_name)) {
-    $schema = Yaml::parse($code);
-    foreach ($schema as $key => $element) {
-      _potx_process_config_schema($key, $element);
-    }
+
+    $module_name = basename(dirname(dirname(dirname($file_name))));
+    $_potx_module_metadata[$module_name]['schemas'][] = $file_name;
   }
-  elseif (preg_match('~config/(install|optional)/[^/]+\.yml$~', $file_name)) {
-    $_potx_config_set[] = $file_path;
+  elseif (preg_match('~config/(install|optional)/[^/]+\.yml$~', $file_name, $matches)) {
+    $module_name = basename(dirname(dirname(dirname($file_name))));
+    // Store install and optional configs separately.
+    $_potx_module_metadata[$module_name]['configs-' . $matches[1]][] = $file_name;
   }
+  elseif (preg_match('~[^/]+.info.yml~', $file_name)) {
+    _potx_load_module_metadata($file_name, $yaml);
+  }
+}
+
+/**
+ * Load a module's metadata from its .info.yml file. Drupal 8+.
+ * This metadata is used during dependency resolution.
+ */
+function _potx_load_module_metadata($info_path, $info_yaml) {
+  global $_potx_module_metadata;
+
+  $module_name = substr(basename($info_path), 0, -9);
+  $_potx_module_metadata[$module_name]['dependencies'] = isset($info_yaml['dependencies']) ? $info_yaml['dependencies'] : array();
+  $_potx_module_metadata[$module_name]['version'] = isset($info_yaml['version']) && $info_yaml['version'] != 'VERSION' ? $info_yaml['version'] : NULL;
 }
 
 /**
@@ -2030,6 +2049,11 @@ function _potx_find_yaml_translatables($yaml, $trans_list, $file_name, $save_cal
     $trans_list['keys'] = array_diff($trans_list['keys'], array('%top-level-key'));
   }
 
+  // Don't try to process empty yaml files.
+  if (!is_array($yaml)) {
+    return;
+  }
+
   foreach ($yaml as $key => $value) {
 
     if (in_array($key, $trans_list['keys'], TRUE)) {
@@ -2131,18 +2155,7 @@ function _potx_find_yaml_translatables($yaml, $trans_list, $file_name, $save_cal
  */
 function _potx_process_config_schema($schema_prefix, $schema_data) {
   global $_potx_processed_schema;
-
-  if (!isset($_potx_processed_schema)) {
-    // The initial values for 'translatables' allows a limited support for
-    // extracting translatable strings from contrib projects, until
-    // https://www.drupal.org/node/1933988 gets in.
-    $_potx_processed_schema = array(
-      'translatables' => array('label', 'text', 'date_format'),
-      'types' => array(),
-      'mappings' => array(),
-      'contexts' => array('date_format' => 'PHP date format'),
-    );
-  }
+  global $_potx_module_schema;
 
   // Elements can opt out of translation with a 'translatable: false' key.
   if (isset($schema_data['translatable']) && $schema_data['translatable'] === FALSE) {
@@ -2167,14 +2180,18 @@ function _potx_process_config_schema($schema_prefix, $schema_data) {
 
     if ($type != 'mapping') {
       $_potx_processed_schema['types'][$schema_prefix] = $type;
+      $_potx_module_schema['types'][$schema_prefix] = $type;
     }
 
     $_potx_processed_schema['mappings'][] = $schema_prefix;
+    $_potx_module_schema['mappings'][] = $schema_prefix;
   }
   else {
     if ($type == 'sequence') {
-      _potx_process_config_schema($schema_prefix . '+sequence', $schema_data['sequence'][0]);
+
+      _potx_process_config_schema($schema_prefix . '+sequence', $schema_data['sequence']);
       $_potx_processed_schema['types'][$schema_prefix] = 'sequence';
+      $_potx_module_schema['types'][$schema_prefix] = 'sequence';
     }
     // If the element's type is in the "translatables" list, or it has a
     // 'translatable: true' key, then it is translatable.
@@ -2182,18 +2199,22 @@ function _potx_process_config_schema($schema_prefix, $schema_data) {
             || (isset($schema_data['translatable'])
                 && $schema_data['translatable'] === TRUE)) {
       $_potx_processed_schema['translatables'][] = $schema_prefix;
+      $_potx_module_schema['translatables'][] = $schema_prefix;
 
       // Elements can define a context string, or inherit the context from their
       // defined type.
       if (isset($schema_data['translation context'])) {
         $_potx_processed_schema['contexts'][$schema_prefix] = $schema_data['translation context'];
+        $_potx_module_schema['contexts'][$schema_prefix] = $schema_data['translation context'];
       }
       elseif (isset($_potx_processed_schema['contexts'][$type])) {
         $_potx_processed_schema['contexts'][$schema_prefix] = $_potx_processed_schema['contexts'][$type];
+        $_potx_module_schema['contexts'][$schema_prefix] = $_potx_processed_schema['contexts'][$type];
       }
     }
     else {
       $_potx_processed_schema['types'][$schema_prefix] = $type;
+      $_potx_module_schema['types'][$schema_prefix] = $type;
     }
   }
 }
@@ -2244,8 +2265,6 @@ function _potx_element_has_schema($type) {
  *     block.*
  */
 function _potx_find_matching_schema($name) {
-  global $_potx_processed_schema;
-
   if (_potx_element_has_schema($name)) {
     return $name;
   }
@@ -2273,6 +2292,31 @@ function _potx_find_matching_schema($name) {
 }
 
 /**
+ * Finds the possible schema keys that match with a config element name.
+ *
+ * @param string $name
+ *   Name of the config element.
+ */
+function _potx_find_matching_schema_candidates($name) {
+  $candidates = array($name);
+
+  $replaced = preg_replace('/([^.:]+)([.:*]*)$/', '*\2', $name);
+  if ($replaced != $name) {
+    $candidates[] = $replaced;
+
+    $one_star = preg_replace('/\.([:.*]*)$/', '.*', $replaced);
+    if ($one_star != $replaced) {
+      $candidates[] = $one_star;
+    }
+
+    $candidates = array_merge($candidates, _potx_find_matching_schema_candidates($replaced));
+    $candidates = array_unique($candidates);
+  }
+
+  return $candidates;
+}
+
+/**
  * Replaces variables in configuration name.
  *
  * The configuration name may contain one or more variables to be replaced,
@@ -2355,28 +2399,329 @@ function _potx_replace_variable($value, $data) {
  * @param string $save_callback
  * @param string $api_version
  */
-function _potx_parse_shipped_configuration($save_callback = '_potx_save_string', $api_version = POTX_API_CURRENT) {
-  global $_potx_config_set;
-  if (!is_array($_potx_config_set)) {
+function _potx_parse_shipped_configuration($save_callback = '_potx_save_string', $api_version = POTX_API_CURRENT, $extra_paths = array()) {
+  global $_potx_module_metadata;
+  global $_potx_schema_cache;
+  global $_potx_processed_schema;
+  global $_potx_processed_modules;
+
+  $_potx_schema_cache = array();
+
+  foreach ($_potx_module_metadata as $module_name => $module_metadata) {
+    if (!isset($module_metadata['configs-install']) && !isset($module_metadata['configs-optional'])) {
+      continue;
+    }
+
+    $_potx_processed_modules = array();
+    $_potx_processed_schema = array(
+        'translatables' => array(),
+        'types' => array(),
+        'mappings' => array(),
+        'contexts' => array()
+    );
+
+    _potx_process_module_schemas(array('core'), $extra_paths);
+    if (!isset($_potx_schema_cache['core'])) {
+      $_potx_schema_cache['core'] = $_potx_processed_schema;
+    }
+    _potx_process_module_schemas(array($module_name), $extra_paths);
+    if (!isset($_potx_schema_cache[$module_name])) {
+      $_potx_schema_cache[$module_name] = $_potx_processed_schema;
+    }
+    if (isset($module_metadata['configs-install'])) {
+      foreach ($module_metadata['configs-install'] as $config_path) {
+
+        $module_path = dirname(dirname(dirname($config_path)));
+
+        // Find the schema that matches the config file.
+        $path_info = pathinfo($config_path);
+        $config_name = $path_info['filename'];
+
+        $config_code = file_get_contents($config_path);
+        $parsed_config = Yaml::parse($config_code);
+        unset($config_code);
+
+        // Dependencies defined in a config file itself should not be visible
+        // to other config files. So, make a temp copy here, and revert after
+        // parsing the config file.
+        $temp = $_potx_processed_schema;
+        if (isset($parsed_config['dependencies']['module'])) {
+          _potx_process_module_schemas($parsed_config['dependencies']['module'], $extra_paths);
+        }
+
+        $schema = _potx_find_matching_schema($config_name);
+        _potx_find_shipped_config_translatables($parsed_config, $schema, NULL, NULL, $config_path, $save_callback);
+        $_potx_processed_schema = $temp;
+      }
+    }
+
+    if (isset($module_metadata['configs-optional'])) {
+      // Optional configs are different, since they do not explicitly specify
+      // which module they belong to.
+      foreach ($module_metadata['configs-optional'] as $config_path) {
+
+        $_potx_processed_modules = array();
+        $_potx_processed_schema = array(
+            'translatables' => array(),
+            'types' => array(),
+            'mappings' => array(),
+            'contexts' => array()
+        );
+
+        _potx_process_module_schemas(array('core'), $extra_paths);
+
+        $module_path = dirname(dirname(dirname($config_path)));
+
+        // Find the schema that matches the config file.
+        $path_info = pathinfo($config_path);
+        $config_name = $path_info['filename'];
+
+        $config_code = file_get_contents($config_path);
+        $parsed_config = Yaml::parse($config_code);
+        unset($config_code);
+
+        $match_candidates = _potx_find_matching_schema_candidates($config_name);
+
+        // Search for modules that contain any schema definitions that could possibly match with this config file.
+        $result = db_query("SELECT * FROM {potx_schema_reverse_lookup} WHERE schema_key IN (:match_candidates)", array(':match_candidates' => $match_candidates));
+        $mapped = array();
+        foreach ($result as $record) {
+          $mapped[$record->schema_key] = $record->module_name;
+        }
+
+        foreach ($match_candidates as $candidate) {
+          if (isset($mapped[$candidate])) {
+            $base_module = $mapped[$candidate];
+
+            _potx_process_module_schemas(array($base_module), $extra_paths);
+            if (!isset($_potx_schema_cache[$base_module])) {
+              $_potx_schema_cache[$base_module] = $_potx_processed_schema;
+            }
+
+            break;
+          }
+        }
+
+        if (isset($parsed_config['dependencies']['module'])) {
+          _potx_process_module_schemas($parsed_config['dependencies']['module'], $extra_paths);
+        }
+
+        $schema = _potx_find_matching_schema($config_name);
+        _potx_find_shipped_config_translatables($parsed_config, $schema, NULL, NULL, $config_path, $save_callback);
+      }
+    }
+  }
+}
+
+/**
+ * Recursively process and merge the schemas required for parsing shipped config.
+ * Fetch the schemas from cache, database, or the local filesystem.
+ * Handles module dependencies, and config optional dependencies.
+ *
+ * @param array $extra_paths
+ *   Extra paths to look for modules, if they are not found in the cache or
+ *   database. This is useful when potx is run locally (e.g. drush), and the
+ *   path to a single module is given by the user.
+ */
+function _potx_process_module_schemas($module_list, $extra_paths = array()) {
+  global $_potx_module_metadata;
+  global $_potx_schema_cache;
+  global $_potx_processed_modules;
+
+  // Remove modules that have already been processed.
+  $module_list = array_diff($module_list, $_potx_processed_modules);
+
+  // If a module's schemas is found in the cache, use that. Dependency schemas
+  //  are already merged in the cache.
+  foreach ($module_list as $module_name) {
+    if (isset($_potx_schema_cache[$module_name])) {
+      $_potx_processed_modules[] = $module_name;
+      unset($module_list[array_search($module_name, $module_list)]);
+      _potx_merge_processed_schema($_potx_schema_cache[$module_name]);
+    }
+  }
+
+  if (count($module_list) == 0) {
     return;
   }
 
-  foreach ($_potx_config_set as $config_path) {
-    // Find the schema that matches the config file.
-    $path_info = pathinfo($config_path);
-    $config_name = $path_info['filename'];
-    $schema = _potx_find_matching_schema($config_name);
+  // Mark as processed early, to prevent a loop while traversing dependency graph.
+  $_potx_processed_modules = array_merge($_potx_processed_modules, $module_list);
 
-    if ($schema == '') {
-      // No schema was found matching this config.
-      continue;
+  $dependencies = array();
+
+  // Fetch processed schema for modules found in the database, and remove them from $module_list.
+  $result = db_query("SELECT * FROM {potx_parsed_data} WHERE module_name IN (:module_names)", array(':module_names' => $module_list));
+  foreach ($result as $record) {
+    $record->dependencies = unserialize($record->dependencies);
+
+    // Processed schemas for a module in database do not include dependency schemas.
+    // Merge the list of dependencies for all modules into $dependencies, and fetch them later.
+    if (is_array($record->dependencies)) {
+      $dependencies = array_merge($dependencies, $record->dependencies);
+    }
+    if (_potx_schema_needs_rebuild($record)) {
+      _potx_store_module_schema($record->module_name, $record);
+    }
+    else {
+      $record->parsed_schema = unserialize($record->parsed_schema);
+      _potx_merge_processed_schema($record->parsed_schema);
+    }
+
+    unset($module_list[array_search($record->module_name, $module_list)]);
+  }
+
+  // For remaining modules that are not found in database or cache:
+  foreach ($module_list as $module_name) {
+    // If the module is already found in the local filesystem, merge its dependecy list.
+    if (isset($_potx_module_metadata[$module_name])) {
+      if (!empty($_potx_module_metadata[$module_name]['dependencies'])) {
+        $dependencies = array_merge($dependencies, $_potx_module_metadata[$module_name]['dependencies']);
+      }
+    }
+    else if (!empty($extra_paths)) {
+      // Look for the module and its schemas in the given extra paths.
+      $found = FALSE;
+
+      if ($module_name == 'core') {
+        $module_files = _potx_explore_dir($extra_paths['core'] . 'config/schema/', '*', POTX_API_8);
+        foreach ($module_files as $file_name) {
+          if (preg_match('~config/schema/[^/]+\.yml$~', $file_name)) {
+            $_potx_module_metadata['core']['schemas'][] = $file_name;
+          }
+        }
+
+        $found = TRUE;
+      }
+      else {
+        foreach($extra_paths['modules'] as $path) {
+          $info_path = $path . $module_name . '/' . $module_name . '.info.yml';
+          if (file_exists($info_path)) {
+
+            $code = file_get_contents($info_path);
+            try {
+              $yaml = Yaml::parse($code);
+            } catch (ParseException $e) {
+              watchdog('potx', "YAML parseing error on file @path: @error", array(
+                  '@path' => $file_path,
+                  '@error' => $e->getMessage(),
+              ));
+
+              continue;
+            }
+
+            _potx_load_module_metadata($info_path, $yaml);
+            $dependencies = array_merge($dependencies, $_potx_module_metadata[$module_name]['dependencies']);
+
+            $module_files = _potx_explore_dir($path . $module_name . '/', '*', POTX_API_8);
+            foreach ($module_files as $file_name) {
+
+              if (preg_match('~config/schema/[^/]+\.yml$~', $file_name)) {
+                $_potx_module_metadata[$module_name]['schemas'][] = $file_name;
+              }
+            }
+
+            $found = TRUE;
+            break;
+          }
+        }
+      }
+
+      if (!$found) {
+        $message = t('Module @module not found. Some shipped configuration translatable strings might be missed.', array('@module' => $module_name));
+        potx_status('error', $message);
+      }
+    }
+  }
+
+  $dependencies = array_unique($dependencies);
+  _potx_process_module_schemas($dependencies, $extra_paths);
+
+  foreach ($module_list as $module_name) {
+    if (isset($_potx_module_metadata[$module_name])) {
+      _potx_store_module_schema($module_name);
     }
+  }
+}
+
+/**
+ * Detects if the processed schema stored in the database for a module needs to be rebuilt.
+ * Dev modules are always rebuild, since they have no version information,
+ *  and are constantly updated.
+ */
+function _potx_schema_needs_rebuild($record) {
+  global $_potx_module_metadata;
+
+  // If the module is found in the filesystem, but it's a different version, or a dev version, it needs a rebuild.
+  return isset($_potx_module_metadata[$record->module_name]) &&
+         (!isset($_potx_module_metadata[$record->module_name]['version']) ||
+         ($_potx_module_metadata[$record->module_name]['version'] != $record->module_version));
+}
+
+/**
+ * Merge a module's processed schema with the global schema storage.
+ */
+function _potx_merge_processed_schema($schema) {
+  global $_potx_processed_schema;
 
-    $config_code = file_get_contents($config_path);
-    $parsed_config = Yaml::parse($config_code);
-    unset($config_code);
+  $_potx_processed_schema['translatables'] = array_merge($_potx_processed_schema['translatables'], $schema['translatables']);
+  $_potx_processed_schema['types'] = array_merge($_potx_processed_schema['types'], $schema['types']);
+  $_potx_processed_schema['mappings'] = array_merge($_potx_processed_schema['mappings'], $schema['mappings']);
+  $_potx_processed_schema['contexts'] = array_merge($_potx_processed_schema['contexts'], $schema['contexts']);
+}
+
+/**
+ * Process a module's config schema files, and store them in the database.
+ *
+ * @param string $record
+ *   The database record to update, if the module's schema is already stored in
+ *   the database.
+ */
+function _potx_store_module_schema($module_name, $record = NULL) {
+  global $_potx_module_metadata;
+  global $_potx_module_schema;
+
+  $_potx_module_schema = array(
+      'translatables' => array(),
+      'types' => array(),
+      'mappings' => array(),
+      'contexts' => array(),
+  );
+
+  $query = db_insert('potx_schema_reverse_lookup')->fields(array('schema_key', 'module_name'));
+
+  if (is_array($_potx_module_metadata[$module_name]['schemas'])) {
+    foreach ($_potx_module_metadata[$module_name]['schemas'] as $file_path) {
+      $code = file_get_contents($file_path);
+      $yaml = Yaml::parse($code);
+      foreach ($yaml as $key => $element) {
+        _potx_process_config_schema($key, $element);
+
+        $query->values(array(
+            'schema_key' => $key,
+            'module_name' => $module_name
+        ));
+      }
+    }
+    $query->execute();
+  }
+
+  if ($record == NULL) {
+    $record = new stdClass();
+    $record->module_name = $module_name;
+    if ($module_name != 'core') {
+      $record->module_version = $_potx_module_metadata[$module_name]['version'];
+      $record->dependencies = $_potx_module_metadata[$module_name]['dependencies'];
+    }
+
+    $record->parsed_schema = $_potx_module_schema;
+
+    drupal_write_record('potx_parsed_data', $record);
+  }
+  else {
+    $record->parsed_schema = $_potx_module_schema;
 
-    _potx_find_shipped_config_translatables($parsed_config, $schema, NULL, NULL, $config_path, $save_callback);
+    drupal_write_record('potx_parsed_data', $record, array('pid'));
   }
 }
 
diff --git a/potx.install b/potx.install
index 0cbf947..ab5759f 100644
--- a/potx.install
+++ b/potx.install
@@ -29,3 +29,68 @@ function potx_requirements($phase) {
 
   return $requirements;
 }
+
+/**
+ * Implements hook_schema().
+ */
+function potx_schema() {
+  $schema = array();
+
+  $schema['potx_parsed_data'] = array(
+      'description' => 'Parsed data for modules (Drupal 8+)',
+      'fields' => array(
+          'pid' => array(
+              'description' => 'Parse ID.',
+              'type' => 'serial',
+              'not null' => TRUE,
+          ),
+          'module_name' => array(
+              'description' => 'Module name.',
+              'type' => 'varchar',
+              'length' => '255',
+              'not null' => TRUE,
+          ),
+          'module_version' => array(
+              'description' => 'Module version.',
+              'type' => 'varchar',
+              'length' => '32',
+          ),
+          'dependencies' => array(
+              'description' => 'The module\'s dependencies.',
+              'type' => 'text',
+              'size' => 'medium',
+              'serialize' => TRUE
+          ),
+          'parsed_schema' => array(
+              'description' => 'The module\'s parsed schema.',
+              'type' => 'text',
+              'size' => 'big',
+              'serialize' => TRUE
+          ),
+      ),
+      'primary key' => array('pid'),
+  );
+  $schema['potx_schema_reverse_lookup'] = array(
+      'description' => 'A reverse lookup table for finding modules based on schema key',
+      'fields' => array(
+          'lid' => array(
+              'description' => 'Lookup ID.',
+              'type' => 'serial',
+              'not null' => TRUE,
+          ),
+          'schema_key' => array(
+              'description' => 'The schema key',
+              'type' => 'varchar',
+              'length' => '500'
+          ),
+          'module_name' => array(
+              'description' => 'The array name',
+              'type' => 'varchar',
+              'length' => '500'
+          )
+      ),
+      'primary key' => array('lid')
+  );
+
+  return $schema;
+}
diff --git a/tests/drupal8/config/schema/test.sequences.schema.yml b/tests/drupal8/config/schema/test.sequences.schema.yml
index 5f7ba6c..537c2c9 100644
--- a/tests/drupal8/config/schema/test.sequences.schema.yml
+++ b/tests/drupal8/config/schema/test.sequences.schema.yml
@@ -2,20 +2,20 @@ simple_sequence:
   type: sequence
   label: 'Test sequence'
   sequence:
-    - type: text
-      label: 'Test string in sequence'
+    type: text
+    label: 'Test string in sequence'
 typed_sequence:
   type: sequence
   sequence:
-    - type: simple_mapping
+    type: simple_mapping
 sequence_of_sequence:
   type: sequence
   sequence:
-    - type: sequence
-      sequence:
-        - type: mapping
-          mapping:
-            id:
-              type: integer
-            description:
-              type: text
+    type: sequence
+    sequence:
+      type: mapping
+      mapping:
+        id:
+          type: integer
+        description:
+          type: text
diff --git a/tests/drupal8/config/schema/test.variables.schema.yml b/tests/drupal8/config/schema/test.variables.schema.yml
index 1d2b714..d9fb11f 100644
--- a/tests/drupal8/config/schema/test.variables.schema.yml
+++ b/tests/drupal8/config/schema/test.variables.schema.yml
@@ -16,7 +16,7 @@ variable.plugin.*:
 basic_variable:
   type: sequence
   sequence:
-    - type: variable.plugin.[plugin_id]
+    type: variable.plugin.[plugin_id]
 
 variable.text:
   type: text
@@ -34,7 +34,7 @@ parent_variable.*:
 key_variable:
   type: sequence
   sequence:
-    - type: variable.[%key]
+    type: variable.[%key]
 
 complex_variable:
   type: mapping
diff --git a/tests/drupal8/core/config/schema/core.data_types.schema.yml b/tests/drupal8/core/config/schema/core.data_types.schema.yml
new file mode 100644
index 0000000..79e3f14
--- /dev/null
+++ b/tests/drupal8/core/config/schema/core.data_types.schema.yml
@@ -0,0 +1,782 @@
+# Base types provided by Drupal core.
+
+# Read https://www.drupal.org/node/1905070 for more details about configuration
+# schema, types and type resolution.
+
+# Undefined type used by the system to assign to elements at any level where
+# configuration schema is not defined. Using explicitly has the same effect as
+# not defining schema, so there is no point in doing that.
+undefined:
+  label: 'Undefined'
+  class: '\Drupal\Core\Config\Schema\Undefined'
+
+# Explicit type to use when no data typing is possible. Instead of using this
+# type, we strongly suggest you use configuration structures that can be
+# described with other structural elements of schema, and describe your schema
+# with those elements.
+ignore:
+  label: 'Ignore'
+  class: '\Drupal\Core\Config\Schema\Ignore'
+
+# Basic scalar data types from typed data.
+boolean:
+  label: 'Boolean'
+  class: '\Drupal\Core\TypedData\Plugin\DataType\BooleanData'
+email:
+  label: 'Email'
+  class: '\Drupal\Core\TypedData\Plugin\DataType\Email'
+integer:
+  label: 'Integer'
+  class: '\Drupal\Core\TypedData\Plugin\DataType\IntegerData'
+float:
+  label: 'Float'
+  class: '\Drupal\Core\TypedData\Plugin\DataType\FloatData'
+string:
+  label: 'String'
+  class: '\Drupal\Core\TypedData\Plugin\DataType\StringData'
+uri:
+  label: 'Uri'
+  class: '\Drupal\Core\TypedData\Plugin\DataType\Uri'
+
+# Container data types for lists with known and unknown keys.
+mapping:
+  label: Mapping
+  class: '\Drupal\Core\Config\Schema\Mapping'
+  definition_class: '\Drupal\Core\TypedData\MapDataDefinition'
+sequence:
+  label: Sequence
+  class: '\Drupal\Core\Config\Schema\Sequence'
+  definition_class: '\Drupal\Core\TypedData\ListDataDefinition'
+
+# Simple extended data types:
+
+# Human readable string that must be plain text and editable with a text field.
+label:
+  type: string
+  label: 'Label'
+  translatable: true
+
+# String containing plural variants, separated by EXT.
+plural_label:
+  type: label
+  label: 'Plural variants'
+
+# Internal Drupal path
+path:
+  type: string
+  label: 'Path'
+
+# Human readable string that can contain multiple lines of text or HTML.
+text:
+  type: string
+  label: 'Text'
+  translatable: true
+
+# PHP Date format string that is translatable.
+date_format:
+  type: string
+  label: 'Date format'
+  translatable: true
+  translation context: 'PHP date format'
+
+# HTML color value.
+color_hex:
+  type: string
+  label: 'Color'
+
+# Complex extended data types:
+
+# Root of a configuration object.
+config_object:
+  type: mapping
+  mapping:
+    langcode:
+      type: string
+      label: 'Language code'
+
+# Mail text with subject and body parts.
+mail:
+  type: mapping
+  label: 'Mail'
+  mapping:
+    subject:
+      type: label
+      label: 'Subject'
+    body:
+      type: text
+      label: 'Body'
+
+# Filter with module and status.
+filter:
+  type: mapping
+  label: 'Filter'
+  mapping:
+    id:
+      type: string
+      label: 'ID'
+    provider:
+      type: string
+      label: 'Provider'
+    status:
+      type: boolean
+      label: 'Status'
+    weight:
+      type: integer
+      label: 'Weight'
+    settings:
+      type: filter_settings.[%parent.id]
+
+# System action configuration base.
+action_configuration_default:
+  type: sequence
+  label: 'Action configuration'
+  sequence:
+    type: string
+
+theme_settings:
+  type: config_object
+  mapping:
+    favicon:
+      type: mapping
+      label: 'Shortcut icon settings'
+      mapping:
+        mimetype:
+          type: string
+          label: 'MIME type'
+        path:
+          type: string
+          label: 'Path'
+        url:
+          type: string
+          label: 'URL'
+        use_default:
+          type: boolean
+          label: 'Use the default shortcut icon supplied by the theme'
+    features:
+      type: mapping
+      label: 'Optional features'
+      mapping:
+        comment_user_picture:
+          type: boolean
+          label: 'User pictures in comments'
+        comment_user_verification:
+          type: boolean
+          label: 'User verification status in comments'
+        favicon:
+          type: boolean
+          label: 'Shortcut icon'
+        logo:
+          type: boolean
+          label: 'Logo'
+        name:
+          type: boolean
+          label: 'Site name'
+        node_user_picture:
+          type: boolean
+          label: 'User pictures in posts'
+        slogan:
+          type: boolean
+          label: 'Site slogan'
+    logo:
+      type: mapping
+      label: 'Logo settings'
+      mapping:
+        path:
+          type: string
+          label: 'Logo path'
+        url:
+          type: uri
+          label: 'URL'
+        use_default:
+          type: boolean
+          label: 'Use default'
+    third_party_settings:
+      type: sequence
+      label: 'Third party settings'
+      sequence:
+        type: theme_settings.third_party.[%key]
+
+views_field_bulk_form:
+  type: views_field
+  label: 'Bulk operation'
+  mapping:
+    action_title:
+      type: label
+      label: 'Action title'
+    include_exclude:
+      type: string
+      label: 'Available actions'
+    selected_actions:
+      type: sequence
+      label: 'Available actions'
+      sequence:
+        type: string
+        label: 'Action'
+
+# Array of routes with route_name and route_params keys.
+route:
+  type: mapping
+  label: 'Route'
+  mapping:
+    route_name:
+      type: string
+      label: 'Route Name'
+    route_params:
+      type: sequence
+      label: 'Route Params'
+      sequence:
+        type: string
+        label: 'Param'
+
+# Config dependencies.
+config_dependencies_base:
+  type: mapping
+  mapping:
+    config:
+      type: sequence
+      label: 'Configuration entity dependencies'
+      sequence:
+        type: string
+    content:
+      type: sequence
+      label: 'Content entity dependencies'
+      sequence:
+        type: string
+    module:
+      type: sequence
+      label: 'Module dependencies'
+      sequence:
+        type: string
+    theme:
+      type: sequence
+      label: 'Theme dependencies'
+      sequence:
+        type: string
+
+config_dependencies:
+  type: config_dependencies_base
+  label: 'Configuration dependencies'
+  mapping:
+    enforced:
+      type: config_dependencies_base
+      label: 'Enforced configuration dependencies'
+
+config_entity:
+  type: mapping
+  mapping:
+    uuid:
+      type: string
+      label: 'UUID'
+    langcode:
+      type: string
+      label: 'Language code'
+    status:
+      type: boolean
+      label: 'Status'
+    dependencies:
+      type: config_dependencies
+      label: 'Dependencies'
+    third_party_settings:
+      type: sequence
+      label: 'Third party settings'
+      sequence:
+        type: '[%parent.%parent.%type].third_party.[%key]'
+
+block_settings:
+  type: mapping
+  label: 'Block settings'
+  mapping:
+    id:
+      type: string
+      label: 'ID'
+    label:
+      type: label
+      label: 'Description'
+    label_display:
+      type: string
+      label: 'Display title'
+    cache:
+      type: mapping
+      label: 'Cache settings'
+      mapping:
+        max_age:
+          type: integer
+          label: 'Maximum age'
+    status:
+      type: boolean
+      label: 'Status'
+    info:
+      type: label
+      label: 'Admin info'
+    view_mode:
+      type: string
+      label: 'View mode'
+    provider:
+      type: string
+      label: 'Provider'
+
+condition.plugin:
+  type: mapping
+  label: 'Condition'
+  mapping:
+    id:
+      type: string
+      label: 'ID'
+    negate:
+      type: boolean
+      label: 'Negate'
+    uuid:
+      type: string
+      label: 'UUID'
+    context_mapping:
+      type: sequence
+      label: 'Context assignments'
+      sequence:
+        type: string
+
+display_variant.plugin:
+  type: mapping
+  label: 'Display variant'
+  mapping:
+    id:
+      type: string
+      label: 'ID'
+    label:
+      type: label
+      label: 'Label'
+    weight:
+      type: integer
+      label: 'Weight'
+    uuid:
+      type: string
+      label: 'UUID'
+
+base_entity_reference_field_settings:
+  type: mapping
+  mapping:
+    target_type:
+      type: string
+      label: 'Type of item to reference'
+    target_bundle:
+      type: string
+      label: 'Bundle of item to reference'
+
+field_config_base:
+  type: config_entity
+  mapping:
+    id:
+      type: string
+      label: 'ID'
+    field_name:
+      type: string
+      label: 'Field name'
+    entity_type:
+      type: string
+      label: 'Entity type'
+    bundle:
+      type: string
+      label: 'Bundle'
+    label:
+      type: label
+      label: 'Label'
+    description:
+      type: text
+      label: 'Help text'
+    required:
+      type: boolean
+      label: 'Required field'
+    translatable:
+      type: boolean
+      label: 'Translatable'
+    default_value:
+      type: sequence
+      label: 'Default values'
+      sequence:
+        type: field.value.[%parent.%parent.field_type]
+        label: 'Default value'
+    default_value_callback:
+      type: string
+      label: 'Default value callback'
+    settings:
+      type: field.field_settings.[%parent.field_type]
+    field_type:
+      type: string
+      label: 'Field type'
+
+core.base_field_override.*.*.*:
+  type: field_config_base
+  label: 'Base field bundle override'
+
+core.date_format.*:
+  type: config_entity
+  label: 'Date format'
+  mapping:
+    id:
+      type: string
+      label: 'ID'
+    label:
+      type: label
+      label: 'Label'
+    locked:
+      type: boolean
+      label: 'Locked'
+    pattern:
+      type: date_format
+      label: 'PHP date format'
+
+# Generic field settings schemas.
+
+field.storage_settings.*:
+  type: mapping
+  label: 'Settings'
+
+field.field_settings.*:
+  type: mapping
+  label: 'Settings'
+
+field.value.*:
+  type: mapping
+  label: 'Default value'
+
+# Schema for the configuration of the String field type.
+
+field.storage_settings.string:
+  type: mapping
+  label: 'String settings'
+  mapping:
+    max_length:
+      type: integer
+      label: 'Maximum length'
+    case_sensitive:
+      type: boolean
+      label: 'Case sensitive'
+    is_ascii:
+      type: boolean
+      label: 'Contains US ASCII characters only'
+
+field.field_settings.string:
+  type: mapping
+  label: 'String settings'
+
+field.value.string:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: string
+      label: 'Value'
+
+# Schema for the configuration of the  String (long) field type.
+
+field.storage_settings.string_long:
+  type: mapping
+  label: 'String (long) settings'
+  mapping:
+    case_sensitive:
+      type: boolean
+      label: 'Case sensitive'
+
+field.field_settings.string_long:
+  type: mapping
+  label: 'String (long) settings'
+
+field.value.string_long:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: text
+      label: 'Value'
+
+# Schema for the configuration of the URI field type.
+
+field.storage_settings.uri:
+  type: mapping
+  label: 'URI settings'
+  mapping:
+    max_length:
+      type: integer
+      label: 'Maximum length'
+    case_sensitive:
+      type: boolean
+      label: 'Case sensitive'
+
+field.field_settings.uri:
+  type: mapping
+  label: 'URI settings'
+
+field.value.uri:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: string
+      label: 'Value'
+
+# Schema for the configuration of the Created field type.
+
+field.storage_settings.created:
+  type: mapping
+  label: 'Created timestamp settings'
+
+field.field_settings.created:
+  type: mapping
+  label: 'Created timestamp settings'
+
+field.value.created:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: integer
+      label: 'Value'
+
+# Schema for the configuration of the Changed field type.
+
+field.storage_settings.changed:
+  type: mapping
+  label: 'Changed timestamp settings'
+
+field.field_settings.changed:
+  type: mapping
+  label: 'Changed timestamp settings'
+
+field.value.changed:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: integer
+      label: 'Value'
+
+# Schema for the configuration of the Entity reference field type.
+
+field.storage_settings.entity_reference:
+  type: mapping
+  label: 'Entity reference field storage settings'
+  mapping:
+    target_type:
+      type: string
+      label: 'Type of item to reference'
+
+field.field_settings.entity_reference:
+  type: mapping
+  label: 'Entity reference field settings'
+  mapping:
+    handler:
+      type: string
+      label: 'Reference method'
+    handler_settings:
+      type: entity_reference_selection.[%parent.handler]
+      label: 'Entity reference selection plugin settings'
+
+field.value.entity_reference:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    target_id:
+      type: string
+      label: 'Value'
+    target_uuid:
+      type: string
+      label: 'Target UUID'
+
+# Schema for the configuration of the Boolean field type.
+
+field.field_settings.boolean:
+  label: 'Boolean settings'
+  type: mapping
+  mapping:
+    on_label:
+      type: string
+      label: 'On label'
+    off_label:
+      type: string
+      label: 'Off label'
+
+field.value.boolean:
+  type: mapping
+  mapping:
+    value:
+      type: integer
+      label: 'Value'
+
+# Schema for the configuration of the Email field type.
+
+field.storage_settings.email:
+  type: mapping
+  label: 'Email settings'
+
+field.field_settings.email:
+  type: mapping
+  label: 'Email settings'
+  sequence:
+    type: string
+    label: 'Setting'
+
+field.value.email:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: email
+      label: 'Value'
+
+# Schema for the configuration of the Integer field type.
+
+field.storage_settings.integer:
+  type: mapping
+  label: 'Integer settings'
+  mapping:
+    unsigned:
+      type: boolean
+      label: 'Unsigned'
+    size:
+      type: string
+      label: 'Database storage size'
+
+field.field_settings.integer:
+  type: mapping
+  label: 'Integer'
+  mapping:
+    min:
+      type: integer
+      label: 'Minimum'
+    max:
+      type: integer
+      label: 'Maximum'
+    prefix:
+      type: label
+      label: 'Prefix'
+    suffix:
+      type: label
+      label: 'Suffix'
+
+field.value.integer:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: integer
+      label: 'Value'
+
+# Schema for the configuration of the Decimal field type.
+
+field.storage_settings.decimal:
+  type: mapping
+  label: 'Decimal settings'
+  mapping:
+    precision:
+      type: integer
+      label: 'Precision'
+    scale:
+      type: integer
+      label: 'Scale'
+
+field.field_settings.decimal:
+  type: mapping
+  label: 'Decimal settings'
+  mapping:
+    min:
+      type: float
+      label: 'Minimum'
+    max:
+      type: float
+      label: 'Maximum'
+    prefix:
+      type: label
+      label: 'Prefix'
+    suffix:
+      type: label
+      label: 'Suffix'
+
+field.value.decimal:
+   type: mapping
+   label: 'Default value'
+   mapping:
+     value:
+       type: float
+       label: 'Value'
+
+# Schema for the configuration of the Float field type.
+
+field.storage_settings.float:
+  type: mapping
+  label: 'Float settings'
+
+field.field_settings.float:
+  type: mapping
+  label: 'Float settings'
+  mapping:
+    min:
+      type: float
+      label: 'Minimum'
+    max:
+      type: float
+      label: 'Maximum'
+    prefix:
+      type: label
+      label: 'Prefix'
+    suffix:
+      type: label
+      label: 'Suffix'
+
+field.value.float:
+  type: mapping
+  label: 'Default value'
+  mapping:
+    value:
+      type: float
+      label: 'Value'
+
+# Text with a text format.
+text_format:
+  type: mapping
+  label: 'Text with text format'
+  # We declare the entire mapping of text and text format as translatable. This
+  # causes the entire mapping to be saved to the language overrides of the
+  # configuration. Storing only the (to be formatted) text could result in
+  # security problems in case the text format of the source text is changed.
+  translatable: true
+  mapping:
+    value:
+      type: text
+      label: 'Text'
+      # Mark the actual text as translatable (in addition to the entire mapping
+      # being marked as translatable) so that shipped configuration with
+      # formatted text can participate in the string translation system.
+      translatable: true
+    format:
+      type: string
+      label: 'Text format'
+      # The text format should not be translated as part of the string
+      # translation system, so this is not marked as translatable.
+
+# Schema for the configuration of the Entity reference selection plugins.
+
+entity_reference_selection:
+  type: mapping
+  label: 'Entity reference selection plugin configuration'
+  mapping:
+    target_bundles:
+      type: sequence
+      label: 'types'
+      sequence:
+        type: string
+        label: 'Type'
+    sort:
+      type: mapping
+      label: 'Sort settings'
+      mapping:
+        field:
+          type: string
+          label: 'Sort by'
+        direction:
+          type: string
+          label: 'Sort direction'
+    auto_create:
+      type: boolean
+      label: 'Create referenced entities if they don''t already exist'
+
+entity_reference_selection.*:
+  type: entity_reference_selection
diff --git a/tests/drupal8/drupal8.info.yml b/tests/drupal8/drupal8.info.yml
new file mode 100644
index 0000000..23df0e1
--- /dev/null
+++ b/tests/drupal8/drupal8.info.yml
@@ -0,0 +1,3 @@
+name: 'Drupal 8 Test'
+type: module
+description: 'Test module for Drupal 8 translatable string extraction.'
diff --git a/tests/potx.test b/tests/potx.test
index 87b5eda..c52ca10 100644
--- a/tests/potx.test
+++ b/tests/potx.test
@@ -403,7 +403,7 @@ class PotxTestCase extends DrupalWebTestCase {
 
     $this->buildOutput(POTX_API_8);
 
-    for ($i = 1; $i < 8; $i++) {
+    for ($i = 2; $i < 8; $i++) {
       $this->assertNoMsgID($i . '');
     }