diff --git a/flux-pywebio.py b/flux-pywebio.py
index 4743cd6..6a6813a 100644
--- a/flux-pywebio.py
+++ b/flux-pywebio.py
@@ -44,6 +44,9 @@ def set_dir():
         dirpath = False
     return dirpath
 
+def chk_prompt_len(prompt):
+    if len(prompt) > 370:
+        return "Prompt too long"
 
 def flux_run(prompt, height, width, num_images_per_prompt, num_inference_steps, max_sequence_length, dirpath):
     # FIX: add check to make sure there isn't already one running from another source (e.g. from phone when on computer)
@@ -92,7 +95,7 @@ def btn_click(btn_val):
 def main():  # PyWebIO application function
     # TODO: figure out how to put the labels in line with the inputs and make the number ones smaller
     put_text("Prompt:", inline=True)
-    pin.put_input("prompt", type="text", value=default_prompt)
+    pin.put_input("prompt", type="text", value=default_prompt, validate=chk_prompt_len)
     put_text("width:", inline=True)
     pin.put_input("width", type="number", value=default_width)
     put_text("height:", inline=True)