# Reactive Interfaces

Finally, we cover how to get Gradio demos to refresh automatically or continuously stream data.

## Live Interfaces

You can make interfaces automatically refresh by setting `live=True` in the interface. Now the interface will recalculate as soon as the user input changes.

```python
import gradio as gr

def calculator(num1, operation, num2):
    if operation == "add":
        return num1 + num2
    elif operation == "subtract":
        return num1 - num2
    elif operation == "multiply":
        return num1 * num2
    elif operation == "divide":
        return num1 / num2

demo = gr.Interface(
    calculator,
    [
        "number",
        gr.Radio(["add", "subtract", "multiply", "divide"]),
        "number"
    ],
    "number",
    live=True,
)
demo.launch()

```


Note there is no submit button, because the interface resubmits automatically on change.

## Streaming Components

Some components have a "streaming" mode, such as `Audio` component in microphone mode, or the `Image` component in webcam mode. Streaming means data is sent continuously to the backend and the `Interface` function is continuously being rerun.

The difference between `gr.Audio(source='microphone')` and `gr.Audio(source='microphone', streaming=True)`, when both are used in `gr.Interface(live=True)`, is that the first `Component` will automatically submit data and run the `Interface` function when the user stops recording, whereas the second `Component` will continuously send data and run the `Interface` function _during_ recording.

Here is example code of streaming images from the webcam.

```python
import gradio as gr
import numpy as np

def flip(im):
    return np.flipud(im)

demo = gr.Interface(
    flip,
    gr.Image(sources=["webcam"], streaming=True),
    "image",
    live=True,
    api_name="predict",
)
demo.launch()

```

Streaming can also be done in an output component. A `gr.Audio(streaming=True)` output component can take a stream of audio data yielded piece-wise by a generator function and combines them into a single audio file. For a detailed example, see our guide on performing [automatic speech recognition](/guides/real-time-speech-recognition) with Gradio.