diff --git a/src/constants.ts b/src/constants.ts
index 49de03f..7e4b83b 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -1,5 +1,5 @@
 import { ChainID, ChainType, Unit } from '@harmony-js/utils'
-import { ContractAddresses, HarmonyRpcConfig, HarmonyShards, ITransactionOptions } from './interfaces'
+import { ChainId, ContractAddresses, HarmonyRpcConfig, HarmonyShards, ITransactionOptions } from './interfaces'
 
 export const AddressZero = '0x0000000000000000000000000000000000000000'
 export const DEFAULT_GAS_PRICE = '1000000000'
@@ -8,6 +8,10 @@ export const HARMONY_RPC_SHARD_0_URL = 'https://api.harmony.one'
 export const HARMONY_RPC_SHARD_1_URL = 'https://s1.api.harmony.one'
 export const HARMONY_RPC_SHARD_2_URL = 'https://s2.api.harmony.one'
 export const HARMONY_RPC_SHARD_3_URL = 'https://s3.api.harmony.one'
+export const HARMONY_RPC_SHARD_0_TESTNET_URL = 'https://api.s0.b.hmny.io'
+export const HARMONY_RPC_SHARD_1_TESTNET_URL = 'https://api.s1.b.hmny.io'
+export const HARMONY_RPC_SHARD_2_TESTNET_URL = 'https://api.s2.b.hmny.io'
+export const HARMONY_RPC_SHARD_3_TESTNET_URL = 'https://api.s3.b.hmny.io'
 export const HARMONY_RPC_SHARD_0_DEVNET_URL = 'https://api.s0.ps.hmny.io'
 export const HARMONY_RPC_WS = 'wss://ws.s0.t.hmny.io'
 export const HARMONY_RPC_DEVNET_WS = 'wss://ws.s0.ps.hmny.io'
@@ -45,6 +49,18 @@ export const HARMONY_SHARDS = {
   [HarmonyShards.SHARD_0_DEVNET]: HARMONY_RPC_SHARD_0_DEVNET,
 }
 
+export const CHAINS_ID: ChainId = {
+  1666600000: HARMONY_RPC_SHARD_0_URL,
+  1666600001: HARMONY_RPC_SHARD_1_URL,
+  1666600002: HARMONY_RPC_SHARD_2_URL,
+  1666600003: HARMONY_RPC_SHARD_3_URL,
+  1666700000: HARMONY_RPC_SHARD_0_TESTNET_URL,
+  1666700001: HARMONY_RPC_SHARD_1_TESTNET_URL,
+  1666700002: HARMONY_RPC_SHARD_2_TESTNET_URL,
+  1666700003: HARMONY_RPC_SHARD_3_TESTNET_URL,
+  1666900000: HARMONY_RPC_SHARD_0_DEVNET_URL,
+}
+
 export enum NetworkInfo {
   MAINNET,
   DEVNET,
diff --git a/src/interfaces.ts b/src/interfaces.ts
index 19579c1..1c44e1b 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -80,3 +80,7 @@ export interface BridgeResponse {
   addr: string
   receiptId: string
 }
+
+export interface ChainId {
+  [key: number]: string
+}
diff --git a/src/wallets/key.ts b/src/wallets/key.ts
index ac82112..6df2c40 100644
--- a/src/wallets/key.ts
+++ b/src/wallets/key.ts
@@ -1,7 +1,7 @@
 import { Wallet } from '@harmony-js/account'
 import { Messenger, HttpProvider, WSProvider } from '@harmony-js/network'
 import { ChainID, ChainType, isWs } from '@harmony-js/utils'
-import { HARMONY_SHARDS } from '../constants'
+import { HARMONY_SHARDS, CHAINS_ID } from '../constants'
 import { HarmonyRpcConfig, HarmonyShards, RpcProviderType } from '../interfaces'
 
 /**
@@ -21,6 +21,14 @@ export class Key extends Wallet {
       provider = url
     } else if (typeof url === 'string') {
       provider = isWs(url) ? new WSProvider(url) : new HttpProvider(url)
+    } else if (url['isMetaMask']) {
+      const _chain = Number(url['networkVersion'])
+      const rpc_url = CHAINS_ID[_chain]
+
+      if (!rpc_url) throw new Error('Invalid metamask harmony chain.')
+
+      provider = new HttpProvider(rpc_url)
+      chain = _chain
     } else {
       throw new Error('Invalid url param.')
     }