feat: add DOGE, XRP, ADA, BNB, USDT token support

- Add derivation for DOGE (BIP44 coin type 3)
- Add derivation for XRP (coin type 144, Ripple base58)
- Add derivation for ADA/Cardano (CIP-1852, bech32)
- Add derivation for BNB (EVM-compatible)
- Add USDT_ETH, USDT_POL, USDT_SOL token chains
- Create DERIVABLE_CHAINS single source of truth
- Add /api/web-wallet/supported-chains endpoint
- Simplify ChainSelector to use DERIVABLE_CHAINS
- Add 48 comprehensive tests for all chains
- Update getMissingChains to fetch from API
- Add USDT contract addresses for balance fetching

Total: 15 chains now supported (was 8)

Author: ralyodio

src/app/api/web-wallet/supported-chains/route.ts

@@ -0,0 +1,21 @@
+import { NextResponse } from 'next/server';
+import { DERIVABLE_CHAINS, DERIVABLE_CHAIN_INFO } from '@/lib/web-wallet/keys';
+
+/**
+ * GET /api/web-wallet/supported-chains
+ * 
+ * Returns the list of chains that can be derived from a BIP39 mnemonic.
+ * This is the single source of truth for what chains the web wallet supports.
+ * 
+ * Response:
+ * {
+ *   chains: ['BTC', 'BCH', ...],
+ *   chainInfo: { BTC: { name: 'Bitcoin', symbol: 'BTC' }, ... }
+ * }
+ */
+export async function GET() {
+  return NextResponse.json({
+    chains: DERIVABLE_CHAINS,
+    chainInfo: DERIVABLE_CHAIN_INFO,
+  });
+}

src/app/web-wallet/create/page.tsx

@@ -9,15 +9,12 @@ import { SeedDisplay } from '@/components/web-wallet/SeedDisplay';
 import { ChainMultiSelect } from '@/components/web-wallet/ChainSelector';
 import { checkPasswordStrength } from '@/lib/web-wallet/client-crypto';
 import { downloadEncryptedSeedPhrase } from '@/lib/web-wallet/seedphrase-backup';
+import { DERIVABLE_CHAINS } from '@/lib/web-wallet/keys';
 
 type Step = 'password' | 'seed' | 'verify';
 
-const DEFAULT_CHAINS = [
-  'BTC', 'BCH', 'ETH', 'POL', 'SOL',
-  'DOGE', 'XRP', 'ADA', 'BNB',
-  'USDT', 'USDC',
-  'USDC_ETH', 'USDC_POL', 'USDC_SOL',
-];
+// Default to all derivable chains
+const DEFAULT_CHAINS = [...DERIVABLE_CHAINS];
 
 export default function CreateWalletPage() {
   const router = useRouter();

src/app/web-wallet/import/page.tsx

@@ -9,13 +9,10 @@ import { SeedInput } from '@/components/web-wallet/SeedInput';
 import { ChainMultiSelect } from '@/components/web-wallet/ChainSelector';
 import { checkPasswordStrength } from '@/lib/web-wallet/client-crypto';
 import { downloadEncryptedSeedPhrase } from '@/lib/web-wallet/seedphrase-backup';
+import { DERIVABLE_CHAINS } from '@/lib/web-wallet/keys';
 
-const DEFAULT_CHAINS = [
-  'BTC', 'BCH', 'ETH', 'POL', 'SOL',
-  'DOGE', 'XRP', 'ADA', 'BNB',
-  'USDT', 'USDC',
-  'USDC_ETH', 'USDC_POL', 'USDC_SOL',
-];
+// Default to all derivable chains
+const DEFAULT_CHAINS = [...DERIVABLE_CHAINS];
 
 export default function ImportWalletPage() {
   const router = useRouter();

src/components/web-wallet/ChainSelector.tsx

@@ -1,24 +1,15 @@
 'use client';
 
-const ALL_CHAINS = [
-  { id: 'BTC', name: 'Bitcoin', symbol: 'BTC' },
-  { id: 'BCH', name: 'Bitcoin Cash', symbol: 'BCH' },
-  { id: 'ETH', name: 'Ethereum', symbol: 'ETH' },
-  { id: 'POL', name: 'Polygon', symbol: 'POL' },
-  { id: 'SOL', name: 'Solana', symbol: 'SOL' },
-  { id: 'DOGE', name: 'Dogecoin', symbol: 'DOGE' },
-  { id: 'XRP', name: 'Ripple', symbol: 'XRP' },
-  { id: 'ADA', name: 'Cardano', symbol: 'ADA' },
-  { id: 'BNB', name: 'BNB Chain', symbol: 'BNB' },
-  { id: 'USDT', name: 'Tether', symbol: 'USDT' },
-  { id: 'USDC', name: 'USD Coin', symbol: 'USDC' },
-  { id: 'USDC_ETH', name: 'USDC (Ethereum)', symbol: 'USDC' },
-  { id: 'USDC_POL', name: 'USDC (Polygon)', symbol: 'USDC' },
-  { id: 'USDC_SOL', name: 'USDC (Solana)', symbol: 'USDC' },
-  { id: 'USDT_ETH', name: 'USDT (Ethereum)', symbol: 'USDT' },
-  { id: 'USDT_POL', name: 'USDT (Polygon)', symbol: 'USDT' },
-  { id: 'USDT_SOL', name: 'USDT (Solana)', symbol: 'USDT' },
-] as const;
+import { DERIVABLE_CHAINS, DERIVABLE_CHAIN_INFO, type DerivableChain } from '@/lib/web-wallet/keys';
+
+/**
+ * Build chain list from the single source of truth
+ */
+const CHAIN_LIST = DERIVABLE_CHAINS.map((id) => ({
+  id,
+  name: DERIVABLE_CHAIN_INFO[id].name,
+  symbol: DERIVABLE_CHAIN_INFO[id].symbol,
+}));
 
 interface BalanceInfo {
   balance: string;
@@ -43,8 +34,8 @@ export function ChainSelector({
   balances,
 }: ChainSelectorProps) {
   const available = chains
-    ? ALL_CHAINS.filter((c) => chains.includes(c.id))
-    : ALL_CHAINS;
+    ? CHAIN_LIST.filter((c) => chains.includes(c.id))
+    : CHAIN_LIST;
 
   // Format balance for display
   const formatBalance = (chainId: string): string => {
@@ -111,7 +102,7 @@ export function ChainMultiSelect({
         </label>
       )}
       <div className="grid grid-cols-1 min-[400px]:grid-cols-2 gap-2">
-        {ALL_CHAINS.map((chain) => {
+        {CHAIN_LIST.map((chain) => {
           const selected = value.includes(chain.id);
           return (
             <button

src/components/web-wallet/__tests__/ChainSelector.test.tsx

@@ -11,7 +11,7 @@ describe('ChainSelector', () => {
 
     // Should have "Select chain" + 17 chain options
     const options = screen.getAllByRole('option');
-    expect(options.length).toBe(18); // 1 placeholder + 17 chains
+    expect(options.length).toBe(16); // 1 placeholder + 15 derivable chains
   });
 
   it('should render with label', () => {

src/lib/wallet-sdk/wallet.ts

@@ -76,8 +76,8 @@ export class Wallet {
     const chains: WalletChain[] = options.chains || [
       'BTC', 'BCH', 'ETH', 'POL', 'SOL',
       'DOGE', 'XRP', 'ADA', 'BNB',
-      'USDT', 'USDC',
       'USDC_ETH', 'USDC_POL', 'USDC_SOL',
+      'USDT_ETH', 'USDT_POL', 'USDT_SOL',
     ];
     const mnemonic = generateMnemonic(options.words || 12);
     const bundle = await deriveWalletBundle(mnemonic, chains);
@@ -132,11 +132,12 @@ export class Wallet {
     }
 
     const client = new WalletAPIClient(options);
-    // Only include chains with implemented key derivation
-    // DOGE, XRP, ADA, BNB, USDT, USDC key derivation not yet implemented
+    // Default to all derivable chains
     const chains: WalletChain[] = options.chains || [
       'BTC', 'BCH', 'ETH', 'POL', 'SOL',
+      'DOGE', 'XRP', 'ADA', 'BNB',
       'USDC_ETH', 'USDC_POL', 'USDC_SOL',
+      'USDT_ETH', 'USDT_POL', 'USDT_SOL',
     ];
     const bundle = await deriveWalletBundle(mnemonic, chains);
 
@@ -322,7 +323,9 @@ export class Wallet {
     // Default chains that should exist
     const defaultChains: WalletChain[] = targetChains || [
       'BTC', 'BCH', 'ETH', 'POL', 'SOL',
+      'DOGE', 'XRP', 'ADA', 'BNB',
       'USDC_ETH', 'USDC_POL', 'USDC_SOL',
+      'USDT_ETH', 'USDT_POL', 'USDT_SOL',
     ];
 
     // Get current addresses
@@ -360,15 +363,35 @@ export class Wallet {
   async getMissingChains(
     targetChains?: WalletChain[]
   ): Promise<WalletChain[]> {
-    const defaultChains: WalletChain[] = targetChains || [
-      'BTC', 'BCH', 'ETH', 'POL', 'SOL',
-      'USDC_ETH', 'USDC_POL', 'USDC_SOL',
-    ];
+    // Dynamically fetch current supported chains from the server
+    // This ensures old wallets see newly added chains
+    let supportedChains: WalletChain[];
+    
+    if (targetChains) {
+      supportedChains = targetChains;
+    } else {
+      try {
+        // Fetch from API to get latest supported chains
+        const resp = await this.client.request<{ chains: string[] }>({
+          method: 'GET',
+          path: '/api/web-wallet/supported-chains',
+        });
+        supportedChains = (resp.chains || []) as WalletChain[];
+      } catch {
+        // Fallback to hardcoded list if API fails
+        supportedChains = [
+          'BTC', 'BCH', 'ETH', 'POL', 'SOL',
+          'DOGE', 'XRP', 'ADA', 'BNB',
+          'USDC_ETH', 'USDC_POL', 'USDC_SOL',
+          'USDT_ETH', 'USDT_POL', 'USDT_SOL',
+        ];
+      }
+    }
 
     const currentAddresses = await this.getAddresses();
     const existingChains = new Set(currentAddresses.map((a) => a.chain));
 
-    return defaultChains.filter((c) => !existingChains.has(c));
+    return supportedChains.filter((c) => !existingChains.has(c));
   }
 
   // ── Balances ──

src/lib/web-wallet/balance.ts

@@ -63,12 +63,16 @@ const USDC_CONTRACTS: Record<string, string> = {
 // USDT contract addresses (ERC-20 compatible)
 const USDT_CONTRACTS: Record<string, string> = {
   USDT_ETH: '0xdAC17F958D2ee523a2206206994597C13D831ec7',
+  USDT_POL: '0xc2132D05D31c914a87C6611C10748AEb04B58e8F', // USDT on Polygon
   USDT_BNB: '0x55d398326f99059fF775485246999027B3197955',
 };
 
 // USDC on Solana (SPL token mint)
 const USDC_SOL_MINT = 'EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v';
 
+// USDT on Solana (SPL token mint)
+const USDT_SOL_MINT = 'Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB';
+
 // USDC/USDT have 6 decimals on all chains
 const USDC_DECIMALS = 6;
 const USDT_DECIMALS = 6;
@@ -436,17 +440,20 @@ export async function fetchBalance(address: string, chain: WalletChain): Promise
       return fetchADABalance(address);
 
     // USDC variants
-    case 'USDC':
     case 'USDC_ETH':
       return fetchERC20Balance(address, USDC_CONTRACTS.USDC_ETH, rpc.ETH, USDC_DECIMALS);
     case 'USDC_POL':
       return fetchERC20Balance(address, USDC_CONTRACTS.USDC_POL, rpc.POL, USDC_DECIMALS);
     case 'USDC_SOL':
       return fetchSPLTokenBalance(address, USDC_SOL_MINT, rpc.SOL, USDC_DECIMALS);
 
-    // USDT (defaults to ETH)
-    case 'USDT':
+    // USDT variants
+    case 'USDT_ETH':
       return fetchERC20Balance(address, USDT_CONTRACTS.USDT_ETH, rpc.ETH, USDT_DECIMALS);
+    case 'USDT_POL':
+      return fetchERC20Balance(address, USDT_CONTRACTS.USDT_POL, rpc.POL, USDT_DECIMALS);
+    case 'USDT_SOL':
+      return fetchSPLTokenBalance(address, USDT_SOL_MINT, rpc.SOL, USDT_DECIMALS);
 
     default:
       throw new Error(`Unsupported chain: ${chain}`);

src/lib/web-wallet/identity.ts

@@ -11,15 +11,15 @@ import { secp256k1 } from '@noble/curves/secp256k1';
 export type WalletChain =
   | 'BTC' | 'BCH' | 'ETH' | 'POL' | 'SOL'
   | 'DOGE' | 'XRP' | 'ADA' | 'BNB'
-  | 'USDT' | 'USDC'
-  | 'USDC_ETH' | 'USDC_POL' | 'USDC_SOL';
+  | 'USDC_ETH' | 'USDC_POL' | 'USDC_SOL'
+  | 'USDT_ETH' | 'USDT_POL' | 'USDT_SOL';
 
 /** All valid chain values */
 export const VALID_CHAINS: WalletChain[] = [
   'BTC', 'BCH', 'ETH', 'POL', 'SOL',
   'DOGE', 'XRP', 'ADA', 'BNB',
-  'USDT', 'USDC',
   'USDC_ETH', 'USDC_POL', 'USDC_SOL',
+  'USDT_ETH', 'USDT_POL', 'USDT_SOL',
 ];
 
 /** BIP44 derivation path patterns per chain */
@@ -31,13 +31,14 @@ export const DERIVATION_PATHS: Record<string, string> = {
   SOL: "m/44'/501'",
   DOGE: "m/44'/3'/0'/0",
   XRP: "m/44'/144'/0'/0",
-  ADA: "m/1852'/1815'/0'/0",
+  ADA: "m/1852'/1815'/0'/0'",
   BNB: "m/44'/60'/0'/0",
-  USDT: "m/44'/60'/0'/0",
-  USDC: "m/44'/60'/0'/0",
   USDC_ETH: "m/44'/60'/0'/0",
   USDC_POL: "m/44'/60'/0'/0",
   USDC_SOL: "m/44'/501'",
+  USDT_ETH: "m/44'/60'/0'/0",
+  USDT_POL: "m/44'/60'/0'/0",
+  USDT_SOL: "m/44'/501'",
 };
 
 /**
@@ -99,14 +100,15 @@ export function validateAddress(address: string, chain: WalletChain): boolean {
     case 'ETH':
     case 'POL':
     case 'BNB':
-    case 'USDT':
-    case 'USDC':
     case 'USDC_ETH':
     case 'USDC_POL':
+    case 'USDT_ETH':
+    case 'USDT_POL':
       // EVM address: 0x followed by 40 hex chars
       return /^0x[0-9a-fA-F]{40}$/.test(address);
     case 'SOL':
     case 'USDC_SOL':
+    case 'USDT_SOL':
       // Solana: base58 encoded, 32-44 chars
       return /^[1-9A-HJ-NP-Za-km-z]{32,44}$/.test(address);
     case 'DOGE':
@@ -132,11 +134,16 @@ export function validateDerivationPath(path: string, chain: WalletChain): boolea
   const basePath = DERIVATION_PATHS[chain];
   if (!basePath) return false;
 
-  if (chain === 'SOL' || chain === 'USDC_SOL') {
+  if (chain === 'SOL' || chain === 'USDC_SOL' || chain === 'USDT_SOL') {
     // Solana uses: m/44'/501'/n'/0'
     return /^m\/44'\/501'\/\d+'\/0'$/.test(path);
   }
 
+  if (chain === 'ADA') {
+    // Cardano CIP-1852 (all hardened for Ed25519): m/1852'/1815'/account'/role'/index'
+    return /^m\/1852'\/1815'\/\d+'\/\d+'\/\d+'$/.test(path);
+  }
+
   // BTC/BCH/ETH/POL: m/44'/coinType'/0'/0/n
   const escapedBase = basePath.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
   const regex = new RegExp(`^${escapedBase}/\\d+$`);
@@ -155,27 +162,28 @@ export function isValidChain(chain: string): chain is WalletChain {
  */
 export function buildDerivationPath(chain: WalletChain, index: number): string {
   switch (chain) {
-    case 'SOL':
-    case 'USDC_SOL':
-      return `m/44'/501'/${index}'/0'`;
     case 'BTC':
       return `m/44'/0'/0'/0/${index}`;
     case 'BCH':
       return `m/44'/145'/0'/0/${index}`;
     case 'ETH':
     case 'POL':
     case 'BNB':
-    case 'USDT':
-    case 'USDC':
     case 'USDC_ETH':
     case 'USDC_POL':
+    case 'USDT_ETH':
+    case 'USDT_POL':
       return `m/44'/60'/0'/0/${index}`;
+    case 'SOL':
+    case 'USDC_SOL':
+    case 'USDT_SOL':
+      return `m/44'/501'/${index}'/0'`;
     case 'DOGE':
       return `m/44'/3'/0'/0/${index}`;
     case 'XRP':
       return `m/44'/144'/0'/0/${index}`;
     case 'ADA':
-      return `m/1852'/1815'/0'/0/${index}`;
+      return `m/1852'/1815'/0'/0'/${index}'`;
     default:
       throw new Error(`Unsupported chain: ${chain}`);
   }