diff --git a/package.json b/package.json
index 5aeca26..6d26b73 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "cep-promise",
-  "version": "4.0.2",
+  "version": "4.0.3",
   "description": "Busca por CEP integrado diretamente aos serviços dos Correios e ViaCEP",
   "main": "dist/cep-promise.min.js",
   "module": "dist/cep-promise.min.js",
diff --git a/src/services/viacep.js b/src/services/viacep.js
index 2545887..d568b3e 100644
--- a/src/services/viacep.js
+++ b/src/services/viacep.js
@@ -9,11 +9,14 @@ export default function fetchViaCepService (cepWithLeftPad, proxyURL = '') {
     method: 'GET',
     mode: 'cors',
     headers: {
-      'content-type': 'application/json;charset=utf-8',
-      'user-agent': ''
+      'content-type': 'application/json;charset=utf-8'
     }
   }
 
+  if (typeof window == 'undefined') {
+    options.headers['user-agent'] = 'cep-promise'
+  }
+
   return fetch(url, options)
     .then(analyzeAndParseResponse)
     .then(checkForViaCepError)