Streamlit Apps in Wizard Apps live in apps/wizard/app_pages/ . Run with make wizard or .venv/bin/etlwiz . Creating a New App Create apps/wizard/app_pages/your_app/app.py : import streamlit as st st . set_page_config ( page_title = "Wizard: Your App" , page_icon = "🪄" , layout = "wide" ) def main ( ) : st . title ( "Your App" ) main ( ) Register in apps/wizard/config/config.yml under a section's apps list: - title : "Your App" alias : your - app entrypoint : app_pages/your_app/app.py description : "What it does" maintainer : "@slack-handle" icon : ":material/icon:" Key Utilities

Caching (supports ttl, show_time, works outside Streamlit too)

from apps . wizard . utils . components import st_cache_data @st_cache_data ( custom_text = "Loading..." , ttl = "1h" )

URL-synced widgets (shareable state)

from apps . wizard . utils . components import url_persist url_persist ( st . selectbox ) ( label = "Option" , options = [ "a" , "b" ] , key = "my_key" )

⚠️ Booleans stored as "True"/"False" strings in URL

Charts

from apps . wizard . utils . components import grapher_chart , grapher_chart_from_url grapher_chart ( catalog_path = "grapher/ns/ver/ds#var" ) grapher_chart ( variable_id = 123 , selected_entities = [ "France" ] , tab = "map" )

Data loading

from apps . wizard . utils . cached import load_variables_in_dataset , load_variable_data

Environment & DB

from etl . config import OWID_ENV

.base_site, .indicators_url, .data_api_url

from etl . db import get_engine from sqlalchemy . orm import Session Components ( apps.wizard.utils.components ) st_horizontal() — flexbox row context manager Pagination(items, items_per_page, pagination_key) — paginated lists grapher_chart() / grapher_chart_from_url() — OWID charts st_wizard_page_link(alias) — link to another Wizard page st_tag(name, color, icon) / tag_in_md() — colored badges st_toast_success() / st_toast_error() — toast notifications preview_file(path) — code preview in expander Rules st.set_page_config() must be the first Streamlit command Use @st_cache_data for expensive operations Use url_persist() for shareable widget state Material icons: :material/icon_name: (Google Material Symbols) HTTP requests: always timeout=30 and .raise_for_status()