app.py

import gradio as gr

def flip_text(x):
    return x[::-1]

demo = gr.Blocks()

with demo:
    gr.Markdown(
    """# Flip Text!
    Start typing below to see the output."""
    )
    input = gr.Textbox(placeholder="Flip this text")
    output = gr.Textbox()
    input.change(fn=flip_text, inputs=input, outputs=output)
demo.launch()