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Calypso IDE

Getting started

Calypso is a code editor for Android that you can use entirely from your phone. This page gets you from a fresh install to running your first program.

1. Install Calypso

Install the Calypso APK on your Android device. On first launch you’ll land on the home screen with a file explorer and an editor.

2. Create a file

  1. Open the file explorer (the side panel).

  2. Create a new file — for example hello.py or hello.js.

  3. Type some code:

    print("Hello from Calypso!")

3. Run it

Tap Run. The Output panel opens at the bottom and shows your program’s output live.

  • Python runs via Pyodide (Python compiled to WebAssembly).
  • JavaScript runs in a sandboxed WebView.

Both run on-device with zero setup — this is Tier 1, the default path.

4. Import a package (no install needed)

You can use many libraries without installing anything:

// JavaScript — bare imports are rewritten to esm.sh automatically
import { camelCase } from "lodash-es";
console.log(camelCase("hello world"));
# Python — pure-Python wheels are fetched via micropip on first use
import emoji
print(emoji.emojize("Calypso is here :rocket:"))

5. Create a real web project

With Termux set up, Calypso can scaffold full frontend projects from the project switcher:

  1. Open the project switcher.
  2. Choose New Project.
  3. Pick a framework such as React, Vue, Svelte, or Angular.
  4. Choose the available options, such as JavaScript or TypeScript. For supported Vite templates, you can also enable Tailwind CSS.
  5. Create the project.

Calypso runs the scaffold and dependency install through Termux, then opens the new folder in the editor. These are normal framework projects with normal source files, config files, package.json, and Git support.

You can also choose Clone in the project switcher, paste a Git URL, and clone an existing repository into ~/CalypsoProjects. If your clipboard already contains a Git URL, Calypso pre-fills it. Folder names are checked before clone so you do not accidentally overwrite an existing project.

To manage projects later, open the project switcher and use the ... menu on a project row. You can rename a project, delete a project, or remove an old external folder from the recent list.

6. Try the AI assistant

Calypso has a built-in AI assistant. Add an API key (Anthropic, DeepSeek, or OpenAI) in Settings → AI Assistant, then:

  • Select code and tap the ✨ AI button to Explain, Fix, or Improve it.
  • Open AI chat to ask about your code — optionally attaching the open file or letting Calypso search the project for the relevant files.
  • Switch on the agent to let it explore your project and make edits — you review each change as a diff before it’s applied.

Your key is stored only on your device. See AI assistant for the full guide.

What’s next?

  • Some things the on-device sandbox can’t do (native packages, a real shell, npm install with binaries). See What works where to understand the boundary.
  • To get a full local toolchain, set up Termux.
  • Want AI that understands and edits your project? See AI assistant.
  • Want real autocomplete, hover, diagnostics and go-to-definition? See IntelliSense.
  • Working with a repo? See the Git workflow.