diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -3187,6 +3187,7 @@
     'PhabricatorIteratorFileUploadSource' => 'applications/files/uploadsource/PhabricatorIteratorFileUploadSource.php',
     'PhabricatorJIRAAuthProvider' => 'applications/auth/provider/PhabricatorJIRAAuthProvider.php',
     'PhabricatorJSONConfigType' => 'applications/config/type/PhabricatorJSONConfigType.php',
+    'PhabricatorJSONDocumentEngine' => 'applications/files/document/PhabricatorJSONDocumentEngine.php',
     'PhabricatorJSONExportFormat' => 'infrastructure/export/format/PhabricatorJSONExportFormat.php',
     'PhabricatorJavelinLinter' => 'infrastructure/lint/linter/PhabricatorJavelinLinter.php',
     'PhabricatorJiraIssueHasObjectEdgeType' => 'applications/doorkeeper/edge/PhabricatorJiraIssueHasObjectEdgeType.php',
@@ -8800,6 +8801,7 @@
     'PhabricatorIteratorFileUploadSource' => 'PhabricatorFileUploadSource',
     'PhabricatorJIRAAuthProvider' => 'PhabricatorOAuth1AuthProvider',
     'PhabricatorJSONConfigType' => 'PhabricatorTextConfigType',
+    'PhabricatorJSONDocumentEngine' => 'PhabricatorTextDocumentEngine',
     'PhabricatorJSONExportFormat' => 'PhabricatorExportFormat',
     'PhabricatorJavelinLinter' => 'ArcanistLinter',
     'PhabricatorJiraIssueHasObjectEdgeType' => 'PhabricatorEdgeType',
diff --git a/src/applications/files/document/PhabricatorDocumentRef.php b/src/applications/files/document/PhabricatorDocumentRef.php
--- a/src/applications/files/document/PhabricatorDocumentRef.php
+++ b/src/applications/files/document/PhabricatorDocumentRef.php
@@ -116,6 +116,10 @@
     }
 
     $snippet = $this->getSnippet();
+    if (!preg_match('/^\s*[{[]/', $snippet)) {
+      return false;
+    }
+
     return phutil_is_utf8($snippet);
   }
 
diff --git a/src/applications/files/document/PhabricatorJSONDocumentEngine.php b/src/applications/files/document/PhabricatorJSONDocumentEngine.php
new file mode 100644
--- /dev/null
+++ b/src/applications/files/document/PhabricatorJSONDocumentEngine.php
@@ -0,0 +1,59 @@
+<?php
+
+final class PhabricatorJSONDocumentEngine
+  extends PhabricatorTextDocumentEngine {
+
+  const ENGINEKEY = 'json';
+
+  public function getViewAsLabel(PhabricatorDocumentRef $ref) {
+    return pht('View as JSON');
+  }
+
+  protected function getDocumentIconIcon(PhabricatorDocumentRef $ref) {
+    return 'fa-database';
+  }
+
+  protected function getContentScore(PhabricatorDocumentRef $ref) {
+    if (preg_match('/\.json\z/', $ref->getName())) {
+      return 2000;
+    }
+
+    if ($ref->isProbablyJSON()) {
+      return 1750;
+    }
+
+    return 500;
+  }
+
+  protected function newDocumentContent(PhabricatorDocumentRef $ref) {
+    $raw_data = $this->loadTextData($ref);
+
+    try {
+      $data = phutil_json_decode($raw_data);
+
+      if (preg_match('/^\s*\[/', $raw_data)) {
+        $content = id(new PhutilJSON())->encodeAsList($data);
+      } else {
+        $content = id(new PhutilJSON())->encodeFormatted($data);
+      }
+
+      $message = null;
+      $content = PhabricatorSyntaxHighlighter::highlightWithLanguage(
+        'json',
+        $content);
+    } catch (PhutilJSONParserException $ex) {
+      $message = $this->newMessage(
+        pht(
+          'This document is not valid JSON: %s',
+          $ex->getMessage()));
+
+      $content = $raw_data;
+    }
+
+    return array(
+      $message,
+      $this->newTextDocumentContent($content),
+    );
+  }
+
+}