An AI mobile app builder for native phone apps

When you build a phone app with AI in Shipmunk, you get a native app, not a website in a phone-shaped frame. Screens are React Native views, not web pages, and the app opens in Expo Go. This page covers what you get, how you try it, what the builder checks, and where the limits are today.

What you get when you build a phone app with AI

On Home, Shipmunk opens on "Build a phone app". You write what you want in plain words, for example a phone app where a running club logs each run and sees a weekly leaderboard. It helps to say who uses it on their phone, the one flow that must work, and which phone features it needs, such as the camera, location or reminders.

The result is a full app, not just screens:

• A native React Native app on Expo, with screens built from React Native and React Native Paper (Material 3) components.
• An API backend in FastAPI with its own contract, which the app reads its data from.
• Checks for the app and the API that the builder writes and runs before it calls a round done.

Every app made this way avoids web views. A required check fails the build if the app depends on a WebView or on native code that Expo Go cannot run.

How the AI mobile app builder works

1. Describe it

   Pick "Build a phone app" and write a sentence or two about the app and who uses it.

2. Shipmunk plans it

   The plan sets out each screen, the API it talks to, and the checks that prove the main flow works. Anything Expo Go cannot do is listed as out of scope, with the nearest alternative, and no screen offers it.

3. It builds and checks each round

   The builder works in its own container. It runs a type check, the app's tests, and a check that every dependency runs in Expo Go. A browser check renders a web version of the app and takes screenshots of the phone view.

4. It opens the round on a phone

   When a round passes its required checks and a phone is free, Shipmunk opens it in Expo Go on a hosted Android phone and reads the log. If the app crashes at start, the next round gets the error to fix.

For the full flow from sentence to finished app, see how Shipmunk builds and tests an app.

The phone check: catching start-up crashes

An app can pass its tests and still crash the moment it opens on a phone. A missing native module or a bad import is enough. So a mobile build has one more required check, "Runs on a phone".

Here is what it does. The round's app starts as a short-lived preview. A hosted Android phone opens it in Expo Go. Shipmunk then reads the phone's log. The check fails if the app's JavaScript crashes, or if the app does not start within 90 seconds. When it fails, the fix round gets the error messages and the stack trace mapped to the app's own files, so the builder knows where to look.

The phone check needs a free phone. If none is free in time, or the phone fails for a reason that is not the app's fault, the step says the check was skipped rather than pretending it passed.

Try the app from your computer or your phone

Each mobile build's page has a Phone pane with two ways in.

A cloud phone session lasts 15 minutes, and the pane shows how long is left. When it ends, start again. Between sessions, Shipmunk closes the preview apps on the phone and clears their data, before anyone else gets it. If every cloud phone is busy, the pane points you to your own phone instead.

What phone features work

Expo Go runs only the native code it ships with, so Shipmunk sticks to that set. Within it, an app can use:

• The camera, the photo picker and the media library.
• Location and maps.
• Local reminders scheduled on the phone.
• Storage on the phone, including secure storage for sensitive values and SQLite.
• Haptics, sharing, the calendar, contacts, sensors, audio and video.

The builder also follows phone conventions. Apps use a bottom tab bar with at most five tabs, or a stack of screens. The main flow works with one thumb. Light and dark mode follow the phone's setting. The Android back button closes a dialog before it leaves a screen. Lists pull to refresh, dates use native pickers, and forms stay clear of the keyboard.

Limits today

Shipmunk is in closed beta, and the phone side has clear limits:

• Expo Go only. Your app runs inside Expo Go. Shipmunk does not publish to app stores or produce an installable app file for a mobile build.
• No remote push notifications. Expo Go does not support them. Local reminders work.
• Android in the cloud. The cloud phones and the phone check are Android.
• Time-limited previews. A cloud phone session lasts 15 minutes. A preview lasts at most an hour from when you open it, and only while the build is under seven days old. Change something to get a fresh one.
• Credits. Builds and previews use credits, charged for the AI and compute they use.

Previews end on their own. Read more on how Shipmunk keeps builds and previews isolated. Apps that talk to outside services are tested in the Sandbox, with stand-in versions of tools. Other questions are answered in the Shipmunk FAQ.