feat: add MegaETH chain support

.env

@@ -156,6 +156,7 @@ VITE_ARBITRUM_NOVA_NODE_URL=https://api.arbitrum-nova.shapeshift.com/api/v1/json
 VITE_BASE_NODE_URL=https://api.base.shapeshift.com/api/v1/jsonrpc
 VITE_MONAD_NODE_URL=https://rpc.monad.xyz
 VITE_PLASMA_NODE_URL=https://rpc.plasma.to
+VITE_MEGAETH_NODE_URL=https://mainnet.megaeth.com/rpc
 VITE_THORCHAIN_NODE_URL=https://api.thorchain.shapeshift.com/lcd
 VITE_MAYACHAIN_NODE_URL=https://api.mayachain.shapeshift.com/lcd
 VITE_SOLANA_NODE_URL=https://api.solana.shapeshift.com/api/v1/jsonrpc
@@ -303,4 +304,5 @@ VITE_FEATURE_MONAD=true
 VITE_FEATURE_PLASMA=true
 VITE_HYPEREVM_NODE_URL=https://rpc.hyperliquid.xyz/evm
 VITE_FEATURE_HYPEREVM=true
+VITE_FEATURE_MEGAETH=false
 VITE_FEATURE_NEAR=false

.env.development

@@ -64,6 +64,7 @@ VITE_BASE_NODE_URL=https://dev-api.base.shapeshift.com/api/v1/jsonrpc
 VITE_MONAD_NODE_URL=https://rpc.monad.xyz
 VITE_PLASMA_NODE_URL=https://rpc.plasma.to
 VITE_HYPEREVM_NODE_URL=https://rpc.hyperliquid.xyz/evm
+VITE_MEGAETH_NODE_URL=https://mainnet.megaeth.com/rpc
 # Swap me back to 9R as-needed
 # VITE_THORCHAIN_NODE_URL=https://thornode.ninerealms.com
 VITE_THORCHAIN_NODE_URL=https://dev-api.thorchain.shapeshift.com/lcd
@@ -92,4 +93,5 @@ VITE_FEATURE_NOTIFICATIONS_WEBSERVICES=true
 
 VITE_FEATURE_WC_DIRECT_CONNECTION=true
 VITE_FEATURE_CETUS_SWAP=true
+VITE_FEATURE_MEGAETH=true
 VITE_FEATURE_NEAR=true

.yarnrc.yml

@@ -2,7 +2,7 @@ nodeLinker: node-modules
 
 npmAuthToken: "${NPM_AUTH-fallback}"
 
-npmRegistryServer: "https://registry.npmjs.org"
+npmRegistryServer: "http://127.0.0.1:4873"
 
 plugins:
   - path: .yarn/plugins/@yarnpkg/plugin-interactive-tools.cjs

CLAUDE.md

@@ -3,6 +3,7 @@
 ## Global Programming Rules
 
 ### Code Quality & Style
+
 - Look for opportunities to use existing code rather than creating new code
 - Follow existing code conventions in each file/project
 - Use existing libraries and utilities already present in the codebase
@@ -19,6 +20,7 @@
 - When function parameters are unused due to interface requirements, refactor the interface or implementation to remove them rather than prefixing with underscore
 
 ### Security & Best Practices
+
 - Never expose, log, or commit secrets, API keys, or credentials
 - Validate all inputs, especially user inputs
 - Use parameterized queries to prevent SQL injection
@@ -27,34 +29,39 @@
 - Use HTTPS and secure communication protocols
 
 ### Error Handling
+
 - Handle errors gracefully with meaningful messages
 - Don't silently catch and ignore exceptions
 - Log errors appropriately for debugging
 - Provide fallback behavior when possible
 - Use proper HTTP status codes in APIs
 
 ### Performance
+
 - Avoid premature optimization, but be mindful of performance
 - Use appropriate data structures for the task
 - Minimize database queries and API calls
 - Implement proper caching strategies
 - Optimize images and assets for web delivery
 
 ### Testing
+
 - Write tests for critical business logic
 - Test edge cases and error conditions
 - Use descriptive test names that explain behavior
 - Keep tests isolated and independent
 - Mock external dependencies appropriately
 
 ### Documentation & Communication
+
 - Never add code comments unless explicitly requested
 - When modifying code, do not add comments that reference previous implementations or explain what changed. Comments should only describe the current logic and functionality.
 - Write clear commit messages explaining the "why"
 - Use meaningful names for branches, variables, and functions
 - Keep README files updated with setup and usage instructions
 
 ### Rule Management
+
 - When user says "add that to the project rules": take previous guidance, form a rule, add to project-specific section in CLAUDE.md
 - When user says "add that to the global rules": take previous guidance, form a rule, add to global rules section in CLAUDE.md
 
@@ -63,13 +70,15 @@
 ## Project-Specific Rules: ShapeShift
 
 ### Project Overview
+
 - **Project**: Decentralized crypto exchange platform
 - **Main branch**: `develop` (not main/master)
 - **Package manager**: yarn
 - **State management**: Redux Toolkit with redux-persist
 - **Architecture**: Plugin-based for blockchain support
 
 ### Code Quality & Standards
+
 - Always run `yarn lint --fix` and `yarn type-check` after making changes
 - Keep changes surgical where possible - minimize changes to make code reviews easier
 - Make targeted, focused modifications rather than broad refactors unless specifically requested
@@ -79,42 +88,65 @@
 - Avoid `let` variable assignments - prefer `const` with inline IIFE switch statements or extract to functions for conditional logic
 - For static JSX icon elements (e.g., `<TbCopy />`) that don't depend on state/props, define them as constants outside the component to avoid re-renders instead of using useMemo
 
+### Code Style & Formatting
+
+**Prettier/ESLint formatting rules (follow these to avoid lint changes):**
+
+- Use **single quotes** for strings (both JS and JSX)
+- **No semicolons** at end of statements
+- 100 character line width
+- Trailing commas everywhere
+- Arrow functions: avoid parens for single parameter (`x => x` not `(x) => x`)
+- Use `===` not `==` (eqeqeq rule)
+- Object shorthand (`{ foo }` not `{ foo: foo }`)
+- No default exports (use named exports: `export const Foo` not `export default Foo`)
+  - Exception: Allowed in `*.stories.*` and test mock data files
+- Type imports: Use `import type` for types (`import type { Foo } from './foo'`)
+- Prefer top-level type imports over inline type imports
+
 ### Git & Version Control
+
 - Never commit changes unless explicitly requested
 - When creating commits, follow the Git Safety Protocol (see session notes)
 - Main branch is `develop` - use this for PRs
 - Branch naming: Use descriptive names (e.g., `feat_gridplus`, `fix_wallet_connect`)
 
 ### UI/UX Standards
+
 - Account for light/dark mode using `useColorModeValue` hook
 - Account for responsive mobile designs in all UI components
 - When applying styles, use the existing standards and conventions of the codebase
 - Use Chakra UI components and conventions
 
 ### Internationalization (i18n)
+
 - All copy/text must use translation keys - never hardcode strings
 - Add English copy to `src/assets/translations/en/main.json` (find appropriate section)
 - Ignore other language translation files - only update English
 - Use the translation hook: `useTranslate()` from `react-polyglot`
 
 ### Feature Flags
+
 - Feature flags are stored in Redux state under `preferences.featureFlags`
 - Feature flags are NOT persisted between sessions (blacklisted in redux-persist)
 - Default values always come from environment variables prefixed with `VITE_FEATURE_`
 
 **To add a new feature flag:**
+
 1. Add to `FeatureFlags` type in `src/state/slices/preferencesSlice/preferencesSlice.ts`
 2. Add environment variable validation in `src/config.ts` (e.g., `VITE_FEATURE_MY_FLAG: bool({ default: false })`)
 3. Add to initial state in `preferencesSlice.ts` (e.g., `MyFlag: getConfig().VITE_FEATURE_MY_FLAG`)
 4. Add to test mock in `src/test/mocks/store.ts`
 5. Set appropriate values in `.env`, `.env.development`, and `.env.production`
 
 **Usage:**
+
 - Use `useFeatureFlag('FlagName')` hook to access feature flag values in components
 - The `/flags` route provides a hidden UI for toggling feature flags at runtime (click settings modal header 5 times)
 - Use `.env.development` for dev-only features and `.env.production` for prod settings
 
 ### Redux State Management
+
 - Uses Redux Toolkit with createSlice
 - State is persisted with redux-persist (localforage)
 - Migrations are required when changing persisted state structure (see `src/state/migrations/`)
@@ -126,6 +158,7 @@
   5. Export selectors from slice using `selectors` property
 
 ### Type Definitions
+
 - Prefer `type` over `interface` for type definitions
 - Use strict typing - avoid `any`
 - Use `Nominal` types for domain identifiers (e.g., `WalletId`, `AccountId`)
@@ -134,17 +167,20 @@
 ### Common Patterns
 
 **Selectors:**
+
 - Use `createDeepEqualOutputSelector` from `@/state/selector-utils` for deep equality checks
 - Use `createCachedSelector` from `re-reselect` for parameterized selectors
 - Export selectors from slice using inline `selectors` property
 
 **Components:**
+
 - Use `useAppSelector` for Redux state
 - Use `useAppDispatch` for Redux actions
 - Memoize expensive computations with `useMemo`
 - Memoize callbacks with `useCallback`
 
 **Wallet Integration:**
+
 - Wallets are managed via `WalletProvider` context
 - Each wallet has unique `walletId` (e.g., `metamask:0x123`, `ledger:ABC`)
 - Portfolio state is filtered by active `walletId`

headers/csps/chains/megaeth.ts

@@ -0,0 +1,10 @@
+import { loadEnv } from 'vite'
+
+import type { Csp } from '../../types'
+
+const mode = process.env.MODE ?? process.env.NODE_ENV ?? 'development'
+const env = loadEnv(mode, process.cwd(), '')
+
+export const csp: Csp = {
+  'connect-src': [env.VITE_MEGAETH_NODE_URL],
+}

headers/csps/index.ts

@@ -16,6 +16,7 @@ import { csp as gnosis } from './chains/gnosis'
 import { csp as hyperevm } from './chains/hyperevm'
 import { csp as litecoin } from './chains/litecoin'
 import { csp as mayachain } from './chains/mayachain'
+import { csp as megaeth } from './chains/megaeth'
 import { csp as monad } from './chains/monad'
 import { csp as near } from './chains/near'
 import { csp as optimism } from './chains/optimism'
@@ -106,6 +107,7 @@ export const csps = [
   gnosis,
   hyperevm,
   litecoin,
+  megaeth,
   optimism,
   polygon,
   solana,

package.json

@@ -217,7 +217,7 @@
     "use-long-press": "^3.3.0",
     "uuid": "^9.0.0",
     "vaul": "^1.1.2",
-    "viem": "2.40.3",
+    "viem": "2.43.5",
     "wagmi": "^2.9.2",
     "web-vitals": "^2.1.4",
     "wouter": "^3.6.0"

packages/caip/src/constants.ts

@@ -19,6 +19,7 @@ export const baseAssetId: AssetId = 'eip155:8453/slip44:60'
 export const monadAssetId: AssetId = 'eip155:143/slip44:60'
 export const hyperEvmAssetId: AssetId = 'eip155:999/slip44:60'
 export const plasmaAssetId: AssetId = 'eip155:9745/slip44:60'
+export const megaethAssetId: AssetId = 'eip155:4326/slip44:60' // TODO: MegaETH Mainnet - Switch from testnet when whitelisted
 export const solAssetId: AssetId = 'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp/slip44:501'
 export const wrappedSolAssetId: AssetId =
   'solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp/token:So11111111111111111111111111111111111111112'
@@ -78,6 +79,7 @@ export const baseChainId: ChainId = 'eip155:8453'
 export const monadChainId: ChainId = 'eip155:143'
 export const hyperEvmChainId: ChainId = 'eip155:999'
 export const plasmaChainId: ChainId = 'eip155:9745'
+export const megaethChainId: ChainId = 'eip155:4326' // TODO: MegaETH Mainnet (Frontier) - Switch from testnet when whitelisted
 
 export const cosmosChainId: ChainId = 'cosmos:cosmoshub-4'
 export const thorchainChainId: ChainId = 'cosmos:thorchain-1'
@@ -127,6 +129,7 @@ export const CHAIN_REFERENCE = {
   MonadMainnet: '143', // https://docs.monad.xyz/developer-essentials/network-information
   HyperEvmMainnet: '999', // https://chainlist.org/chain/999
   PlasmaMainnet: '9745', // https://chainlist.org/chain/9745
+  MegaEthMainnet: '4326', // https://docs.megaeth.com/frontier - TODO: Switch from testnet when whitelisted
   SolanaMainnet: '5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp', // https://namespaces.chainagnostic.org/solana/caip2
   TronMainnet: '0x2b6653dc', // https://developers.tron.network/docs/networks
   SuiMainnet: '35834a8a', // First 8 chars of SUI mainnet genesis hash
@@ -169,6 +172,7 @@ export const ASSET_REFERENCE = {
   Monad: '60', // evm chain which uses ethereum derivation path as common practice
   HyperEvm: '60', // evm chain which uses ethereum derivation path as common practice
   Plasma: '60', // evm chain which uses ethereum derivation path as common practice
+  MegaEth: '60', // evm chain which uses ethereum derivation path as common practice
   Solana: '501',
   Tron: '195',
   Sui: '784',
@@ -197,6 +201,7 @@ export const VALID_CHAIN_IDS: ValidChainMap = Object.freeze({
     CHAIN_REFERENCE.MonadMainnet,
     CHAIN_REFERENCE.HyperEvmMainnet,
     CHAIN_REFERENCE.PlasmaMainnet,
+    CHAIN_REFERENCE.MegaEthMainnet,
   ],
   [CHAIN_NAMESPACE.CosmosSdk]: [
     CHAIN_REFERENCE.CosmosHubMainnet,
@@ -250,6 +255,7 @@ export const FEE_ASSET_IDS = [
   arbitrumNovaAssetId,
   baseAssetId,
   monadAssetId,
+  megaethAssetId,
   solAssetId,
   tronAssetId,
   suiAssetId,

packages/chain-adapters/package.json

@@ -51,7 +51,7 @@
     "multicoin-address-validator": "^0.5.12",
     "node-polyglot": "^2.4.0",
     "p-queue": "^8.0.1",
-    "viem": "^2.40.3"
+    "viem": "2.43.5"
   },
   "devDependencies": {
     "@types/bs58check": "^2.1.0",

packages/chain-adapters/src/evm/EvmBaseAdapter.ts

@@ -16,6 +16,7 @@ import {
   supportsETH,
   supportsGnosis,
   supportsHyperEvm,
+  supportsMegaEth,
   supportsMonad,
   supportsOptimism,
   supportsPlasma,
@@ -82,6 +83,7 @@ export const evmChainIds = [
   KnownChainIds.MonadMainnet,
   KnownChainIds.HyperEvmMainnet,
   KnownChainIds.PlasmaMainnet,
+  KnownChainIds.MegaEthMainnet,
 ] as const
 
 export type EvmChainAdapter = EvmBaseAdapter<EvmChainId>
@@ -151,7 +153,12 @@ export abstract class EvmBaseAdapter<T extends EvmChainId> implements IChainAdap
 
   getBip44Params({ accountNumber }: GetBip44ParamsInput): Bip44Params {
     if (accountNumber < 0) throw new Error('accountNumber must be >= 0')
-    return { ...this.rootBip44Params, accountNumber, isChange: false, addressIndex: 0 }
+    return {
+      ...this.rootBip44Params,
+      accountNumber,
+      isChange: false,
+      addressIndex: 0,
+    }
   }
 
   protected assertSupportsChain(
@@ -184,6 +191,8 @@ export abstract class EvmBaseAdapter<T extends EvmChainId> implements IChainAdap
           return supportsHyperEvm(wallet)
         case Number(fromChainId(KnownChainIds.PlasmaMainnet).chainReference):
           return supportsPlasma(wallet)
+        case Number(fromChainId(KnownChainIds.MegaEthMainnet).chainReference):
+          return supportsMegaEth(wallet)
         default:
           return false
       }
@@ -276,6 +285,11 @@ export abstract class EvmBaseAdapter<T extends EvmChainId> implements IChainAdap
         symbol: 'XPL',
         explorer: 'https://plasmascan.to',
       },
+      [KnownChainIds.MegaEthMainnet]: {
+        name: 'Ether',
+        symbol: 'ETH',
+        explorer: 'https://megaeth.blockscout.com',
+      },
     }[this.chainId]
 
     try {
@@ -665,7 +679,10 @@ export abstract class EvmBaseAdapter<T extends EvmChainId> implements IChainAdap
     const bip44Params = this.getBip44Params({ accountNumber })
     const subscriptionId = toRootDerivationPath(bip44Params)
 
-    this.providers.ws.unsubscribeTxs(subscriptionId, { topic: 'txs', addresses: [] })
+    this.providers.ws.unsubscribeTxs(subscriptionId, {
+      topic: 'txs',
+      addresses: [],
+    })
   }
 
   closeTxs(): void {

packages/chain-adapters/src/evm/index.ts

@@ -17,3 +17,4 @@ export * as base from './base'
 export * as monad from './monad'
 export * as hyperevm from './hyperevm'
 export * as plasma from './plasma'
+export * as megaeth from './megaeth'