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Flet v0.25.0 Release Announcement

· 10 min read
Feodor Fitsner
Feodor Fitsner
Flet founder and developer

Hey Flet developers, we’ve got something exciting to share — Flet 0.25.0 is officially released!

The biggest news? No more Kivy for iOS and Android packaging. No more dealing with frustrating Python binary dependencies — Flet now uses its own custom Python runtime, so your app builds are easier than ever. Plus, we’ve added loads of new features like better permissions control, faster rebuilds, and even a lightweight Linux client that skips the bloat.

Let’s dive into all the cool stuff Flet 0.25.0 has to offer! 🚀

How to upgrade​

Run the following command to upgrade Flet:

pip install 'flet[all]' --upgrade
note

[all] is an "extra" specifier which tells pip to install all flet package dependencies. See New Python packages structure section below for the explanation.

Bump flet package version to 0.25.0 (or remove it at all to use the latest) in requirements.txt or pyproject.toml.

New packaging​

Flet packaging for iOS and Android has been relying on Kivy and it was super annoying when your app depends on Python binary packages, such as Numpy or Pillow. You needed to compile those packages yourself using Kivy command line tools. It was really frustrating and even hopeless if Kivy didn't have "recipes" for some packages, like Pydantic.

Flet does not depend on Kivy anymore and uses its own Python runtime "meticulously crafted in-house".

Flet packaging implementation for iOS and Androind adheres to strict specifications defined in PEP 730 (iOS) and PEP 738 (Android) which were implemented and released in Python 3.13 (and back-ported to Python 3.12). When pypi.org supports wheel tags for iOS and Android and 3rd-party Python package maintainers start uploading their mobile packages Flet will be compatible with them and you'll be able to use them in your Flet app.

Pre-built binary packages​

flet build command for iOS and Android is now installing pre-built binary packages from https://pypi.flet.dev.

New packages can be built with creating a recipe in Mobile Forge project. For now, Flet team is authoring those recipes for you, but when the process is polished and fully-automated you'll be able to send a PR and test the compiled package right away.

If you don't yet see a package you require at https://pypi.flet.dev, you can request it in Flet discussions - Packages. Please do not request pure Python packages. Go to package's "Download files" section at https://pypi.org and make sure it contains binary platform-specific wheels.

Packaging behavior was changed too:

  • The packaging is not trying to replace flet dependency with flet-runtime, flet-embed or flet-pyodide, but install all dependencies "as is" from requirements.txt or pyproject.toml - thanks to the new Flet packages structure.
  • If the binary package for target platform is not found the packaging won't be trying to compile it from source distribution, but will fail instead with a meaningful error.

Python 3.12​

Packaged Flet app runs on Python 3.12.7 runtime on all platforms.

Permissions​

New flet build command allows granular control over permissions, features and entitlements embedded into AndroidManifest.xml, Info.plist and .entitlements files.

No more hard-coded permissions in those files!

For example, setting permissions for iOS bundle:

flet build --info-plist NSLocationWhenInUseUsageDescription="This app uses location service when in use."

or the same in pyproject.toml (read about pyproject.toml support below):

[tool.flet.ios.info] # --info-plist
NSLocationWhenInUseUsageDescription = "This app uses location service when in use."

An example of setting Android permissions and features:

flet build \
    --android-permissions android.permission.READ_EXTERNAL_STORAGE=True \
      android.permission.WRITE_EXTERNAL_STORAGE=True \
    --android-features android.hardware.location.network=False

Read more about permissions in the docs.

Control over app compilation and cleanup​

flet build command is no longer compiling app .py files into .pyc by default which allows you to defer discovery of any syntax errors in your app and complete the packaging.

You can control the compilation and cleanup with the following new options:

  • --compile-app - compile app's .py files.
  • --compile-packages - compile installed packages' .py files.
  • --cleanup-on-compile - remove unnecessary files upon successful compilation.

Signing Android bundles​

We also added new options for signing Android builds:

  • --android-signing-key-store - path to an upload keystore .jks file for Android apps.
  • --android-signing-key-store-password - Android signing store password.
  • --android-signing-key-alias - Android signing key alias. Default is "upload".
  • --android-signing-key-password - Android signing key password.

Read Build and release an Android app for more information on how to configure upload key for Android builds.

Deep linking configuration​

There is a new --deep-linking-url option to configure deep linking for iOS and Android builds. The value must be in the format <sheme>://<host>.

Faster re-builds​

Ephemeral Flutter app created by flet build command is no longer being re-created on every build in a temp directory, but cached in build/flutter directory which gives faster re-builds, improves packaging troubleshooting and does not pollute user temp directory.

You can use --clear-cache option to do a clean build though.

Split APKs per ABI​

flet build now provides the built-in --split-per-abi option to split the APKs per ABIs.

"Data" and "Temp" directories for the app​

Flet developers have been asking where to store application data, such as uploaded files, SQLite databases, etc. that are persistent across application updates.

This release introduce two environment variables that are available in your Flet apps:

  • FLET_APP_STORAGE_DATA - directory for storing application data that is preserved between app updates. That directory is already pre-created and its location depends on the platform the app is running on.
  • FLET_APP_STORAGE_TEMP - directory for temporary application files, i.e. cache. That directory is already pre-created and its location depends on the platform the app is running on.

For example, data folder path can be read in your app as:

import os

# it's `None` when running the app in web mode
data_dir = os.getenv("FLET_APP_STORAGE_DATA")
note

flet run command creates data and temp directories and sets FLET_APP_STORAGE_DATA and FLET_APP_STORAGE_TEMP to their paths.

pyproject.toml support​

It's inconvenient and bulky to carry all flet build settings as command line options.

In Flet 0.25.0 release is now possible to configure flet build, flet run, and flet publish settings in pyproject.toml!

Flet adds tool.flet section and sub-sections to pyproject.toml. Here's the minimal version of pyproject.toml you can put into root folder of your app:

[project]
name = "my_app"
version = "1.0.0"
description = "My first Flet project"
authors = [
  {name = "John Smith", email = "[email protected]"}
]
dependencies = ["flet"]

You can also generate a starting pyproject.toml (and other files) for your project with flet create command.

New Python packages structure​

We re-factored Flet Python packages and removed flet-core, flet-runtime, flet-embed orflet-pyodide packages.

The new structure avoids rewriting pip dependencies while installing flet package on various platforms. There was a problem of detecting the correct flet package to install (flet-runtime, flet-embed orflet-pyodide?) if flet was not a direct dependency in user's app.

New Flet packages:

  • flet - required for minimal Flet setup, app entry point for various platforms with core logic and controls. Installed on all platforms.
  • flet-cli - contains Flet CLI commands. Installed on desktop only.
  • flet-desktop - contains pre-built Flet "client" app binary for macOS, Windows and Linux. By default installed on macOS and Windows desktops only.
  • flet-desktop-light - contains a light-weight version (without Audio and Video controls) of Flet "client" for Linux. By default installed on Linux desktops only.
  • flet-web - contains Flet web "client" and FastAPI integration. Installed on desktop only.

Packaged Flet app contains only flet package now.

flet package extras​

flet package defines the following extras that can be specified when installing Flet with pip, uv, poetry and other package manager:

  • flet[all] - installs flet, flet-cli, flet-desktop and flet-web. Recommended for development.
  • flet[cli] - installs flet and flet-cli. Can be used in CI environment for packaging only.
  • flet[web] - installs flet and flet-web. Used for deploying Flet web apps.
  • flet[desktop] - installs flet and flet-desktop. Used for desktop-only development.

New Flet install and upgrade commands​

Starting from this release the development version of flet package should be installed with the following command:

pip install 'flet[all]'

Ugrading flet package:

pip install 'flet[all]' --upgrade
note

pip install flet still works too, but it will install flet package only and dependent packages will be installed on demand. For example, when you run any flet CLI command flet-cli will be installed, or when you run flet run command flet-desktop package will be installed.

"Light" client for Linux​

A lightweight desktop client, without Audio and Video controls, is now installed on Linux by default. It improves initial user experience as user doesn't need to immediately deal with gstreamer (audio) and mpv (video) dependencies and Flet "just works".

Once user got some Flet experience and wants to use Video and Audio controls in their application they can install gstreamer and/or mpv and replace Flet desktop with a full version.

Uninstall "light" Flet client:

pip uninstall flet-desktop-light --yes

Install full Flet desktop client:

pip install flet-desktop

New controls​

  • Mobile Ads (Banner and Interstitial) (details and example).
  • Button control (#4265) - which is just an alias for ElevatedButton control.

Breaking changes​

  • Refactor Badge Control to a Dataclass; added new badge property to all controls (#4077).

Below is how to migrate:

# before
    page.navigation_bar = ft.NavigationBar(
        destinations=[
            ft.NavigationBarDestination(
                icon_content=ft.Badge(
                    content=ft.Icon(ft.Icons.PHONE),
                    text=10,
                ),
                label="Calls",
            ),
        ]
    )

# after
    page.navigation_bar = ft.NavigationBar(
        destinations=[
            ft.NavigationBarDestination(
                  icon=ft.Icon(
                        ft.Icons.PHONE,
                        badge="10",
                    ),
                label="Calls",
            ),
        ]
    )

Other changes​

  • Added {value_length}, {max_length}, and {symbols_left} placeholders to TextField.counter_text (#4403).
  • Added --skip-flutter-doctor to build cli command (#4388).
  • WebView enhancements (#4018).
  • Map control enhancements (#3994).
  • Exposed more Theme props (#4278, #4278).
  • Exposed more properties in multiple Controls (#4105)
  • Added __contains__ methods in container-alike Controls (#4374).
  • Added a custom Markdown code theme (#4343).
  • Added barrier_color prop to dialogs (#4236).
  • Merged icon and icon_content props into icon: str | Control (#4305).
  • Migrated colors and icons variables to Enums (#4180).
  • TextField: suffix_icon, prefix_icon and icon can be Control or str (#4173).
  • Added --pyinstaller-build-args to flet pack CLI command (#4187).
  • Made SearchBar's view height adjustable; added new properties (#4039).
  • Bumped Rive version and fixed Linux app build template for rive_common.

Bug fixes​

  • Fixed Icon rotation (#4384).
  • Fixed regression in Markdown.code_theme when using MarkdownCodeTheme enum (#4373).
  • Fixed Segment and NavigationBarDestination accept only string tooltips (#4326).
  • Display informative message when date has wrong format (#4019).
  • Fixed MapConfiguration.interaction_configuration is not honoured (#3976).
  • Fixed Video.jump_to() fails with negative indexes (#4294).
  • Fixed condition in AppBar.tooltip_opacity (#4280).
  • Fixed wrong type (asyncio.Future -> concurrent.futures.Future) and handle CancelledError (#4268).
  • Fixed clicking on CupertinoContextMenuAction doesn't close context menu (#3948).
  • Fixed dropdown max_menu_height (#3974).
  • Fixed prevent button style from being modified in before_update() (#4181).
  • Fixed disabling filled buttons is not visually respected (#4090).
  • when label is set, use MainAxisSize.min for the Row (#3998).
  • Fixed NavigationBarDestination.disabled has no visual effect (#4073).
  • Fixed autofill in CupertinoTextField (#4103).
  • Linechart: jsonDecode tooltip before displaying (#4069).
  • Fixed button's bgcolor, color and elevation (#4126).
  • Fixed scrolling issues on Windows (#4145).
  • Skip running flutter doctor on windows if no_rich_output is True (#4108).
  • Fixed TextField freezes on Linux Mint #4422](https://github.com/flet-dev/flet/pull/4422)).

Conclusion​

Flet 0.25.0 is a huge release and your feedback is highly welcomed!

Upgrade to Flet 0.25.0, test your apps and let us know how you find the new features we added.

If you have any questions, please join Flet Discord server or create a new thread on Flet GitHub discussions.

Happy Flet-ing! 👾