Architecture

How QR Wallet is built inside — for the curious and developers.

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Tech Stack

Component	Technology
Mobile App	React Native + Expo
State Management	Zustand
Web3	viem, permissionless.js
Navigation	expo-router
Blockchain	ERC-4337 Account Abstraction
Infrastructure	Alchemy (RPC, Bundler, Paymaster)
Security	Biometric + Secure Enclave

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Modular Architecture

QR Wallet is built on a modular architecture — each feature is isolated in its own module with clear layers:

modules/{feature}/
├── domain/          ← Pure business logic and types
├── infrastructure/  ← API, storage, external services
├── application/     ← State management and facades
└── ui/              ← React components (UI)

Layers

Layer	Responsibility	Example
Domain	Types, interfaces, business rules	Swap.entity.ts, StakingPool
Infrastructure	API calls and external services	SwapApi.ts, AlchemyPaymaster
Application	State, UI logic, facades	useSwapFacade.ts, SponsoredTxStore
UI	Visual components	SwapScreen.tsx, buttons, cards

Import Rule

UI → Application → Domain & Infrastructure → Domain

UI never talks to Infrastructure directly — only through the Application layer. Domain is pure, with zero dependencies.

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Chain Abstraction

Working with different blockchains is unified through an abstraction layer:

┌──────────────────────────────────────┐
│            Chain Core                 │
│                                      │
│  ┌──────────┐ ┌──────┐ ┌──────────┐ │
│  │   EVM    │ │Solana│ │   Tron   │ │
│  │ Provider │ │Provid│ │ Provider │ │
│  └──────────┘ └──────┘ └──────────┘ │
│                                      │
│  ChainRegistry → ChainConfigProvider │
│                                      │
│  Unified interface for all operations│
└──────────────────────────────────────┘

• ChainRegistry — registry of all supported networks

• ChainConfigProvider — configuration and capabilities per chain

• TransactionService — unified TX sending (EVM, Solana, Tron)

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Account Abstraction Stack

┌──────────────────────────────────────────────┐
│                User                           │
│          (biometrics → signature)             │
└──────────────────┬───────────────────────────┘
                   ↓
┌──────────────────┴───────────────────────────┐
│          IAccountProvider                     │
│    Build UserOperation                        │
│    (sender, nonce, callData, initCode)        │
└──────────────────┬───────────────────────────┘
                   ↓
┌──────────────────┴───────────────────────────┐
│          IPaymaster                           │
│    Gas sponsorship                            │
│    (paymasterAndData, gas estimates)          │
└──────────────────┬───────────────────────────┘
                   ↓
┌──────────────────┴───────────────────────────┐
│          IBundler                             │
│    Submit to blockchain                       │
│    (sendUserOperation → waitForReceipt)       │
└──────────────────┬───────────────────────────┘
                   ↓
┌──────────────────┴───────────────────────────┐
│          EntryPoint (on-chain)                │
│    Validate → Execute → Pay gas               │
└──────────────────────────────────────────────┘

Three interfaces (IAccountProvider, IPaymaster, IBundler) abstract away the specific provider. Currently using Alchemy, but the architecture allows switching to any provider without changing business logic.

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Token Registry

A single registry for all tokens in the system:

// Each token is described once
{
  symbol: 'USDC',
  name: 'USD Coin',
  addresses: { base: '0x...', arbitrum: '0x...', polygon: '0x...' },
  decimals: { default: 6 },
  flags: { swappable: true, collateral: true, borrowable: true, stakable: true }
}

Modules get the tokens they need via flags:

• swappable: true → Swap tokens

• collateral: true → Borrow collateral tokens

• borrowable: true → Borrowable tokens

• stakable: true → Staking tokens

This eliminates duplication — token data is described once and used everywhere.

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18 Languages

The app is localized in 18 languages:

EN, RU, ES, FR, HI, ID, JA, KO, MS, PT, TH, TL, TR, UR, VI, ZH, AR, BN