As described in this Github issue 84, it is very easy to write unsafe apps when developers have the ability to code in HTML. The idea is that users should always be able to trust Streamlit apps. So we have turned HTML off by default in Streamlit and will be removing the option to turn it on at some point in the future. (Update: We heard you, and have no plans to deprecate allow_unsafe_html! )
However, there are some legitimate use cases for writing HTML today to get around limitations in Streamlit’s current feature set. Some examples are:


Layout: laying items side by side, changing margin/padding/alignment properties, at.

Text-based diagrams: see this example 558 from a user working on NLP.

(Rest assured, we are currently working on solutions to the use-cases above. You will hear about them very soon!)
If you’re using HTML in Streamlit, we would like to hear from you! Let us know:

Why are you using it?
Any thoughts on what you’d like to see in Streamlit if you did not have the ability to use HTML?

Thanks!