Mojito ME — Mobile Edition

The React Native client for Mojito, Mintlayer's non-custodial wallet — "your gateway to Bitcoin DeFi."

Mojito is self-custodial by design: your keys, your coins. It holds BTC, ML, MLS-01 tokens and NFTs, generates a fresh address per transaction for privacy, encrypts client-side before anything leaves the device, and restores from a seed phrase alone. Mojito already ships as a browser extension and on the App Store and Google Play; this repository is the neo generation of the mobile app, rebuilt in React Native.

---

⚠️ Project status — pre-production

This repository is a UI implementation. It is not a working wallet.

There is no backend, no chain connectivity, and no key management. Every balance, address, transaction and account in the app is a fixture from src/data.js or src/onboarding/data.js. Specifically, and deliberately:

• The recovery phrase is a fixed demo constant, not generated entropy.
• Checksum validation on import is a stand-in, not BIP39 — see checksumOK().
• The BIP39 word list is truncated (a–cy) for the autocomplete demo.
• The "draw your own entropy" screen collects and meters real input but does not derive a key.
• Biometric prompts are simulated; no LocalAuthentication call is made.

Do not point this at real funds. Do not treat any screen here as a security control until the corresponding logic is implemented and audited.

---

What's implemented

Area	Screens
Onboarding	Welcome · Secure (biometric) · PIN set/confirm · Seed reveal · Verify backup · Import phrase · Account discovery · Draw-your-own-entropy
Wallet	Home (portfolio, balance chart, activity) · DEX (order book + ticket)
Trade	Atomic Swap (HTLC) · Bridge (Mintlayer ⇄ EVM) · Mojito Card waitlist
Flows	Send (3-step) · Receive (QR) · Settings
App	Splash · Unlock (biometric + PIN with lockout)

---

Tech stack

• Expo SDK 53 / React Native 0.79 / React 19
• NativeWind v4 (Tailwind for React Native)
• react-native-svg for icons, charts and the entropy canvas
• TypeScript, strict mode
• No navigation library — screen switching is plain state in App.tsx

Layout

App.tsx                     root shell: tabs, overlays, onboarding/lock layering
src/theme.js                design tokens; oklch→sRGB (feeds tailwind.config.js too)
src/data.js                 wallet fixtures

src/ui/                     shared component library — one file per component
  index.tsx                 barrel: re-exports only
  Btn.tsx  Card.tsx  ListRow.tsx  Sheet.tsx  TokenPicker.tsx  …
  icons.tsx                 line-icon set
  motion.tsx                animation primitives (one useLoop backs them all)
  style.ts                  gradColors · toneColor · hairlineTop
  chart.ts                  polyline maths shared by Sparkline and AreaChart

src/screens/                one screen per file
  HomeScreen.tsx  DexScreen.tsx  SwapScreen.tsx  BridgeScreen.tsx
  CardScreen.tsx  SendScreen.tsx  ReceiveScreen.tsx  SettingsScreen.tsx
  intro.tsx                 splash
  types.ts                  Nav / Sheet prop types

src/onboarding/
  index.tsx                 <Onboarding> + the screen map
  context.ts                Ctx, ScreenId, lockout constants
  UnlockScreen.tsx
  screens/                  one screen per file (Welcome, Secure, PinSet, …)
  ui/                       onboarding-only components, one file each
  data.js                   BIP39 list, demo phrase, discovery fixtures

---

Build and run

Prerequisites

• Node 20+
• iOS: full Xcode (Command Line Tools alone cannot run a simulator)
• Android: Android SDK with an AVD, or a physical device with Expo Go

Install

npm install

Run

npm start            # Metro + QR code — scan with Expo Go
npm run ios          # iOS simulator (requires full Xcode)
npm run android      # Android emulator

Physical device: install Expo Go, then scan the QR from npm start. Phone and machine must share a network — add --tunnel if they don't.

Android troubleshooting — real issues hit during development

SDK not on PATH. If adb isn't found, export your SDK location. Homebrew installs land in a non-default path:

export ANDROID_HOME=/opt/homebrew/share/android-commandlinetools   # or ~/Library/Android/sdk
export PATH="$ANDROID_HOME/platform-tools:$ANDROID_HOME/emulator:$PATH"

npm run android fails on newer emulator images. Expo launches Expo Go via monkey, which exits 251 on Android 15. Launch the deep link directly instead:

npx expo start
adb reverse tcp:8081 tcp:8081
adb shell am start -a android.intent.action.VIEW -d "exp://127.0.0.1:8081" host.exp.exponent

Fast Refresh and new named imports. Adding a new named import to a live module can throw Property 'X' doesn't exist even though the code is correct. Force a full reload:

adb shell am force-stop host.exp.exponent

The seed screen captures black. Intentional — FLAG_SECURE is applied while the recovery phrase is on screen, and released on unmount.

---

Tests and checks

npm run check        # everything CI should run: unit test + types + lint
npm run lint         # eslint only
node src/theme.test.js

npm run check runs three things:

1. src/theme.test.js — asserts the oklch→sRGB conversion against the known sRGB primaries. Every colour in the app flows through it, so it's the one piece of non-trivial logic with a runnable check. Plain node:assert, no framework.
2. tsc --noEmit — strict TypeScript.
3. eslint . — eslint-config-expo, including the react-hooks rules.

There is no UI/component test suite yet. Adding one (React Native Testing Library + jest-expo) is a welcome contribution — start with the onboarding flow, which holds the most logic. Until then, changes touching navigation or gestures should be verified on a device or simulator: a green tsc has repeatedly failed to catch runtime issues here — a modal that swallowed every touch typechecked and bundled perfectly.

---

Contributing

Contributions are welcome. This is a self-custody wallet, so the bar for anything touching keys, seed material or transaction construction is high. By participating you agree to our Code of Conduct.

Before you start

1. Open an issue before writing anything non-trivial, so two people don't build the same thing.
2. Browse src/ui/ first — one file per component, so the list of what exists is the directory listing. The component you need may already be there.

Workflow

1. Fork, branch from main (feat/…, fix/…, docs/…).
2. Make the change.
3. npm run check must pass.
4. Verify on a simulator or device if you touched UI, navigation or gestures.
5. Open a PR describing what changed and why, with screenshots for visual changes.

House rules

• Reuse before you write. src/ui/ is one file per component so you can see everything at a glance. Check it before adding one; if you need a variant, add a prop rather than a near-copy. New components go in their own file and get re-exported from src/ui/index.tsx.
• No hardcoded colours or spacing. Everything comes from src/theme.js (C, G) or Tailwind tokens. tailwind.config.js imports the same palette, so there is one source of truth.
• Text goes through <Txt>. React Native Text doesn't inherit colour; the wrapper applies the palette default.
• Mark deliberate shortcuts. A ponytail: comment naming the ceiling and the upgrade path beats a silent simplification.
• Don't let the UI claim something it doesn't do. A button that says "Copied" must have copied. If a control isn't wired yet, leave it out or disable it visibly.
• Accessibility isn't optional. Icon-only controls need accessibilityLabel; inputs need a label. The shared primitives handle most of this — use them.

---

Security

Reporting

See SECURITY.md for the full policy.

Please report security issues privately — do not open a public issue. Email security@mintlayer.org with a description, reproduction steps and an assessment of impact. We'll acknowledge receipt and keep you updated.

Encrypt anything sensitive with our PGP key — security.asc, fingerprint 8EE2 B7AC 3BA2 5D1B 3C5A BD49 0ED0 DD9A A56E BDA4. See SECURITY.md for the import and verification steps.

Bug bounty

The Mintlayer bug bounty does not apply to this repository yet.

Mojito ME is pre-production: a UI implementation with no key management, no chain connectivity and deliberately mocked cryptography (see Project status). Findings against mock data, placeholder checksums or simulated biometrics are out of scope and not eligible for a reward.

The bounty becomes valid for this repository when it ships to production, at which point this section will be updated with the scope and terms. Reports are still welcome in the meantime — they're just not paid.

---

License

MIT — see LICENSE.