diff --git a/auth/integration_test/src/integration_test.cc b/auth/integration_test/src/integration_test.cc
index 83ddf1fcda..37ceb8b495 100644
--- a/auth/integration_test/src/integration_test.cc
+++ b/auth/integration_test/src/integration_test.cc
@@ -389,10 +389,11 @@ TEST_F(FirebaseAuthTest, TestTokensAndAuthStateListeners) {
 }
 
 static std::string GenerateEmailAddress() {
-  std::string email =
-      "random_user_" +
-      std::to_string(app_framework::GetCurrentTimeInMicroseconds()) +
-      "@gmail.com";
+  char time_string[22];
+  snprintf(time_string, 22, "%d", app_framework::GetCurrentTimeInMicroseconds());
+  std::string email = "random_user_";
+  email.append(time_string);
+  email.append("@gmail.com");
   LogDebug("Generated email address: %s", email.c_str());
   return email;
 }
diff --git a/messaging/integration_test/src/integration_test.cc b/messaging/integration_test/src/integration_test.cc
index 34845e477b..1eca7a34c8 100644
--- a/messaging/integration_test/src/integration_test.cc
+++ b/messaging/integration_test/src/integration_test.cc
@@ -386,7 +386,10 @@ static std::string ConstructHtmlToSendMessage(
        "document.write('<h1>Failed to send notification.</h1>');"
        "document.write('Status '+xhttp.status+': '+xhttp.response);"
        "}},";
-  h += std::to_string(delay_seconds * 1000) + ");}</script>";
+  char delay_seconds_string[22];
+  snprintf(delay_seconds_string, 22, "%d", delay_seconds);
+  h += delay_seconds_string;
+  h += ");}</script>";
   return h;
 }