CLAUDE.md - BlitzWallet

Project Overview

BlitzWallet is a self-custodial Bitcoin Lightning wallet built with React Native (0.81.4) and Expo (~54.0). It targets iOS and Android, written in TypeScript/JavaScript.

Commands

yarn start              # Start Metro bundler
yarn android            # Run on Android device/emulator
yarn ios                # Run on iOS simulator
yarn test               # Run Jest tests
yarn lint               # Run ESLint
yarn apkBuild           # Build release APK
yarn apkBuild:clean     # Clean + build release APK
yarn playstoreBuild     # Build AAB for Play Store
yarn android:clean      # Clean + run Android

Requires Node >= 20. Uses Yarn as package manager.

Project Structure

app/
  components/           # Login/onboarding components
  constants/            # Theme, icons, regex patterns, app constants
  functions/            # Core business logic
    CustomElements/     # Reusable UI components (buttons, modals, QR codes)
    boltz/              # Atomic swap functionality
    breezLiquid/        # Liquid Network integration
    spark/              # Spark SDK integration
    sendBitcoin/        # Send payment logic
    receiveBitcoin/     # Receive payment logic
    lnurl/              # LNURL protocol handling
    nwc/                # Nostr Wallet Connect
    pos/                # Point of Sale
    contacts/           # Contact management
  hooks/                # Custom React hooks
  screens/              # Screen components
    createAccount/      # Onboarding flow (PIN, mnemonic, restore)
    inAccount/          # Main app screens (send, receive, settings, etc.)
context-store/          # React Context providers (30+ contexts)
navigation/             # React Navigation setup (stack, tabs, drawer)
db/                     # Database layer (Firebase, SQLite, AsyncStorage)
locales/                # i18n translations (en, es, fr, de, it, pt-BR, ru, sv, ko)
patches/                # Yarn dependency patches
__tests__/              # Jest test files

Code Conventions

Prettier: single quotes, trailing commas (all), no parens on single arrow params
ESLint: @react-native preset, no-undef enforced (error), inline styles allowed
State management: React Context API (not Redux) - contexts live in context-store/
Navigation: React Navigation v7 (native-stack, bottom-tabs, drawer)
Globals available: BigInt, Buffer, btoa, atob, TextDecoder, TextEncoder

Key Technologies

Lightning/Bitcoin: Spark SDK, Breez SDK (Liquid), Boltz (atomic swaps), LNURL, bolt11
Blockchain: liquidjs-lib, ethers (Rootstock), noble/secp256k1, BIP32/BIP39
Nostr: nostr-tools, Nostr Wallet Connect (NWC)
Firebase: Auth, Firestore, Cloud Functions, Messaging (FCM), Crashlytics
Local storage: expo-sqlite, AsyncStorage, expo-secure-store
UI: lucide-react-native (icons), lottie-react-native (animations), react-native-reanimated

1. Think Before Coding

Don't assume. Don't hide confusion. Surface tradeoffs.

Before implementing:

State your assumptions explicitly. If uncertain, ask.
If multiple interpretations exist, present them - don't pick silently.
If a simpler approach exists, say so. Push back when warranted.
If something is unclear, stop. Name what's confusing. Ask.

2. Simplicity First

Minimum code that solves the problem. Nothing speculative.

No features beyond what was asked.
No abstractions for single-use code.
No "flexibility" or "configurability" that wasn't requested.
No error handling for impossible scenarios.
If you write 200 lines and it could be 50, rewrite it.

Ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify.

3. Surgical Changes

Touch only what you must. Clean up only your own mess.

When editing existing code:

Don't "improve" adjacent code, comments, or formatting.
Don't refactor things that aren't broken.
Match existing style, even if you'd do it differently.
If you notice unrelated dead code, mention it - don't delete it.

When your changes create orphans:

Remove imports/variables/functions that YOUR changes made unused.
Don't remove pre-existing dead code unless asked.

The test: Every changed line should trace directly to the user's request.

4. Goal-Driven Execution

Define success criteria. Loop until verified.

Transform tasks into verifiable goals:

"Add validation" → "Write tests for invalid inputs, then make them pass"
"Fix the bug" → "Write a test that reproduces it, then make it pass"
"Refactor X" → "Ensure tests pass before and after"

For multi-step tasks, state a brief plan:

1. [Step] → verify: [check]
2. [Step] → verify: [check]
3. [Step] → verify: [check]

Strong success criteria let you loop independently. Weak criteria ("make it work") require constant clarification.

These guidelines are working if: fewer unnecessary changes in diffs, fewer rewrites due to overcomplication, and clarifying questions come before implementation rather than after mistakes.

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