st.query_params

st.query_params provides a dictionary-like interface to access query parameters in your app's URL and is available as of Streamlit 1.30.0. It behaves similarly to st.session_state with the notable exception that keys may be repeated in an app's URL. Handling of repeated keys requires special consideration as explained below.

st.query_params can be used with both key and attribute notation. For example, st.query_params.my_key and st.query_params["my_key"]. All keys and values will be set and returned as strings. When you write to st.query_params, key-value pair prefixed with ? is added to the end of your app's URL. Each additional pair is prefixed with & instead of ?. Query parameters are cleared when navigating between pages in a multipage app.

For example, consider the following URL:

https://your_app.streamlit.app/?first_key=1&second_key=two&third_key=true

The parameters in the URL above will be accessible in st.query_params as:

{
    "first_key" : "1",
    "second_key" : "two",
    "third_key" : "true"
}

This means you can use those parameters in your app like this:

# You can read query params using key notation
if st.query_params["first_key"] == "1":
    do_something()

# ...or using attribute notation
if st.query_params.second_key == "two":
    do_something_else()

# And you can change a param by just writing to it
st.query_params.first_key = 2  # This gets converted to str automatically

Repeated keys

When a key is repeated in your app's URL (?a=1&a=2&a=3), dict-like methods will return only the last value. In this example, st.query_params["a"] returns "3". To get all keys as a list, use the .get_all() method shown below. To set the value of a repeated key, assign the values as a list. For example, st.query_params.a = ["1", "2", "3"] produces the repeated key given at the beginning of this paragraph.

Limitation

st.query_params can't get or set embedding settings as described in Embed your app. st.query_params.embed and st.query_params.embed_options will raise an AttributeError or StreamlitAPIException when trying to get or set their values, respectively.