Streamlit

A Python framework for building data and ML apps as a script — widgets, charts, and layout from normal Python code.

Category
Visualization
Difficulty
Beginner
When to use
You want a quick internal tool or demo around a model and don't want to touch frontend code.
When not to use
You're building a customer-facing product or anything with custom interactions — a real frontend framework will serve you better.
Alternatives
Gradio Dash Panel Next.js

At a glance

FieldValue
CategoryData / ML app framework
DifficultyBeginner
When to useInternal tools, demos, data exploration UIs
When not to useCustomer-facing products, complex interactions
AlternativesGradio, Dash, Panel

What it is

A Streamlit app is a Python script that runs top-to-bottom every time a widget changes. Calls like st.button, st.slider, st.dataframe, and st.plotly_chart render widgets and output. Caching decorators (@st.cache_data, @st.cache_resource) avoid recomputing on every rerun.

When we reach for it at Ephizen

  • Internal dashboards for a model’s predictions on incoming data.
  • Demos to stakeholders of a new classifier or RAG prototype.
  • Quick “let me click around my data” UIs that would otherwise be a one-off notebook.
  • Sharing a model with non-technical teammates who don’t want to run code.

Getting started

import streamlit as st
from my_model import predict

st.title("Sentiment Demo")
text = st.text_area("Text", "I love this product")
if st.button("Classify"):
    label, score = predict(text)
    st.metric(label, f"{score:.2f}")
streamlit run app.py

Gotchas

  • The rerun-the-script model is simple but awkward for stateful flows — use st.session_state explicitly.
  • Not designed for heavy concurrent traffic. If you hit scaling problems, you’re probably past the point where Streamlit is the right tool.
  • Theming and layout are limited. For pixel-perfect UIs, use a real frontend.

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