diff --git a/packages/selenium-ide/src/api/index.js b/packages/selenium-ide/src/api/index.js
index 10b68f0ab..7c22fa52c 100644
--- a/packages/selenium-ide/src/api/index.js
+++ b/packages/selenium-ide/src/api/index.js
@@ -17,6 +17,7 @@
 
 import Router from '../router'
 import apiv1 from './v1'
+import Manager from '../plugin/manager'
 
 const router = new Router()
 router.use('/v1', apiv1)
@@ -26,6 +27,16 @@ export default function(message, _backgroundPage, sendResponse) {
   // The sender is always the background page since he is the one listening to the event
   // message.sender is the external extension id
   if (message.uri) {
+    if (
+      message.uri !== '/health' &&
+      message.uri !== '/register' &&
+      !Manager.hasPlugin(message.payload.sender)
+    ) {
+      return sendResponse({
+        error:
+          'Plugin is not registered with Selenium IDE, send a request to /register first',
+      })
+    }
     router
       .run(message)
       .then(sendResponse)
diff --git a/packages/selenium-ide/src/api/v1/index.js b/packages/selenium-ide/src/api/v1/index.js
index 61083d912..cb97682cc 100644
--- a/packages/selenium-ide/src/api/v1/index.js
+++ b/packages/selenium-ide/src/api/v1/index.js
@@ -63,8 +63,8 @@ router.get('/project', (_req, res) => {
 })
 
 router.post('/project', (req, res) => {
+  const plugin = Manager.getPlugin(req.sender)
   if (req.project) {
-    const plugin = Manager.getPlugin(req.sender)
     if (!UiState.isSaved()) {
       ModalState.showAlert({
         title: 'Open project without saving',