diff --git a/engine/app.cpp b/engine/app.cpp
index 924acd7..122ed01 100644
--- a/engine/app.cpp
+++ b/engine/app.cpp
@@ -127,6 +127,22 @@ void App::download(std::string filename, std::function<void(float)> progress)
     }
 }
 
+bool App::check_license()
+{
+    CURL *curl = curl_easy_init();
+    if (curl)
+    {
+        std::string url = "http://omigamedev.com/panopainter/79516B99-8E67-40AD-B12F-149A5A9C2E15";
+        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
+        curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L);
+        auto err = curl_easy_perform(curl);
+        curl_easy_cleanup(curl);
+        if (err == CURLcode::CURLE_OK)
+            return true;
+    }
+    return false;
+}
+
 void App::upload(std::string filename, std::string name, std::function<void(float)> progress)
 {
     CURL *curl;
diff --git a/engine/app.h b/engine/app.h
index b857c2a..efb53df 100644
--- a/engine/app.h
+++ b/engine/app.h
@@ -148,6 +148,7 @@ public:
     void cloud_browse();
     void upload(std::string filename, std::string name = "", std::function<void(float)> progress = nullptr);
     void download(std::string filename, std::function<void(float)> progress = nullptr);
+    bool check_license();
     
     std::shared_ptr<NodeProgressBar> show_progress(const std::string& title);
 
diff --git a/engine/canvas.cpp b/engine/canvas.cpp
index 4f17e9c..b7b4492 100644
--- a/engine/canvas.cpp
+++ b/engine/canvas.cpp
@@ -911,6 +911,8 @@ void ui::Canvas::import_equirectangular_thread(std::string file_path)
 
 void ui::Canvas::export_equirectangular(std::string file_path)
 {
+    if (!App::I.check_license())
+        return;
     std::thread t(&ui::Canvas::export_equirectangular_thread, this, file_path);
     t.detach();
 }
@@ -1152,6 +1154,8 @@ void ui::Canvas::inject_xmp(std::string jpg_path)
 
 void ui::Canvas::export_anim(std::string data_path)
 {
+    if (!App::I.check_license())
+        return;
     // save viewport and clear color states
     GLint vp[4];
     GLfloat cc[4];
@@ -1263,6 +1267,8 @@ void ui::Canvas::export_anim(std::string data_path)
 
 void ui::Canvas::export_cubes(std::string data_path)
 {
+    if (!App::I.check_license())
+        return;
 #ifdef __OBJC__
     NSMutableArray* files = [NSMutableArray array];
 #endif
@@ -1343,6 +1349,8 @@ void ui::Canvas::export_cubes(std::string data_path)
 
 void ui::Canvas::project_save(std::string file_path)
 {
+    if (!App::I.check_license())
+        return;
     std::thread t(&ui::Canvas::project_save_thread, this, file_path);
     t.detach();
 }
diff --git a/engine/main.cpp b/engine/main.cpp
index 9b205a1..b608b07 100644
--- a/engine/main.cpp
+++ b/engine/main.cpp
@@ -264,6 +264,9 @@ int main(int argc, char** argv)
     WNDCLASS wc;
     PIXELFORMATDESCRIPTOR pfd;
 
+    if (!App::I.check_license())
+        return -1;
+
     if (argc == 1)
         App::I.initLog();