Flet Studio

Flet Studio is a browser-based editor for writing, running, saving and sharing Flet apps. Your Python code runs entirely in the browser via Pyodide — there is no Flet account required to try it, and no local install required to run something someone else built and shared with you.

Why it exists

Flet Studio started as a tool we wanted for ourselves and kept being useful for things we hadn't planned. In rough order:

• A playground that saves your work. Unlike a transient REPL or a paste-and-run sandbox, projects in Studio persist across sessions and across devices once you sign in.
• A way to share small apps via a link. Send a colleague or someone on the Flet team a URL and they can open, run, and read the code without setting anything up. Handy for bug reports, design sketches, and "look at this control".
• A gallery of Flet examples that you can actually edit. Browse examples, open one, tweak it, fork it into your own project — same editor, same runtime.
• A zero-commitment way to try Flet. Before pip install flet, before reading the getting-started docs, you can write a few lines and see them run.
• A dogfooding project. Studio's UI is itself a Flet app. Building it surfaces gaps in Flet and ideas for improvements, which feed back into the framework.
• The base UI for future Flet services. Cloud packaging and publishing are on the roadmap — Studio is the surface those will plug into. (Today: editor only.)

How it works

• Your code runs in the browser. Flet Studio uses Pyodide — CPython compiled to WebAssembly — to execute your Python directly in the browser tab. Nothing you write is sent to a server to be run.
• There is a Flet Studio backend, but it's only for the IDE itself — file storage, authentication, accounts, project metadata. Your app's Python code never executes on our servers; it executes client-side, in your browser, in Pyodide.
• The rendering engine is the same one flet publish and flet build web produce. What you see in Studio is what you'd get from a published Flet static site — same controls, same layout, same web runtime.

Limitations

Studio inherits the constraints of running Python in the browser. Most of these are covered in more detail in the static website publishing docs:

• Pure-Python packages and Pyodide-built wheels only. Most of the Python ecosystem works, but packages with C/Rust extensions need a Pyodide build. See the Pyodide built-in packages list. Source-only sdists (no wheel) cannot be installed.
• Single browser thread. No real threads. Long blocking work freezes the UI — prefer async I/O.
• Browser sandbox. No access to your local filesystem, no shell, no access to local hardware that isn't exposed by the browser.
• Performance. Pyodide is roughly 3×–5× slower than CPython for CPU-bound code.
• Cold start. The first load fetches the Python runtime and any wheels you import, so initial load is slower than a native install. Subsequent loads are cached.

Does it replace local Flet development?

No.

Studio is for trying Flet, prototyping small apps, sharing snippets, learning, and showing off ideas. For everything else — desktop and mobile builds, native packages, real multi-file projects, your favorite IDE and debugger, the full Python ecosystem without the Pyodide constraints above — install Flet locally and use flet run and flet build. See installation when you're ready to make the jump.