streamlit-js-eval
A custom Streamlit component to evaluate arbitrary Javascript expressions.
Decision gist · record as of 2026-08-14
Yes, if you need browser API access in Streamlit and accept the maintenance risk. Install friction is low and the package has no known vulnerabilities. However, verify the license terms first (currently unclear), and be aware that maintenance is aging—last release was 217 days ago. The known limitation with st.button in branching contexts may affect some use cases; check whether the bootstrapButton workaround suits your needs.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python >=3.8 and a running Streamlit app; JavaScript execution depends on browser environment, so it only works in deployed or local Streamlit apps, not in headless contexts.
- Low friction: pure Python wheel with only streamlit as a runtime dependency.
- Maintenance status is aging—last commit was 217 days ago, though the repository is still active and not archived.
License · maintenance · safety
(unclear) — License status is unclear; the package declares no SPDX identifier or raw license text. Verify the actual license terms before use in proprietary or restricted contexts.
last release 2026-01-09 (217 days) · last repo commit 2026-01-13 · 93 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 120,848 downloads/mo, #12,008 on PyPI
Alternatives
Verify before relying
pip install streamlit-js-eval
import streamlit as st
from streamlit_js_eval import streamlit_js_eval
width = streamlit_js_eval(js_expressions='screen.width', key='SCR')
st.write(f"Screen width is {width}")- Whether the 'aging' maintenance status (217 days since last release) signals active development or dormancy; repo is not archived but commit frequency is unclear.
- Actual license terms and any compatibility restrictions, given the unclear license_treatment.
- Current state of the known limitation with st.button in branching contexts and whether bootstrapButton workaround is stable.
What it is and what it does
Streamlit-js-eval is a custom Streamlit component that bridges Python and the browser by executing arbitrary JavaScript expressions and returning their results. It exposes browser APIs—geolocation, clipboard, device dimensions, user agent, language preferences, and Android sharing—that are either unavailable or cumbersome to access from pure Python Streamlit code. The package includes convenience wrappers for common tasks like `get_geolocation()` and `get_page_location()`, with error handling for permission denials and failures.
You use it by calling `streamlit_js_eval()` with a JavaScript expression string and a unique key, or by invoking pre-built functions for specific browser capabilities. It's useful when your Streamlit app needs to adapt to the user's device or environment—detecting mobile screens, reading cookies, writing to clipboard, or requesting location permission—without leaving the Streamlit framework.
Use it for
- Detect whether a user is on a mobile device by checking screen width and adapting the UI layout accordingly.
- Request and retrieve user geolocation with error handling for permission denial or unavailable position.
- Copy data to the user's clipboard or read clipboard contents programmatically from a Streamlit app.
- Access browser metadata like user agent, language preference, or page URL components for analytics or personalization.
- Implement Android-specific features like the native share sheet in a Streamlit web app.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need browser API access in Streamlit and accept the maintenance risk.
Install friction is low and the package has no known vulnerabilities. However, verify the license terms first (currently unclear), and be aware that maintenance is aging—last release was 217 days ago. The known limitation with st.button in branching contexts may affect some use cases; check whether the bootstrapButton workaround suits your needs.
Install
streamlit-js-eval on PyPI
Before you install
Low friction: pure Python wheel with only streamlit as a runtime dependency. Maintenance status is aging—last commit was 217 days ago, though the repository is still active and not archived.
Requires Python >=3.8 and a running Streamlit app; JavaScript execution depends on browser environment, so it only works in deployed or local Streamlit apps, not in headless contexts.
License in practice
License status is unclear; the package declares no SPDX identifier or raw license text. Verify the actual license terms before use in proprietary or restricted contexts.
Quickstart
pip install streamlit-js-eval
import streamlit as st
from streamlit_js_eval import streamlit_js_eval
width = streamlit_js_eval(js_expressions='screen.width', key='SCR')
st.write(f"Screen width is {width}")Verify before relying
- Whether the 'aging' maintenance status (217 days since last release) signals active development or dormancy; repo is not archived but commit frequency is unclear.
- Actual license terms and any compatibility restrictions, given the unclear license_treatment.
- Current state of the known limitation with st.button in branching contexts and whether bootstrapButton workaround is stable.
Package facts
| License | Not declared unclear |
| Python support | Supports the current Python release >=3.8 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagestreamlit |
| Maintenance | Aging 217 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 120,848 / month, #12,008 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
Evidence: streamlit_js_eval-1.0.0-py3-none-any.whl
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See also streamlit-autorefresh · streamlit-javascript · streamlit-cookies-controller · extra-streamlit-components · streamlit-plotly-events · streamlit-pdf-viewer · streamlit-avatar · streamlit-ace · st-theme · streamlit-msal