diff --git a/api/serve.mjs b/api/serve.mjs
index 1b6f493..5f5ac3e 100644
--- a/api/serve.mjs
+++ b/api/serve.mjs
@@ -1,5 +1,5 @@
 import send from 'koa-send'
-import defaults from './defaults'
+import defaults from './defaults.mjs'
 
 export function serve(docRoot, pathname, options = {}) {
   options.root = docRoot