Guide · updated 16 October 2026

How to vibe code an Android app on your phone, offline

By Yossi Oknin, developer of CodeTalk

What you need

Step by step

1. Pick a model that fits your RAM. Open the Models tab. CodeTalk reads your free memory and checks the CPU for ARM dotprod support, then marks one model "Recommended for this device". Download it.
2. Let it set up the build tools once. Before the first Android build, CodeTalk installs JDK 17 (about 180 MB) and the Android SDK into its own folder. Stay on Wi-Fi for this step.
3. Create an Android project. In the Projects tab, tap New, choose Android, and give it a name and a package name. CodeTalk scaffolds a Gradle project with a working MainActivity.kt.
4. Describe the app. In the Agent tab, type or tap the mic and say it in one or two sentences. Name the screen parts you want: "a habit tracker with a checkbox for each day and a reset button".
5. Approve the plan. The model answers with a small JSON plan: the files it will write and any libraries. CodeTalk asks "Plan ready with 1 file(s) to write. Proceed?" Tap Approve, or Cancel and rephrase.
6. Build, fix and install. CodeTalk runs Gradle. If the compiler complains, it reads the error and tries a fix, up to 3 attempts, and can look the error up on the web when you are online. Then it installs the debug APK and launches it.

Best local LLM for Android coding, by RAM

These are the rules CodeTalk uses to recommend a model. "Free RAM" is the memory Android reports as available, which is lower than the phone's total.

Qwen 2.5 Coder 1.5B (about 1.1 GB) is also offered for low-RAM phones; it handles simple apps only. The 7B models run without dotprod too, but CodeTalk warns that they will be very slow. On a phone that generates under 3 tokens per second, CodeTalk raises the model timeout from 5 to 10 minutes.

Prompts that work well with a small model

A 3B model on a phone does best with one screen and named parts. These prompts hit CodeTalk's templates and component catalog, so the output is reliable.

• a snake gameUses the tested Snake template (swipe controls, score, game over).
• a tic tac toe gameTic-Tac-Toe template.
• a dice rollerDice roller template.
• a notes appNotepad template.
• a countdown timerTimer template. "stopwatch" gets its own.
• a settings screen with a dark mode switch and a volume sliderSwitch and slider come from the component catalog; the model writes the rest.
• a sign-up form with a name text field and an agree checkboxText field and checkbox from the catalog.

The other templates are Calculator, Todo list, Flashlight, Counter, Stopwatch and Flappy Bird. Templates and the catalog apply to local models; cloud models write everything themselves.

Limits worth knowing

• Small plans. With a local model, an Android plan is 1 or 2 Kotlin files. Build bigger apps one feature at a time: "now add a history list".
• Debug APKs. CodeTalk builds debug APKs. For a Play Store release, push to GitHub or Bitbucket, or export a ZIP, and sign a release build.
• New libraries need internet. A Maven library named in the plan is added to build.gradle.kts and downloaded at build time.
• Bigger brains are optional. For complex apps, connect Claude, OpenAI, Grok or OpenRouter with your own key, or an Ollama or LM Studio server on your network.

When a build keeps failing

• After 3 fix attempts CodeTalk stops and shows "Still failing" with the last error. Rephrase with more detail and run it again.
• Tap Undo in the Agent toolbar to restore every file from .codetalk/backups/.
• Open the Terminal tab to run git status or look at files, or open a file in the editor and fix one line yourself.
• Switch to a larger model in the Models tab if your RAM allows it.

Questions