Fixing Streamlit's Plotly Chart Deprecation Warning

Jan 17, 2026 by Editorial Team 52 views

Hey there, data enthusiasts! Ever run into a pesky deprecation warning while using st.plotly_chart in Streamlit? Specifically, the one about **kwargs? Well, you're not alone! Let's dive into this issue and get your charts looking sharp without the annoying warnings. We'll break down the problem, provide a simple code example, and walk through the fix. This guide is tailored for both beginners and seasoned developers, so let's get started!

The Problem: `st.plotly_chart` and the `width` Parameter

So, the main issue revolves around the st.plotly_chart function and how it handles keyword arguments (kwargs). In the latest versions of Streamlit, there's a deprecation warning related to passing **kwargs, even when you're not explicitly using them. This warning pops up when you use documented parameters like width="content" or height. It's a bit of a head-scratcher, right? You're using the function as intended, and yet, there's a warning. The core of the problem lies in the way Streamlit processes these parameters behind the scenes. It seems like the width and height parameters, which are perfectly valid, trigger the **kwargs warning, even though they're not technically part of the deprecated arguments.

Detailed Explanation of the Deprecation Warning

The deprecation warning is a signal from Streamlit developers that certain features are on their way out. In this case, it's about how st.plotly_chart accepts and processes extra keyword arguments. The warning message usually advises you to use the config argument instead to specify Plotly configuration options. However, when you're simply trying to control the size of your chart using width or height, this advice doesn't directly apply, which adds to the confusion. This issue specifically affects users who are trying to control the size and layout of their plots using the documented width and height parameters, leading to unnecessary warnings and potentially causing confusion about how to properly use the function.

Reproducible Code Example: Seeing the Warning in Action

Let's get our hands dirty with a simple example that triggers the warning. This will help you see the problem first-hand and understand how to reproduce it. This is a common situation for many Streamlit users, especially those new to the platform.

import plotly.graph_objects as go
import streamlit as st

# Create a sample Plotly figure
fig = go.Figure()
fig.add_trace(go.Barpolar(r=[1], theta=[0], width=[120]))
fig.update_layout(width=500, height=360)

# Display the chart with width="content"
st.plotly_chart(fig, width="content")

Explanation of the Code

In this code, we create a basic polar bar chart using Plotly. We then use st.plotly_chart to display it within our Streamlit app. The key part is width="content". This tells Streamlit to adjust the chart's width to fit its content. Despite using a perfectly valid parameter, this line will likely trigger the deprecation warning. This happens because the st.plotly_chart function, in its current implementation, seems to flag the use of width or height as an indirect use of the now-deprecated **kwargs.

Steps to Reproduce the Warning

Reproducing the warning is straightforward. Here's a step-by-step guide:

Set up your Streamlit environment: Make sure you have Streamlit and Plotly installed. If not, install them using pip install streamlit plotly.
Create a Python file: Save the code example above in a Python file (e.g., plotly_example.py).
Run the Streamlit app: Open your terminal, navigate to the directory where you saved the file, and run streamlit run plotly_example.py.
Observe the output: You should see your chart displayed in the Streamlit app, along with the deprecation warning in your terminal. This confirms that the issue is present and that you've successfully reproduced it. This setup is a common starting point for many Streamlit projects that use interactive charts.

Understanding the Root Cause

The deprecation warning is triggered because the st.plotly_chart function is designed to handle a wide range of parameters. It appears that the function's internal logic flags the use of width or height as a potential use of the deprecated **kwargs. This is likely due to how the function processes and passes arguments to the underlying Plotly library. While width and height are explicitly supported parameters, the function's architecture might not fully distinguish them from other, less-defined keyword arguments. This results in the warning, even though you are correctly using the intended parameters.

The Fix: Staying Updated and Following Best Practices

Unfortunately, there isn't a direct fix you can implement in your code to eliminate this warning. The warning is within the Streamlit library itself, so the solution requires an update from the Streamlit developers. The best course of action is to:

Keep Streamlit Updated: Ensure you're using the latest version of Streamlit. Developers are constantly working on fixes and improvements, and a newer version might address this issue.
Monitor Streamlit's Updates: Keep an eye on Streamlit's release notes and GitHub repository for updates related to st.plotly_chart and **kwargs. The developers might release a patch that specifically addresses this warning.
Use the config Argument (When Applicable): If you need to configure Plotly options, use the config argument as suggested in the warning. This is the recommended way to pass configuration settings to your charts. This approach aligns with the future direction of the library and helps to avoid potential compatibility issues.

The Importance of Staying Updated

Keeping your Streamlit installation up-to-date is crucial for several reasons. First, it ensures you have access to the latest features and improvements. Second, it helps you avoid known bugs and compatibility issues. Third, it ensures your code aligns with the evolving best practices of the library. Staying updated is a proactive approach to maintaining a smooth development workflow and ensuring your Streamlit applications remain functional and efficient.

Conclusion: Navigating the Deprecation Warning

While the st.plotly_chart **kwargs deprecation warning can be a bit confusing, it's essential to understand its cause and how to address it. By staying updated with Streamlit, following best practices, and monitoring for library updates, you can minimize the impact of this warning and ensure your data visualizations remain clean and effective. Don't let a warning message deter you; with a bit of knowledge and the right approach, you can create stunning interactive charts with Streamlit!

Summary of Key Takeaways

The deprecation warning for st.plotly_chart **kwargs can appear when using width or height.
The issue is likely due to the function's internal handling of parameters.
The best solution is to keep Streamlit updated and follow the library's recommended practices.
Use the config argument for Plotly configuration options if needed.

Additional Resources

Streamlit Documentation: The official Streamlit documentation is your go-to resource for everything Streamlit.
Plotly Documentation: Learn more about creating interactive charts with Plotly.
Streamlit GitHub Repository: Stay informed about the latest updates and contribute to the Streamlit community.

That's all for now, folks! Happy charting!