diff --git a/lib/carto/external.js b/lib/carto/external.js
index <HASH>..<HASH> 100644
--- a/lib/carto/external.js
+++ b/lib/carto/external.js
@@ -228,7 +228,7 @@ External.types = [
         }
     },
     {
-        extension: /\.geojson/,
+        extension: /\.geojson|\.json/,
         datafile: function(d, c) { c(null, d.path()) },
         ds_options: {
             type: 'ogr',
Accept .json extension as geojson.