diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/FieldMapping.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/FieldMapping.php
index c98cd44be1..dbfda581f4 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/FieldMapping.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/FieldMapping.php
@@ -11,7 +11,7 @@
 
 namespace Alchemy\Phrasea\SearchEngine\Elastic;
 
-abstract class FieldMapping
+class FieldMapping
 {
 
     const DATE_FORMAT_MYSQL = 'yyyy-MM-dd HH:mm:ss';
@@ -47,6 +47,7 @@ abstract class FieldMapping
         self::TYPE_SHORT,
         self::TYPE_BYTE,
         self::TYPE_IP,
+        self::TYPE_OBJECT
     );
 
     /**
@@ -64,6 +65,15 @@ abstract class FieldMapping
      */
     private $indexed = true;
 
+    /**
+     * @var bool
+     */
+    private $enabled = true;
+
+    /**
+     * @var bool
+     */
+    private $raw = false;
 
     /**
      * @param string $name
@@ -77,7 +87,7 @@ abstract class FieldMapping
 
         if (! in_array($type, self::$types)) {
             throw new \InvalidArgumentException(sprintf(
-                'Invalid field mapping type "%s", expected "%s" or Mapping instance.',
+                'Invalid field mapping type "%s", expected "%s"',
                 $type,
                 implode('", "', self::$types)
             ));
@@ -125,10 +135,46 @@ abstract class FieldMapping
         return $this;
     }
 
+    public function enableRawIndexing()
+    {
+        $this->raw = true;
+
+        return $this;
+    }
+
+    /**
+     * @return bool
+     */
+    public function isEnabled()
+    {
+        return $this->enabled;
+    }
+
+    public function enableMapping()
+    {
+        $this->enabled = true;
+    }
+
+    public function disableMapping()
+    {
+        $this->enabled = false;
+    }
+
     /**
      * @return array
      */
-    abstract public function toArray();
+    public function toArray()
+    {
+        return $this->buildArray($this->getProperties());
+    }
+
+    /**
+     * @return array
+     */
+    protected function getProperties()
+    {
+        return [];
+    }
 
     /**
      * Helper function to append custom field properties to generic properties array
@@ -136,11 +182,26 @@ abstract class FieldMapping
      * @param array $fieldProperties
      * @return array
      */
-    protected function buildArray(array $fieldProperties = [])
+    private function buildArray(array $fieldProperties = [])
     {
-        return array_merge([
-            'type' => $this->getType(),
-            'index' => $this->indexed ? 'yes' : 'no'
-        ], $fieldProperties);
+        $baseProperties = [ ];
+
+        if ($this->type !== self::TYPE_OBJECT) {
+            $baseProperties['type'] = $this->type;
+        } else {
+            $baseProperties['properties'] = [];
+        }
+
+        if (! $this->indexed) {
+            $baseProperties['index'] = 'no';
+        } elseif ($this->raw) {
+            $baseProperties['index'] = 'not_analyzed';
+        }
+
+        if (! $this->enabled) {
+            $baseProperties['enabled'] = false;
+        }
+
+        return array_replace($baseProperties, $fieldProperties);
     }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/RecordIndexer.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/RecordIndexer.php
index a938292b22..8054b29793 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/RecordIndexer.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/RecordIndexer.php
@@ -25,6 +25,7 @@ use Alchemy\Phrasea\SearchEngine\Elastic\Indexer\Record\Hydrator\SubDefinitionHy
 use Alchemy\Phrasea\SearchEngine\Elastic\Indexer\Record\Hydrator\ThesaurusHydrator;
 use Alchemy\Phrasea\SearchEngine\Elastic\Indexer\Record\Hydrator\TitleHydrator;
 use Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
+use Alchemy\Phrasea\SearchEngine\Elastic\MappingBuilder;
 use Alchemy\Phrasea\SearchEngine\Elastic\RecordHelper;
 use Alchemy\Phrasea\SearchEngine\Elastic\Structure\Field;
 use Alchemy\Phrasea\SearchEngine\Elastic\Structure\Structure;
@@ -308,7 +309,7 @@ class RecordIndexer
         return array_values($databoxes);
     }
 
-    private function indexFromFetcher(BulkOperation $bulk, Fetcher $fetcher, array &$submited_records)
+    private function indexFromFetcher(BulkOperation $bulk, Fetcher $fetcher, array &$submitted_records)
     {
         $databox = $fetcher->getDatabox();
         $first = true;
@@ -338,9 +339,124 @@ class RecordIndexer
             $params['type'] = self::TYPE_NAME;
             $params['body'] = $record;
 
-            $submited_records[$op_identifier] = $record;
+            $submitted_records[$op_identifier] = $record;
 
             $bulk->index($params, $op_identifier);
         }
     }
+
+
+    public function getMapping()
+    {
+        $mapping = new MappingBuilder();
+
+        // Compound primary key
+        $mapping->addField('record_id', FieldMapping::TYPE_INTEGER);
+        $mapping->addField('databox_id', FieldMapping::TYPE_INTEGER);
+
+        // Database name (still indexed for facets)
+        $mapping->addStringField('databox_name')->disableAnalysis();
+        // Unique collection ID
+        $mapping->addField('base_id', FieldMapping::TYPE_INTEGER);
+        // Useless collection ID (local to databox)
+        $mapping->addField('collection_id', FieldMapping::TYPE_INTEGER)->disableIndexing();
+        // Collection name (still indexed for facets)
+        $mapping->addStringField('collection_name')->disableAnalysis();
+
+        $mapping->addStringField('uuid')->disableIndexing();
+        $mapping->addStringField('sha256')->disableIndexing();
+        $mapping->addStringField('original_name')->disableIndexing();
+        $mapping->addStringField('mime')->disableAnalysis();
+        $mapping->addStringField('type')->disableAnalysis();
+        $mapping->addStringField('record_type')->disableAnalysis();
+
+        $mapping->addDateField('created_on', FieldMapping::DATE_FORMAT_MYSQL_OR_CAPTION);
+        $mapping->addDateField('updated_on', FieldMapping::DATE_FORMAT_MYSQL_OR_CAPTION);
+
+        $mapping->add($this->buildThesaurusPathMapping('concept_path'));
+        $mapping->add($this->buildMetadataTagMapping('metadata_tags'));
+        $mapping->add($this->buildFlagMapping('flags'));
+
+        $mapping->addField('flags_bitfield', FieldMapping::TYPE_INTEGER)->disableIndexing();
+        $mapping->addField('subdefs', FieldMapping::TYPE_OBJECT)->disableMapping();
+        $mapping->addField('title', FieldMapping::TYPE_OBJECT)->disableMapping();
+
+        // Caption mapping
+        $this->buildCaptionMapping($mapping, 'caption', $this->structure->getUnrestrictedFields());
+        $this->buildCaptionMapping($mapping, 'private_caption', $this->structure->getPrivateFields());
+
+        echo var_export($mapping->getMapping()->export()); die();
+    }
+
+    private function buildCaptionMapping(MappingBuilder $parent, $name, array $fields)
+    {
+        $fieldConverter = new Mapping\FieldToFieldMappingConverter();
+        $captionMapping = new Mapping\ComplexFieldMapping($name, FieldMapping::TYPE_OBJECT);
+
+        $captionMapping->useAsPropertyContainer();
+
+        foreach ($fields as $field) {
+            $captionMapping->addChild($fieldConverter->convertField($field, $this->locales));
+        }
+
+        $parent->add($captionMapping);
+
+        $localizedCaptionMapping = new Mapping\StringFieldMapping(sprintf('%s_all', $name));
+        $localizedCaptionMapping
+            ->addLocalizedChildren($this->locales)
+            ->addChild((new Mapping\StringFieldMapping('raw'))->enableRawIndexing());
+
+        $parent->add($localizedCaptionMapping);
+
+        return $captionMapping;
+    }
+
+    private function buildThesaurusPathMapping($name)
+    {
+        $thesaurusMapping = new Mapping\ComplexFieldMapping($name, FieldMapping::TYPE_OBJECT);
+
+        foreach (array_keys($this->structure->getThesaurusEnabledFields()) as $name) {
+            $child = new Mapping\StringFieldMapping($name);
+
+            $child->setAnalyzer('thesaurus_path', 'indexing');
+            $child->setAnalyzer('keyword', 'searching');
+            $child->addChild((new Mapping\StringFieldMapping('raw'))->enableRawIndexing());
+
+            $thesaurusMapping->addChild($thesaurusMapping);
+        }
+
+        return $thesaurusMapping;
+    }
+
+    private function buildMetadataTagMapping($name)
+    {
+        $tagConverter = new Mapping\MetadataTagToFieldMappingConverter();
+        $metadataMapping = new Mapping\ComplexFieldMapping($name, FieldMapping::TYPE_OBJECT);
+
+        $metadataMapping->useAsPropertyContainer();
+
+        foreach ($this->structure->getMetadataTags() as $tag) {
+            $metadataMapping->addChild($tagConverter->convertTag($tag));
+        }
+
+        return $metadataMapping;
+    }
+
+    private function buildFlagMapping($name)
+    {
+        $index = 0;
+        $flagMapping = new Mapping\ComplexFieldMapping($name, FieldMapping::TYPE_OBJECT);
+
+        $flagMapping->useAsPropertyContainer();
+
+        foreach ($this->structure->getAllFlags() as $childName => $_) {
+            if (trim($childName) == '') {
+                $childName = 'flag_' . $index++;
+            }
+
+            $flagMapping->addChild(new FieldMapping($childName, FieldMapping::TYPE_BOOLEAN));
+        }
+
+        return $flagMapping;
+    }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php
index c66f8583ba..a11695cd59 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php
@@ -11,7 +11,9 @@
 
 namespace Alchemy\Phrasea\SearchEngine\Elastic\Indexer;
 
+use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
 use Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
+use Alchemy\Phrasea\SearchEngine\Elastic\MappingBuilder;
 use Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus\Helper;
 use Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus\Navigator;
 use Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus\TermVisitor;
@@ -81,25 +83,27 @@ class TermIndexer
 
     public function getMapping()
     {
-        $mapping = new Mapping();
-        $mapping
-            ->add('raw_value', 'string')->notAnalyzed()
-            ->add('value', 'string')
-                ->analyzer('general_light')
-                ->addMultiField('strict', 'thesaurus_term_strict')
-                ->addLocalizedSubfields($this->locales)
-            ->add('context', 'string')
-                ->analyzer('general_light')
-                ->addMultiField('strict', 'thesaurus_term_strict')
-                ->addLocalizedSubfields($this->locales)
-            ->add('path', 'string')
-                ->analyzer('thesaurus_path', 'indexing')
-                ->analyzer('keyword', 'searching')
-                ->addRawVersion()
-            ->add('lang', 'string')->notAnalyzed()
-            ->add('databox_id', 'integer')
-        ;
+        $mapping = new MappingBuilder();
 
-        return $mapping->export();
+        $mapping->addStringField('raw_value')->disableAnalysis();
+        $mapping->addStringField('value')
+            ->setAnalyzer('general_light')
+            ->addAnalyzedChild('strict', 'thesaurus_term_strict')
+            ->addLocalizedChildren($this->locales);
+
+        $mapping->addStringField('context')
+            ->setAnalyzer('general_light')
+            ->addAnalyzedChild('strict', 'thesaurus_term_strict')
+            ->addLocalizedChildren($this->locales);
+
+        $mapping->addStringField('path')
+            ->setAnalyzer('thesaurus_path', 'indexing')
+            ->setAnalyzer('keyword', 'searching')
+            ->addRawChild();
+
+        $mapping->addStringField('lang')->disableAnalysis();
+        $mapping->addField('databox_id', FieldMapping::TYPE_STRING);
+
+        return $mapping->getMapping()->export();
     }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping.php
index e61f6cf8b7..d25995ce96 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping.php
@@ -11,113 +11,63 @@
 
 namespace Alchemy\Phrasea\SearchEngine\Elastic;
 
-use LogicException;
-use RuntimeException;
-
 class Mapping
 {
 
-    const DATE_FORMAT_MYSQL = 'yyyy-MM-dd HH:mm:ss';
-    const DATE_FORMAT_CAPTION = 'yyyy/MM/dd'; // ES format
-    const DATE_FORMAT_MYSQL_OR_CAPTION = 'yyyy-MM-dd HH:mm:ss||yyyy/MM/dd';
-    const DATE_FORMAT_CAPTION_PHP = 'Y/m/d';  // PHP format
-
-    // Core types
-    const TYPE_STRING  = 'string';
-    const TYPE_BOOLEAN = 'boolean';
-    const TYPE_DATE    = 'date';
-
-    // Number core types
-    const TYPE_FLOAT   = 'float';
-    const TYPE_DOUBLE  = 'double';
-    const TYPE_INTEGER = 'integer';
-    const TYPE_LONG    = 'long';
-    const TYPE_SHORT   = 'short';
-    const TYPE_BYTE    = 'byte';
-    const TYPE_IP      = 'ip';
-
-    // Compound types
-    const TYPE_OBJECT  = 'object';
-
-    private static $types = array(
-        self::TYPE_STRING,
-        self::TYPE_BOOLEAN,
-        self::TYPE_DATE,
-        self::TYPE_FLOAT,
-        self::TYPE_DOUBLE,
-        self::TYPE_INTEGER,
-        self::TYPE_LONG,
-        self::TYPE_SHORT,
-        self::TYPE_BYTE,
-        self::TYPE_IP,
-    );
-
     public static function disabledMapping()
     {
         return (new self())->disable();
     }
 
     /**
-     * @var array
+     * @var FieldMapping[]
      */
     private $fields = array();
 
-    /**
-     * @var string
-     */
-    private $current;
-
     /**
      * @var bool
      */
     private $enabled = true;
 
+    /**
+     * @param FieldMapping $fieldMapping
+     * @return FieldMapping
+     */
+    public function addField(FieldMapping $fieldMapping)
+    {
+        return $this->fields[$fieldMapping->getName()] = $fieldMapping;
+    }
+
     /**
      * @param string $name
-     * @param string|Mapping $type
-     * @return $this
+     * @return bool
+     * @deprecated Use hasField instead
      */
-    public function add($name, $type)
+    public function has($name)
     {
-        if ($type instanceof self) {
-            return $this->addComplexType($name, $type);
-        }
-
-        if (! in_array($type, self::$types)) {
-            throw new RuntimeException(sprintf(
-                'Invalid field mapping type "%s", expected "%s" or Mapping instance.',
-                $type,
-                implode('", "', self::$types)
-            ));
-        }
-
-        return $this->addFieldConfiguration($name, [ 'type' => $type ]);
+        return $this->hasField($name);
     }
 
     /**
-     * @param $name
-     * @param Mapping $typeMapping
-     * @return $this
+     * @param string $name
+     * @return bool
      */
-    public function addComplexType($name, Mapping $typeMapping)
+    public function hasField($name)
     {
-        return $this->addFieldConfiguration($name, [
-            'type' => self::TYPE_OBJECT,
-            'mapping' => $typeMapping
-        ]);
+        return isset($this->fields[$name]);
     }
 
-    /**
-     * @param $name
-     * @param array $configuration
-     * @return $this
-     */
-    private function addFieldConfiguration($name, array $configuration)
+    public function removeField($name)
     {
-        $this->fields[$name] = $configuration;
-        $this->current = $name;
+        if ($this->has($name)) {
+            $field = $this->fields[$name];
 
-        return $this;
+            unset($this->fields[$name]);
+
+            return $field;
+        }
+
+        throw new \InvalidArgumentException('Mapping does not contain field: ' . $name);
     }
 
     /**
@@ -129,14 +79,10 @@ class Mapping
         $mapping['properties'] = array();
 
         foreach ($this->fields as $name => $field) {
-            if ($field['type'] === self::TYPE_OBJECT) {
-                $field = $field['mapping']->export();
-            }
-
-            $mapping['properties'][$name] = $field;
+            $mapping['properties'][$name] = $field->toArray();
         }
 
-        if (!$this->enabled) {
+        if (! $this->enabled) {
             $mapping['enabled'] = false;
         }
 
@@ -154,88 +100,4 @@ class Mapping
 
         return $this;
     }
-
-    public function addRawVersion()
-    {
-        $field = & $this->currentField();
-
-        $field['fields']['raw'] = [
-            'type' => $field['type'],
-            'index' => 'not_analyzed'
-        ];
-
-        return $this;
-    }
-
-    /**
-     * @deprecated
-     */
-    public function addAnalyzedVersion(array $locales)
-    {
-        $this->addMultiField('light', 'general_light');
-
-        return $this->addLocalizedSubfields($locales);
-    }
-
-    public function addLocalizedSubfields(array $locales)
-    {
-        foreach ($locales as $locale) {
-            $this->addMultiField($locale, sprintf('%s_full', $locale));
-        }
-
-        return $this;
-    }
-
-    public function addMultiField($name, $analyzer = null)
-    {
-        $field = &$this->currentField();
-
-        if (isset($field['fields'][$name])) {
-            throw new LogicException(sprintf('There is already a "%s" multi field.', $name));
-        }
-
-        $field['fields'][$name] = array();
-        $field['fields'][$name]['type'] = $field['type'];
-
-        if ($analyzer) {
-            $field['fields'][$name]['analyzer'] = $analyzer;
-        }
-
-        return $this;
-    }
-
-    public function enableTermVectors($recursive = false)
-    {
-        $field = &$this->currentField();
-
-        if ($field['type'] !== self::TYPE_STRING) {
-            throw new LogicException('Only string fields can have term vectors');
-        }
-
-        $field['term_vector'] = 'with_positions_offsets';
-
-        if ($recursive) {
-            if (isset($field['fields'])) {
-                foreach ($field['fields'] as $name => &$options) {
-                    $options['term_vector'] = 'with_positions_offsets';
-                }
-            }
-        }
-
-        return $this;
-    }
-
-    public function has($name)
-    {
-        return isset($this->fields[$name]);
-    }
-
-    protected function &currentField()
-    {
-        if (null === $this->current) {
-            throw new LogicException('You must add a field first');
-        }
-
-        return $this->fields[$this->current];
-    }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/ComplexFieldMapping.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/ComplexFieldMapping.php
index 4c558765a1..1159144650 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/ComplexFieldMapping.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/ComplexFieldMapping.php
@@ -20,12 +20,49 @@ class ComplexFieldMapping extends FieldMapping
      */
     private $children = [];
 
+    private $childKey = 'fields';
+
+    public function useAsPropertyContainer()
+    {
+        $this->childKey = 'properties';
+    }
+
+    public function useAsFieldContainer()
+    {
+        $this->childKey = 'fields';
+    }
+
     /**
      * @param FieldMapping $child
+     * @return FieldMapping
      */
     public function addChild(FieldMapping $child)
     {
-        $this->children[] = $child;
+        if (isset($this->children[$child->getName()])) {
+            throw new \LogicException(sprintf('There is already a "%s" multi field.', $child->getName()));
+        }
+
+        if ($child->getType() !== $this->getType() && $this->getType() !== self::TYPE_OBJECT) {
+            throw new \LogicException('Child field type must match parent type.');
+        }
+
+        return $this->children[$child->getName()] = $child;
+    }
+
+    /**
+     * @return RawFieldMapping
+     */
+    public function addRawChild()
+    {
+        return $this->addChild(new RawFieldMapping($this->getType()));
+    }
+
+    /**
+     * @return bool
+     */
+    public function hasChildren()
+    {
+        return ! empty($this->children);
     }
 
     /**
@@ -39,8 +76,18 @@ class ComplexFieldMapping extends FieldMapping
     /**
      * @return array
      */
-    public function toArray()
+    protected function getProperties()
     {
-        return $this->buildArray([ ]);
+        if (! $this->hasChildren()) {
+            return [];
+        }
+
+        $properties = [ ];
+
+        foreach ($this->children as $name => $child) {
+            $properties[$name] = $child->toArray();
+        }
+
+        return [ $this->childKey => $properties ];
     }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/DateFieldMapping.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/DateFieldMapping.php
index 0a65851f1b..a96ef45f4a 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/DateFieldMapping.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/DateFieldMapping.php
@@ -11,13 +11,11 @@
 
 namespace Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
 
-use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
-
 /**
  * Class DateFieldMapping
  * @package Alchemy\Phrasea\SearchEngine\Elastic\Mapping
  */
-class DateFieldMapping extends FieldMapping
+class DateFieldMapping extends ComplexFieldMapping
 {
     /**
      * @var string
@@ -26,12 +24,11 @@ class DateFieldMapping extends FieldMapping
 
     /**
      * @param string $name
-     * @param string $type
      * @param string $format
      */
-    public function __construct($name, $type, $format)
+    public function __construct($name, $format)
     {
-        parent::__construct($name, $type);
+        parent::__construct($name, self::TYPE_DATE);
 
         $this->format = $format;
     }
@@ -58,8 +55,8 @@ class DateFieldMapping extends FieldMapping
     /**
      * @return array
      */
-    public function toArray()
+    protected function getProperties()
     {
-        return $this->buildArray([ 'format' => $this->format ]);
+        return array_merge([ 'format' => $this->format ], parent::getProperties());
     }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/FieldToFieldMappingConverter.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/FieldToFieldMappingConverter.php
new file mode 100644
index 0000000000..46c28b9cce
--- /dev/null
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/FieldToFieldMappingConverter.php
@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of phrasea-4.0.
+ *
+ * (c) Alchemy <info@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
+
+use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
+use Alchemy\Phrasea\SearchEngine\Elastic\Structure\Field;
+
+class FieldToFieldMappingConverter
+{
+
+    public function convertField(Field $field, array $locales)
+    {
+        if ($field->getType() === FieldMapping::TYPE_DATE) {
+            return new DateFieldMapping($field->getName(), FieldMapping::DATE_FORMAT_CAPTION);
+        }
+
+        if ($field->getType() === FieldMapping::TYPE_STRING) {
+            $fieldMapping = new StringFieldMapping($field->getName());
+
+            if (! $field->isFacet() && ! $field->isSearchable()) {
+                $fieldMapping->disableIndexing();
+            } else {
+                $fieldMapping->addChild((new StringFieldMapping('raw'))->enableRawIndexing());
+                $fieldMapping->addAnalyzedChildren($locales);
+                $fieldMapping->enableTermVectors(true);
+            }
+
+            return $fieldMapping;
+        }
+
+        return new FieldMapping($field->getName(), $field->getType());
+    }
+}
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/MetadataTagToFieldMappingConverter.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/MetadataTagToFieldMappingConverter.php
new file mode 100644
index 0000000000..07d186b4e3
--- /dev/null
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/MetadataTagToFieldMappingConverter.php
@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of phrasea-4.0.
+ *
+ * (c) Alchemy <info@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
+
+use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
+use Alchemy\Phrasea\SearchEngine\Elastic\Structure\Tag;
+
+class MetadataTagToFieldMappingConverter
+{
+
+    public function convertTag(Tag $tag)
+    {
+        if ($tag->getType() === FieldMapping::TYPE_STRING) {
+            $fieldMapping = new StringFieldMapping($tag->getName());
+
+            $fieldMapping->disableAnalysis();
+
+            if ($tag->isAnalyzable()) {
+                $fieldMapping->addChild((new StringFieldMapping('raw'))->enableRawIndexing());
+                $fieldMapping->enableAnalysis();
+            }
+
+            return $fieldMapping;
+        }
+
+        return new FieldMapping($tag->getName(), $tag->getType());
+    }
+}
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/LocalizedFieldMapping.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/RawFieldMapping.php
similarity index 59%
rename from lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/LocalizedFieldMapping.php
rename to lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/RawFieldMapping.php
index 28615fb369..1eaf377296 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/LocalizedFieldMapping.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/RawFieldMapping.php
@@ -13,14 +13,22 @@ namespace Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
 
 use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
 
-class LocalizedFieldMapping extends FieldMapping
+class RawFieldMapping extends FieldMapping
 {
 
+    /**
+     * @param string $type
+     */
+    public function __construct($type)
+    {
+        parent::__construct('raw', $type);
+    }
+
     /**
      * @return array
      */
-    public function toArray()
+    protected function getProperties()
     {
-        return $this->buildArray([]);
+        return [ 'index' => 'not_analyzed' ];
     }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/StringFieldMapping.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/StringFieldMapping.php
index cff50020d1..b9022b2238 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/StringFieldMapping.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Mapping/StringFieldMapping.php
@@ -11,9 +11,7 @@
 
 namespace Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
 
-use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
-
-class StringFieldMapping extends FieldMapping
+class StringFieldMapping extends ComplexFieldMapping
 {
     /**
      * @var bool
@@ -30,9 +28,57 @@ class StringFieldMapping extends FieldMapping
      */
     private $searchAnalyzer = null;
 
+    /**
+     * @var string|null
+     */
+    private $termVector = null;
+
+    /**
+     * @param string $name
+     */
+    public function __construct($name)
+    {
+        parent::__construct($name, self::TYPE_STRING);
+    }
+
+    public function addAnalyzedChild($name, $analyzer)
+    {
+        $child = new self($name);
+
+        $child->setAnalyzer($analyzer);
+        $this->addChild($child);
+
+        return $this;
+    }
+
+    public function addAnalyzedChildren(array $locales)
+    {
+        $child = new StringFieldMapping('light');
+        $child->setAnalyzer('general_light');
+
+        $this->addChild($child);
+        $this->addLocalizedChildren($locales);
+
+        return $this;
+    }
+
+    public function addLocalizedChildren(array $locales)
+    {
+        foreach ($locales as $locale) {
+            /** @var StringFieldMapping $child */
+            $child = new StringFieldMapping($locale);
+
+            $child->setAnalyzer(sprintf('%s_full', $locale));
+            $this->addChild($child);
+        }
+
+        return $this;
+    }
+
     /**
      * @param string $analyzer
      * @param string|null $type
+     * @return $this
      */
     public function setAnalyzer($analyzer, $type = null)
     {
@@ -56,37 +102,63 @@ class StringFieldMapping extends FieldMapping
             default:
                 throw new \LogicException(sprintf('Invalid analyzer type "%s".', $type));
         }
+
+        return $this;
     }
 
     public function disableAnalysis()
     {
         $this->enableAnalysis = false;
+
+        return $this;
     }
 
     public function enableAnalysis()
     {
         $this->enableAnalysis = true;
+
+        return $this;
+    }
+
+    public function enableTermVectors($applyToChildren = false)
+    {
+        $this->termVector = 'with_positions_offsets';
+
+        if ($applyToChildren) {
+            /** @var self $child */
+            foreach ($this->getChildren() as $child) {
+                if ($child instanceof StringFieldMapping) {
+                    $child->enableTermVectors(false);
+                }
+            }
+        }
+
+        return $this;
     }
 
     /**
      * @return array
      */
-    public function toArray()
+    protected function getProperties()
     {
-        $configuration = [];
+        $properties = [];
 
         if ($this->analyzer) {
-            $configuration['analyzer'] = $this->analyzer;
+            $properties['analyzer'] = $this->analyzer;
         }
 
         if ($this->searchAnalyzer) {
-            $configuration['search_analyzer'] = $this->searchAnalyzer;
+            $properties['search_analyzer'] = $this->searchAnalyzer;
         }
 
         if (! $this->enableAnalysis) {
-            $configuration['index'] = 'not_analyzed';
+            $properties['index'] = 'not_analyzed';
         }
 
-        return $this->buildArray($configuration);
+        if ($this->termVector) {
+            $properties['term_vector'] = $this->termVector;
+        }
+
+        return array_replace(parent::getProperties(), $properties);
     }
 }
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/MappingBuilder.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/MappingBuilder.php
new file mode 100644
index 0000000000..9030e36e20
--- /dev/null
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/MappingBuilder.php
@@ -0,0 +1,74 @@
+<?php
+
+/*
+ * This file is part of phrasea-4.0.
+ *
+ * (c) Alchemy <info@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic;
+
+use Alchemy\Phrasea\SearchEngine\Elastic\Mapping\DateFieldMapping;
+use Alchemy\Phrasea\SearchEngine\Elastic\Mapping\StringFieldMapping;
+
+class MappingBuilder
+{
+    /**
+     * @var Mapping
+     */
+    private $mapping;
+
+    public function __construct()
+    {
+        $this->mapping = new Mapping();
+    }
+
+    /**
+     * @param string $name;
+     * @return StringFieldMapping
+     */
+    public function addStringField($name)
+    {
+        return $this->mapping->addField(new StringFieldMapping($name));
+    }
+
+    /**
+     * @param string $name
+     * @param string $format
+     * @return DateFieldMapping
+     */
+    public function addDateField($name, $format)
+    {
+        return $this->mapping->addField(new DateFieldMapping($name, $format));
+    }
+
+    /**
+     * @param string $name
+     * @param string $type
+     * @return FieldMapping
+     */
+    public function addField($name, $type)
+    {
+        return $this->mapping->addField(new FieldMapping($name, $type));
+    }
+
+    /***
+     * @param FieldMapping $fieldMapping
+     * @return FieldMapping
+     */
+    public function add(FieldMapping $fieldMapping)
+    {
+        return $this->mapping->addField($fieldMapping);
+    }
+
+    /**
+     * @return Mapping
+     */
+    public function getMapping()
+    {
+        return $this->mapping;
+    }
+}
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/Field.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/Field.php
index 5211c0318e..9c364a8843 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/Field.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/Field.php
@@ -3,6 +3,7 @@
 namespace Alchemy\Phrasea\SearchEngine\Elastic\Structure;
 
 use Alchemy\Phrasea\SearchEngine\Elastic\Exception\MergeException;
+use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
 use Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
 use Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus\Concept;
 use Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus\Helper as ThesaurusHelper;
@@ -51,7 +52,7 @@ class Field implements Typed
 
         // Thesaurus concept inference
         $xpath = $field->get_tbranch();
-        if ($type === Mapping::TYPE_STRING && !empty($xpath)) {
+        if ($type === FieldMapping::TYPE_STRING && !empty($xpath)) {
             $roots = ThesaurusHelper::findConceptsByXPath($databox, $xpath);
         } else {
             $roots = null;
@@ -77,14 +78,15 @@ class Field implements Typed
     private static function getTypeFromLegacy(databox_field $field)
     {
         $type = $field->get_type();
+
         switch ($type) {
             case databox_field::TYPE_DATE:
-                return Mapping::TYPE_DATE;
+                return FieldMapping::TYPE_DATE;
             case databox_field::TYPE_NUMBER:
-                return Mapping::TYPE_DOUBLE;
+                return FieldMapping::TYPE_DOUBLE;
             case databox_field::TYPE_STRING:
             case databox_field::TYPE_TEXT:
-                return Mapping::TYPE_STRING;
+                return FieldMapping::TYPE_STRING;
         }
 
         throw new \InvalidArgumentException(sprintf('Invalid field type "%s", expected "date", "number" or "string".', $type));
@@ -136,7 +138,7 @@ class Field implements Typed
             '%scaption.%s%s',
             $this->is_private ? 'private_' : '',
             $this->name,
-            $raw && $this->type === Mapping::TYPE_STRING ? '.raw' : ''
+            $raw && $this->type === FieldMapping::TYPE_STRING ? '.raw' : ''
         );
     }
 
@@ -203,7 +205,7 @@ class Field implements Typed
         // type so we reject only those with different types.
 
         if (($type = $other->getType()) !== $this->type) {
-            throw new MergeException(sprintf("Field %s can't be merged, incompatible types (%s vs %s)", $name, $type, $this->type));
+            //throw new MergeException(sprintf("Field %s can't be merged, incompatible types (%s vs %s)", $name, $type, $this->type));
         }
 
         if ($other->isPrivate() !== $this->is_private) {
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/GlobalStructure.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/GlobalStructure.php
index 6fcf0e2028..239072f1b5 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/GlobalStructure.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/GlobalStructure.php
@@ -2,6 +2,7 @@
 
 namespace Alchemy\Phrasea\SearchEngine\Elastic\Structure;
 
+use Alchemy\Phrasea\SearchEngine\Elastic\FieldMapping;
 use Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
 use Assert\Assertion;
 use DomainException;
@@ -76,12 +77,15 @@ final class GlobalStructure implements Structure
         Assertion::allIsInstanceOf($fields, Field::class);
         Assertion::allIsInstanceOf($flags, Flag::class);
         Assertion::allIsInstanceOf($metadata_tags, Tag::class);
+
         foreach ($fields as $field) {
             $this->add($field);
         }
+
         foreach ($flags as $flag) {
             $this->flags[$flag->getName()] = $flag;
         }
+
         foreach ($metadata_tags as $tag) {
             $this->metadata_tags[$tag->getName()] = $tag;
         }
@@ -97,7 +101,7 @@ final class GlobalStructure implements Structure
 
         $this->fields[$name] = $field;
 
-        if ($field->getType() === Mapping::TYPE_DATE) {
+        if ($field->getType() === FieldMapping::TYPE_DATE) {
             $this->date_fields[$name] = $field;
         }