diff --git a/lib/config.js b/lib/config.js
index 6e24a72..3ac33bc 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -37,6 +37,11 @@ var envFromShell = process.env.NODE_ENV;
 
 var env = envFromBrowser || envFromShell || DEFAULT_ENV;
 
+if (!env.match(/^(production|staging|cam)$/)) { 
+  throw new Error('Panoptes Javascript Client Error: Invalid Environment; ' +
+    'try setting NODE_ENV to "staging" instead of "'+envFromShell+'".');
+}
+
 module.exports = {
   host: hostFromBrowser || hostFromShell || API_HOSTS[env],
   clientAppID: appFromBrowser || appFromShell || API_APPLICATION_IDS[env],