Codex App Android

🤯 What Is This?

OpenAI's Codex CLI is a terminal-based AI coding agent that reads codebases, writes code, and executes commands. It's incredible — but desktop-only.

We put it on Android. This APK bundles an entire Linux environment, installs Node.js and the native Rust Codex binary, wires up a Vue.js web UI, and serves it all through a WebView. Full AI coding agent in your pocket.

💬 Chat Interface

Full conversational UI with streaming responses, reasoning visibility, model selection, and multi-thread sessions.

🦀 Native Binary

73MB Rust binary (aarch64-musl) running natively — not emulated. Full codex app-server with JSON-RPC.

🐧 Embedded Linux

Complete Termux-derived userland with sh, apt, Node.js, npm, SSL certs — extracted from APK assets.

🌐 DNS Proxy Bridge

Node.js CONNECT proxy bridges Android's DNS to the musl binary. No /etc/resolv.conf needed.

🔓 Full Auto-Approval

Pre-configured with approval_policy = "never" and danger-full-access sandbox mode.

🔋 Background Execution

Foreground service + battery optimization exemption keeps the server alive when you switch apps.

🏗️ Architecture

User taps Send
  → 🖥️ Vue ThreadComposer → useDesktopState → codexGateway
    → 📡 POST /codex-api/rpc { method: "turn/start" }
      → 🔌 Express bridge → JSON-RPC stdin → codex app-server
        → 🦀 Native Rust binary → HTTPS via proxy → OpenAI API
        → 📤 stdout JSON-RPC notifications (streaming)
      → 📺 SSE EventSource → live typing in WebView

Four layers: Vue frontend → Express server → JSON-RPC stdio bridge → Native Rust binary. All running locally on your phone at 127.0.0.1:18923.

⚡ Quick Start

# 🔨 Clone the repo
git clone https://github.com/friuns2/codex-app-android.git
cd codex-app-android

# 📦 Install deps & build frontend
npm install && npm run build

# 🐧 Download Termux bootstrap (one-time)
cd android && bash scripts/download-bootstrap.sh

# 📱 Bundle, build, install, launch
bash scripts/build-server-bundle.sh && ./gradlew assembleDebug \
  && adb install -r app/build/outputs/apk/debug/app-debug.apk \
  && adb shell am start -n com.codex.mobile/.MainActivity
  

🧩 Startup Sequence

1

Battery & Service

Request Doze exemption, start foreground service with persistent notification.

2

Bootstrap Extraction

Extract Termux bootstrap zip into app's private storage. Fix hardcoded paths.

3

Node.js Installation

Download and extract Node.js 24 .deb packages from Termux repos via apt-get.

4

Codex CLI + Web UI

Extract pre-built server bundle from APK. Install native Rust binary from npm registry.

5

Config & Proxy

Write full-access config. Start Node.js CONNECT proxy for DNS/TLS bridging.

6

Auth & Launch

OAuth via browser → health check → start Express server → load WebView.

📊 Tech Stack

Layer	Technology	Version
🤖 AI Engine	OpenAI Codex CLI	0.104.0
🦀 Native Binary	Rust (musl, aarch64)	—
🟢 Runtime	Node.js (Termux)	24.13.0
🌐 Frontend	Vue.js 3 + Vite + Tailwind	3.x
🔌 Backend	Express + JSON-RPC bridge	—
📱 Android	Kotlin + WebView	2.1.0

🤖 Codex App Android