st.stop() in Streamlit

The st.stop() method is a Streamlit control flow command that immediately stops the execution of your Streamlit script at that line.

👉 Any code written after st.stop() will not run.

Syntax

st.stop()

No arguments are required.

When to Use st.stop()

You typically use st.stop() in situations like:

Input validation: Stop execution when user input is missing or invalid.
Early exit: Show only part of the page under certain conditions.
Authentication / Access control: Stop the app before showing private content.

Example: Stop when required input is missing.

Python

# Importing the Streamlit library
import streamlit as st

st.title("Example: Using st.stop()")

# Ask for user input
name = st.text_input("Enter your name:")

# If no input, show a message and stop further execution
if not name:
    st.warning("Please enter your name to continue!")
    st.stop()

# This part runs only if the user entered a name
st.success(f"Welcome, {name}! 🎉")

Explanation

When the user hasn’t entered a name:
Streamlit shows the warning.
st.stop() halts execution — so the success message doesn’t appear.
Once the user types their name:
The condition becomes false, and the script continues.

Example: Use in multi-step workflows.

Python

import streamlit as st
import pandas as pd

st.header("Step 1: Upload a file")

uploaded_file = st.file_uploader("Upload your CSV file")

if uploaded_file is None:
    st.info("Please upload a file to continue.")
    st.stop()

st.header("Step 2: Display Data")

df = pd.read_csv(uploaded_file)
st.dataframe(df)

✔ The file upload must happen first.
🚫 Without a file, no error occurs — st.stop() cleanly ends execution.

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