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tempestroid

Build native Android apps in typed Python.

You write one declarative, fully typed widget tree (a Pydantic IR). A renderer-agnostic reconciler diffs it into patches. Two leaf renderers apply those patches: Qt for the desktop simulator and Jetpack Compose for the device. The runtime is async-first, with an Expo-style dev loop (hot reload in the simulator and LAN code-push on the device).

A framework, not a web service

There is no FastAPI, SQLAlchemy, Redis, or HTTP layering here. The focus is the typed UI tree and the reconciler. See the design plan for the full design and the phase roadmap.

🤖 Read the project with your AI (llms.txt)

This site publishes two files following the llmstxt.org convention so you can hand your AI assistant (Claude, ChatGPT, Cursor, etc.) the whole project as a reference — no server, no MCP:

  • /llms.txt — a lean index (summary + links to every page). Use it when your AI can follow the links.
  • /llms-full.txt — the entire documentation concatenated into one Markdown file. Use it to paste/attach everything at once when your AI cannot browse.

How to use: paste the URL (or the content) of llms-full.txt into your assistant's context and ask it to use it as the tempestroid reference. The files are regenerated on every docs deploy, so they are always current.

Why

  • Typed end to end. Style model, widget primitives, events, and the Python↔Kotlin boundary contract are all Pydantic v2 / fully typed. pyright runs in strict mode.
  • One tree, two targets. The reconciler is pure data-in → patches-out. All platform divergence is confined to the two Style translators (Qt and Compose).
  • Async-first. Event handlers and lifecycle hooks may be sync or async; Python runs on a background asyncio loop, never the UI thread.
  • Fast inner loop. tempest dev watches your file and hot-reloads the Qt simulator on save — no device or emulator needed for UI work.

How it works

   view(app) ──build──▶  Node tree (IR)
                              │
                            diff           pure, renderer-agnostic
                              ▼
                          [ Patch ]        Insert / Remove / Update / Reorder / Replace
                         ╱          ╲
                  Qt renderer      Compose renderer
                  (simulator)        (device)
  1. view(app) -> Widget builds a declarative widget tree from current state.
  2. build lowers it to a Node IR; diff compares old vs. new and emits a minimal Patch list.
  3. A renderer applies patches to live widgets. State changes coalesce into one rebuild per tick.

Next steps