CodeDroid
A pocket IDE for Android that runs code offline
- Year
- 2025–2026
- Category
- Digital Products
- Status
- Active open-source build
01 — Summary
A development environment built natively for Android: a multi-tab editor, on-device Python and JavaScript runtimes, cloud compilation for other languages and a coding-friendly keyboard row.
02 — The challenge
Most Android code editors only highlight syntax; they cannot run anything. The few that can depend on remote compile servers, which fail on trains and in rural areas.
Standard phone keyboards hide brackets, semicolons, pipes and tabs behind nested menus, which makes coding tiring.
03 — Our approach
A CodeMirror-based editor with highlighting and folding across 18 languages. Python runs on the device through Chaquopy and JavaScript through Rhino, with no network needed.
Compiled languages such as C, C++, Java and Go run through the Piston API when online. A toolbar above the keyboard gives one-tap access to brackets, symbols and indentation.
Built for: Students and developers who want to write and run code on a phone or tablet, including on commutes and in low-connectivity areas.
04 — How it works
- 01
Open a project
Create or open files through Android’s storage framework.
- 02
Write comfortably
Auto-indent, bracket pairing and the symbol toolbar.
- 03
Run offline
Python and JavaScript execute on the phone itself.
- 04
Compile when online
C, C++, Java and Go are sent to Piston for compilation.
- 05
Inspect and preview
Read output in the terminal or preview web pages in a WebView.
05 — Build notes
- Chaquopy bindings that run CPython 3 on the device.
- Mozilla Rhino for in-memory JavaScript.
- A custom keyboard accessory row with haptic feedback.
- Tuned to run on budget phones with 3 GB of RAM.
Stack
- Android SDK
- Java / Kotlin
- Chaquopy
- Rhino
- CodeMirror
- Piston API
- Languages
- 18
- Offline runtimes
- Python, JavaScript
- Licence
- GPLv3
06 — Why it matters
An affordable Android phone becomes a working, offline-capable place to learn and practise programming.
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