How to Build Mobile Apps with Claude Code

Why mobile is different from web work in Claude Code

Claude Code treats a mobile repo the same way it treats any project. It reads files, edits them, runs commands, and shows diffs. The difference is the feedback loop and the surface area.

On the web the agent can often reason about a page from the markup alone. On mobile the output only exists after a build lands on a simulator or device. There is a compile step, a native toolchain, and two platforms that disagree about layout, permissions, navigation, and fonts. The agent cannot see the rendered screen unless you show it.

So mobile work with Claude Code is a tighter loop of describe, build, run, screenshot, correct. Your job is to keep that loop fast and to give the agent the context it cannot infer: which framework, which version, which platforms, and what your existing components look like. Get those four things right and the agent behaves like a strong mobile developer who already read your codebase.

Set up a mobile project the agent can drive

Start in a real project folder and make the toolchain runnable from the terminal, because that is the only place Claude Code can act. Then write a CLAUDE.md that removes the guesswork.

# React Native / Expo
npx create-expo-app@latest my-app
cd my-app && npx expo start

# Flutter
flutter create my_app
cd my_app && flutter run

Iterate on UI with a screenshot loop

Layout is the part where the agent is blind, so you close the gap by feeding it pixels. Keep a simulator running the whole session. When you ask for a screen, let the agent write the components, then build and run it, capture the simulator screenshot, and paste that image back into the conversation.

The agent reads the screenshot and adjusts. "The header overlaps the notch, move content below the safe area" becomes a concrete fix once it can see the overlap. This loop is far more reliable than describing a layout in words. On iOS, watch for safe area insets, dynamic type, and the home indicator. On Android, watch for the status bar, back gesture, and elevation shadows that do not translate from iOS design.

Work one screen at a time. Approve the diff, run it, screenshot, correct. A focused loop on a single screen produces better output than asking for five screens at once and debugging a pile of layout errors together.

Handle the platform gotchas that break agent output

Mobile has sharp edges that a general model does not always respect. Name them up front and the agent stops making the same class of mistake.

• Navigation: React Navigation, Expo Router, and Flutter's Navigator all differ by major version. Pin the version in CLAUDE.md so the agent stops mixing patterns.
• Permissions: camera, location, and notifications need platform specific declarations in Info.plist and AndroidManifest.xml. Ask the agent to update both, and verify it did.
• Native dependencies: a library that needs a pod install or a Gradle change will not just work after npm install. Tell the agent when a dependency has a native step.
• Async storage and secure storage: the correct package changes between framework versions, and this is a common place the agent picks a deprecated one.

The underlying issue is version drift. Framework APIs move quickly, and the model's built in knowledge trails the current release. That mismatch is where most of your rework and wasted tokens come from on mobile, because the agent confidently writes an API that no longer exists and you spend a round trip correcting it.

Cut rework by grounding the agent in current APIs

The fix for version drift is retrieval. Instead of hoping the model remembers the current React Native, Expo SDK, or Flutter surface, give the agent a place to look it up.

RDK is built for this. You index the material the agent keeps getting wrong as encrypted private chunks: your framework's official docs for the version you actually ship, the release notes that mark what changed, and your own component library so the agent reuses your Button and Screen primitives instead of inventing new ones. The agent searches those chunks before it calls the model, so it emits the correct current API and your real component names rather than a plausible hallucination.

The payoff is fewer correction rounds. Private vault retrieval alone answers 40 to 65 percent of everyday queries, and the public network adds another 15 to 20 percent, leaving the model as fallback for the rest. On mobile, where a single wrong navigation import can cost several build and fix cycles, retrieving the settled answer instead of regenerating it removes the most expensive failure mode. You do not need this to ship a first screen. Reach for it once the same framework mistakes keep reappearing across sessions.