data/develop/api-reference/control-flow/_index.md

---
title: Execution flow
slug: /develop/api-reference/execution-flow
---

# Execution flow

## Change execution

By default, Streamlit apps execute the script entirely, but we allow some functionality to handle control flow in your applications.

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<RefCard href="/develop/api-reference/execution-flow/st.dialog" size="full">

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<h4>Modal dialogs</h4>

Insert a modal dialog that can rerun independently from the rest of the script.

```python
@st.experimental_dialog()
def email_form():
    name = st.text_input("Name")
    email = st.text_input("Email")
```

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<RefCard href="/develop/api-reference/execution-flow/st.fragment">

<h4>Partial reruns</h4>

Define a fragment to rerun independently from the rest of the script.

```python
@st.experimental_fragment(run_every="10s")
def fragment():
    df = get_data()
    st.line_chart(df)
```

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<RefCard href="/develop/api-reference/execution-flow/st.rerun">

<h4>Rerun script</h4>

Rerun the script immediately.

```python
st.rerun()
```

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<RefCard href="/develop/api-reference/execution-flow/st.stop">

<h4>Stop execution</h4>

Stops execution immediately.

```python
st.stop()
```

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## Group multiple widgets

By default, Streamlit reruns your script everytime a user interacts with your app.
However, sometimes it's a better user experience to wait until a group of related
widgets is filled before actually rerunning the script. That's what `st.form` is for!

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<h4>Forms</h4>

Create a form that batches elements together with a “Submit" button.

```python
with st.form(key='my_form'):
    name = st.text_input("Name")
    email = st.text_input("Email")
    st.form_submit_button("Sign up")
```

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<RefCard href="/develop/api-reference/execution-flow/st.form_submit_button" size="half">

<h4>Form submit button</h4>

Display a form submit button.

```python
with st.form(key='my_form'):
    name = st.text_input("Name")
    email = st.text_input("Email")
    st.form_submit_button("Sign up")
```

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<ComponentCard href="https://github.com/kmcgrady/streamlit-autorefresh">

<Image pure alt="screenshot" src="/images/api/components/autorefresh.jpg" />

<h4>Autorefresh</h4>

Force a refresh without tying up a script. Created by [@kmcgrady](https://github.com/kmcgrady).

```python
from streamlit_autorefresh import st_autorefresh

st_autorefresh(interval=2000, limit=100,
  key="fizzbuzzcounter")
```

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<ComponentCard href="https://github.com/lukasmasuch/streamlit-pydantic">

<Image pure alt="screenshot" src="/images/api/components/pydantic.jpg" />

<h4>Pydantic</h4>

Auto-generate Streamlit UI from Pydantic Models and Dataclasses. Created by [@lukasmasuch](https://github.com/lukasmasuch).

```python
import streamlit_pydantic as sp

sp.pydantic_form(key="my_form",
  model=ExampleModel)
```

</ComponentCard>

<ComponentCard href="https://github.com/blackary/st_pages">

<Image pure alt="screenshot" src="/images/api/components/pages.jpg" />

<h4>Streamlit Pages</h4>

An experimental version of Streamlit Multi-Page Apps. Created by [@blackary](https://github.com/blackary).

```python
from st_pages import Page, show_pages, add_page_title

show_pages([ Page("streamlit_app.py", "Home", "🏠"),
  Page("other_pages/page2.py", "Page 2", ":books:"), ])
```

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