NiceGUI: Web-based user interfaces with Python. The nice way.

New features and enhancements

• Introduce ui.skip_link for keyboard-accessibility skip links (WCAG 2.4.1 "Bypass Blocks") (#5790 by @evnchn, @falkoschindler)
• Add per-line hover tooltips to ui.codemirror via a new line_tooltips property (with optional line_tooltip_html) (#5992 by @Jepson2k, @falkoschindler, @evnchn)
• Add a ui.plotly run_plot_method() helper (mirroring run_grid_method/run_chart_method) with a Plotly.extendTraces demo for appending data without re-sending the full figure (#2660, #6060 by @evnchn, @falkoschindler)
• Improve the error message when storing a non-JSON-serializable value in app.storage, pointing at the offending key path and the underlying type instead of an internal class name (#6044, #6050 by @NichtJens, @falkoschindler, @evnchn)

Bugfixes

• Fix dropped app.native.window_args, app.native.settings and app.native.start_args when the spawned window process can't re-execute the main module (e.g. console-scripts, python -m, PyInstaller); unpicklable values now emit a one-time warning instead of being silently dropped (#6082, #6093 by @VFLins, @falkoschindler, @evnchn)

• Fix blank ui.aggrid when flex columns use the infinite row model; auto_size_columns becomes a tri-state bool | None defaulting to None (skip autoSizeStrategy when columns use flex) (#5087, #6080 by @davetapley, @evnchn, @falkoschindler)

• Fix Event.emitted() returning None instead of the emitted arguments, adding an opt-in expect_args parameter to Event.subscribe() (#6077, #6078 by @falkoschindler, @evnchn)

• Fix the ui.sub_pages 404 sad-face persisting after client-side navigation when the page is first loaded at an unknown URL (#6069, #6071 by @evnchn, @falkoschindler)

  Note: Apps that relied on the styled sad-face overlay appearing on ui.sub_pages 404s now see only the inline 404: sub page X not found label inside their own chrome. The HTTP 404 status and the show_404=False escape hatch are unchanged.

• Replace the misleading "remove the main guard" reload error for python -m <pkg> with a targeted message naming the package and the working alternatives (#181, #3769, #5280, #5939, #6066, #6068 by @NichtJens, @evnchn, @falkoschindler)

• Fix Client has been deleted warning spam on reload when scene objects are mutated after await (#6058, #6059 by @codingpaula, @evnchn, @falkoschindler)

  Note: Element.update(), run_method() and get_computed_prop() now stay silent only for the disconnect/reload race; using an element after an explicit element.delete() emits a one-shot warning with a stack trace.

Documentation

• Improve the Markdown documentation served to AI agents: serve Markdown to known agent user-agents sending a wildcard Accept, emit heading prefixes while skipping decorative HTML and demo previews, and add aria-label/child-content labels to button Markdown (#6007, #6052, #6053, #6054 by @evnchn, @falkoschindler, @HosseyNJF)
• Fill llms.md gaps in the element surface vs. ui.* exports (#6048, #6051 by @evnchn, @falkoschindler)
• Document how to keep ui.plotly responsive with large datasets by passing NumPy arrays / pandas Series instead of Python lists (#3340, #6095 by @TsaiTung-Chen, @python-and-novella, @mohsenminaei, @krashdifferent, @eddie3ruff, @buiapp, @falkoschindler, @evnchn)
• Fix bad Cumulative Layout Shift (CLS) on the documentation homepage (#6087, #6089 by @evnchn, @falkoschindler)

Testing

• Redo: randomize test ports and directories for parallel pytest sessions, re-applying #5960 with a fix for the #6061 import-time Storage.path regression (#5960, #6061, #6075 by @falkoschindler, @evnchn)

Infrastructure

• Fix Selenium screenshot artifacts not being uploaded on test failure (#6086 by @HosseyNJF, @evnchn, @falkoschindler)

Special thanks to our top sponsors DiscoLike Inc. and Lechler GmbH ✨

and all our other sponsors and contributors for supporting this project!

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