diff --git a/src/Protocol/CompletionItem.php b/src/Protocol/CompletionItem.php
index e883582..09cef19 100644
--- a/src/Protocol/CompletionItem.php
+++ b/src/Protocol/CompletionItem.php
@@ -63,6 +63,14 @@ class CompletionItem
      */
     public $insertText;
 
+    /**
+     * The format of the insert text. The format applies to both the `insertText` property
+     * and the `newText` property of a provided `textEdit`.
+     *
+     * @var InsertTextFormat|null
+     */
+    public $insertTextFormat;
+
     /**
      * A range of text that should be replaced by this completion item.
      *
diff --git a/src/Protocol/InsertTextFormat.php b/src/Protocol/InsertTextFormat.php
new file mode 100644
index 0000000..3a05155
--- /dev/null
+++ b/src/Protocol/InsertTextFormat.php
@@ -0,0 +1,28 @@
+<?php
+declare(strict_types = 1);
+
+namespace LanguageServer\Protocol;
+
+/**
+ * Defines whether the insert text in a completion item should be interpreted as
+ * plain text or a snippet.
+ */
+abstract class InsertTextFormat
+{
+    /**
+     * The primary text to be inserted is treated as a plain string.
+     */
+    const PLAIN_TEXT = 1;
+
+    /**
+     * The primary text to be inserted is treated as a snippet.
+     *
+     * A snippet can define tab stops and placeholders with `$1`, `$2`
+     * and `${3:foo}`. `$0` defines the final tab stop, it defaults to
+     * the end of the snippet. Placeholders with equal identifiers are linked,
+     * that is typing in one will update others too.
+     *
+     * See also: https://github.com/Microsoft/vscode/blob/master/src/vs/editor/contrib/snippet/common/snippet.md
+     */
+    const SNIPPET = 2;
+}