Alchemy RPC support is added

.gitignore

@@ -29,3 +29,6 @@ build/
 
 # Finder (MacOS) folder config
 .DS_Store
+
+# Env files
+.env

README.md

@@ -238,6 +238,16 @@ The mnemonic option supports hierarchical deterministic (HD) wallet derivation:
 - Store mnemonics securely - they provide access to all derived accounts
 - Consider using different account indices for different purposes
 
+
+#### Alchemy configuration
+
+```bash
+export ALCHEMY_API_KEY="your-alchemy-api-key-here"
+```
+
+If you use [Alchemy](https://alchemy.com) and want to use its RPC endpoints, you can specify app's API key.
+Otherwise, default JSON RPC rate-limited endpoints will be used. 
+
 #### API Keys (For ABI Fetching)
 
 ```bash

src/core/alchemy.ts

@@ -0,0 +1,96 @@
+// Alchemy RPC URL mapping by chain
+// Reference: https://www.alchemy.com/docs/reference/node-supported-chains
+
+import {
+  mainnet,
+  optimism,
+  arbitrum,
+  arbitrumNova,
+  base,
+  polygon,
+  polygonZkEvm,
+  avalanche,
+  bsc,
+  zksync,
+  linea,
+  celo,
+  scroll,
+  mantle,
+  blast,
+  metis,
+  moonbeam,
+  flowMainnet,
+  sepolia,
+  holesky,
+  optimismSepolia,
+  arbitrumSepolia,
+  baseSepolia,
+  polygonAmoy,
+  avalancheFuji,
+  bscTestnet,
+  zksyncSepoliaTestnet,
+  lineaSepolia,
+  celoAlfajores,
+  scrollSepolia,
+  mantleSepoliaTestnet,
+  blastSepolia,
+  metisSepolia,
+  flowTestnet,
+  type Chain,
+} from 'viem/chains';
+
+export const alchemyNetworkMap = new Map<Chain, string>([
+  // Mainnets
+  [mainnet, 'eth-mainnet'],
+  [optimism, 'opt-mainnet'],
+  [arbitrum, 'arb-mainnet'],
+  [arbitrumNova, 'arbnova-mainnet'],
+  [base, 'base-mainnet'],
+  [polygon, 'polygon-mainnet'],
+  [polygonZkEvm, 'polygonzkevm-mainnet'],
+  [avalanche, 'avax-mainnet'],
+  [bsc, 'bnb-mainnet'],
+  [zksync, 'zksync-mainnet'],
+  [linea, 'linea-mainnet'],
+  [celo, 'celo-mainnet'],
+  [scroll, 'scroll-mainnet'],
+  [mantle, 'mantle-mainnet'],
+  [blast, 'blast-mainnet'],
+  [metis, 'metis-mainnet'],
+  [moonbeam, 'moonbeam-mainnet'],
+  [flowMainnet, 'flow-mainnet'],
+
+  // Testnets
+  [sepolia, 'eth-sepolia'],
+  [holesky, 'eth-holesky'],
+  [optimismSepolia, 'opt-sepolia'],
+  [arbitrumSepolia, 'arb-sepolia'],
+  [baseSepolia, 'base-sepolia'],
+  [polygonAmoy, 'polygon-amoy'],
+  [avalancheFuji, 'avax-fuji'],
+  [bscTestnet, 'bnb-testnet'],
+  [zksyncSepoliaTestnet, 'zksync-sepolia'],
+  [lineaSepolia, 'linea-sepolia'],
+  [celoAlfajores, 'celo-alfajores'],
+  [scrollSepolia, 'scroll-sepolia'],
+  [mantleSepoliaTestnet, 'mantle-sepolia'],
+  [blastSepolia, 'blast-sepolia'],
+  [metisSepolia, 'metis-sepolia'],
+  [flowTestnet, 'flow-testnet'],
+]);
+
+const alchemyNetworkByChainId: Record<number, string> = Object.fromEntries(
+  [...alchemyNetworkMap.entries()].map(([chain, network]) => [chain.id, network])
+);
+
+export function getAlchemyRpcUrl(chainId: number, apiKey: string): string | null {
+  const network = alchemyNetworkByChainId[chainId];
+  if (!network) {
+    return null;
+  }
+  return `https://${network}.g.alchemy.com/v2/${apiKey}`;
+}
+
+export function isAlchemySupported(chainId: number): boolean {
+  return chainId in alchemyNetworkByChainId;
+}

src/core/chains.ts

@@ -1,4 +1,5 @@
 import { type Chain } from 'viem';
+import { getAlchemyRpcUrl } from './alchemy.js';
 import {
   // Mainnets
   mainnet,
@@ -342,7 +343,14 @@ export function getRpcUrl(chainIdentifier: number | string = DEFAULT_CHAIN_ID):
   const chainId = typeof chainIdentifier === 'string' 
     ? resolveChainId(chainIdentifier) 
     : chainIdentifier;
-
+
+  if (process.env.ALCHEMY_API_KEY) {
+    const alchemyUrl = getAlchemyRpcUrl(chainId, process.env.ALCHEMY_API_KEY);
+    if (alchemyUrl) {
+      return alchemyUrl;
+    }
+  }
+
   return rpcUrlMap[chainId] || DEFAULT_RPC_URL;
 }