shiny

library1.6.3pypypi✓ verified 85d ago

Shiny is an open-source web development framework for Python, enabling data scientists and developers to build interactive web applications and dashboards with purely Python code. Maintained by Posit, it is under active development with frequent releases that introduce features like OpenTelemetry integration, toast notifications, AI-powered test generation, and application bookmarking. It allows for the creation of rich user interfaces that react dynamically to user input.

web-framework data observability

pip install shiny

github ↗package ↗homepage ↗docs ↗

INSTALL

IMPORT

SIG · SHINY

shiny

web-frameworkpythonv1.6.3

Install

5.7s avg

Import

942ms

Disk

68MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.6.3 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.920 runs

installs and imports cleanly · install 0.0s · import 0.972s · 67.2MB

glibc

py 3.10–3.920 runs

installs and imports cleanly · install 5.7s · import 0.911s · 67MB

68MB installed

● package 68MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

App

✓ from shiny import App

✓ from shiny import ui

render

✓ from shiny import render

reactive

✓ from shiny import reactive

input

✓ from shiny.express import input

✗ from shiny import input

`input` is typically used implicitly within `@reactive` or `@render` functions, or directly imported from `shiny.express` for Express mode applications. In Core mode, it's passed as an argument to the `server` function.

output

✓ from shiny.express import output

✗ from shiny import output

Similar to `input`, `output` is implicitly available in Express mode or passed to the `server` function in Core mode.

session

✓ from shiny.express import session

✗ from shiny import session

Similar to `input` and `output`, `session` is implicitly available in Express mode or passed to the `server` function in Core mode.

This minimal Shiny application demonstrates a basic slider input (`ui.input_slider`) and a reactive text output (`ui.output_text_verbatim`). The `server` function uses the `@render.text` decorator to reactively display the current value of the slider.

from shiny import App, ui, render app_ui = ui.page_fluid( ui.input_slider("n", "N", 0, 100, 20), ui.output_text_verbatim("txt"), ) def server(input, output, session): @render.text def txt(): return f"The value of N is {input.n()}" app = App(app_ui, server)

shiny --version

Debug

Known issues

breakingBreaking changes in `shiny.playwright.controllers` for testing. `.expect_inverse()` now requires a `bool` (use `False` for previous behavior). `.expect_layout()` was renamed to `.expect_fluid()` and also requires a `bool` (use `True` for previous behavior).

fix

Update test code to use `.expect_inverse(False)` and `.expect_fluid(True)` where applicable, or adapt to the new `bool` argument for `expect_inverse`.

affects: >=1.2.0

deprecatedThe `ui.Chat().set_user_message()` method has been deprecated.

fix

Use the new `ui.Chat().update_user_input()` method instead, which provides similar functionality and more flexibility.

affects: >=1.1.0

gotchaShiny applications, by default, sanitize error messages when deployed to prevent sensitive information leakage. This can make debugging deployed applications challenging.

fix

To view full error messages for debugging purposes, set `sanitize_errors=False` in the `App` constructor: `app = App(app_ui, server, sanitize_errors=False)`.

affects: All versions

gotchaStarting with v1.6.0, Shiny includes OpenTelemetry integration. The `SHINY_OTEL_COLLECT` environment variable controls the default collection level (e.g., 'none', 'session'). If not explicitly set, 'session' level telemetry might be collected.

fix

Set the `SHINY_OTEL_COLLECT` environment variable to `'none'` if you wish to disable all Shiny-specific telemetry collection for sensitive operations or to reduce overhead.

affects: >=1.6.0

gotchaIf an output in a Shiny app fails to render or shows a 'Missing output' error, it's often due to an attempt to read a non-existent input ID or an error within the `@render` function.

fix

Double-check input IDs for typos. If an error occurs within a `@render` function, the full Python stack trace will be available in the console where `shiny run` was executed. Debug the `@render` function's logic.

affects: All versions

Errors

Common errors & fixes

Error: An error has occurred. Check your logs or contact the app author for clarification.

This is Shiny's default sanitized error message for deployed applications, hiding the underlying Python exception for security reasons.

fix

Run the application locally (`shiny run app.py --reload`) to see the full stack trace, or disable error sanitization in the `App` constructor: `app = App(app_ui, server, sanitize_errors=False)`.

Output not appearing (e.g., a blank space where a plot or text should be) or 'Missing output' message.

The output function (`@render.text`, `@render.plot`, etc.) is trying to access an input ID that does not exist or is misspelled. Alternatively, there might be a runtime error within the render function.

fix

Verify that the `id` argument in `ui.output_*` matches the name of the decorated function in `server`. Ensure that `input.some_id()` refers to an existing `ui.input_some_id` component. Check the console for any Python exceptions or tracebacks.

TypeError: 'ReactiveValue' object is not callable

Attempting to access a reactive value (like `input.some_id`) without calling it as a function (`input.some_id()`) within a reactive context.

fix

Always append `()` when reading the value of an `input` or `reactive.value` within `@reactive.effect`, `@render.*`, or `@reactive.calc` functions, e.g., `input.slider_val()` instead of `input.slider_val`.

Upgrade

Version history

1.6.3latest on PyPI · released Jun 1, 2026

Audit

Dependencies

pythonrequiredRequires Python 3.10 or newer.

websocketsrequiredShiny requires websockets>=13.0 for core functionality, with compatibility for >=14.0 introduced in v1.2.1.

Agent activity

25 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/posit-dev/py-shiny ↗

packagehttps://pypi.org/project/shiny/ ↗

homepagehttps://shiny.posit.co ↗

docshttps://shiny.posit.co/py/ ↗