From b6a3165a69d04c16ca8a6d02dfe2d9cab9223798 Mon Sep 17 00:00:00 2001
From: Wonhee Lee <2wheeh@gmail.com>
Date: Mon, 15 Jun 2026 11:48:44 +0900
Subject: [PATCH 1/2] feat(chains): add MarooTestnet (450815)

---
 .changeset/plain-jeans-itch.md         |  5 +++++
 src/chains/definitions/marooTestnet.ts | 26 ++++++++++++++++++++++++++
 src/chains/index.ts                    |  1 +
 3 files changed, 32 insertions(+)
 create mode 100644 .changeset/plain-jeans-itch.md
 create mode 100644 src/chains/definitions/marooTestnet.ts

diff --git a/.changeset/plain-jeans-itch.md b/.changeset/plain-jeans-itch.md
new file mode 100644
index 0000000000..d0f61ca475
--- /dev/null
+++ b/.changeset/plain-jeans-itch.md
@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+Added MarooTestnet chain.
diff --git a/src/chains/definitions/marooTestnet.ts b/src/chains/definitions/marooTestnet.ts
new file mode 100644
index 0000000000..26b9f39ebe
--- /dev/null
+++ b/src/chains/definitions/marooTestnet.ts
@@ -0,0 +1,26 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const marooTestnet = /*#__PURE__*/ defineChain({
+  id: 450815,
+  name: 'Maroo Testnet',
+  nativeCurrency: { name: 'Testnet OKRW', symbol: 'tOKRW', decimals: 18 },
+  rpcUrls: {
+    default: {
+      http: ['https://rpc-testnet.maroo.io'],
+    },
+  },
+  blockExplorers: {
+    default: {
+      name: 'Blockscout',
+      url: 'https://explorer-testnet.maroo.io',
+      apiUrl: 'https://explorer-testnet.maroo.io/blockscout/api',
+    },
+  },
+  contracts: {
+    multicall3: {
+      address: '0xcA11bde05977b3631167028862bE2a173976CA11',
+      blockCreated: 0,
+    },
+  },
+  testnet: true,
+})
diff --git a/src/chains/index.ts b/src/chains/index.ts
index f4326f505e..7d2f7d03bc 100644
--- a/src/chains/index.ts
+++ b/src/chains/index.ts
@@ -390,6 +390,7 @@ export { mantleTestnet } from './definitions/mantleTestnet.js'
 export { mantraDuKongEVMTestnet } from './definitions/mantraDuKongEVMTestnet.js'
 export { mantraEVM } from './definitions/mantraEVM.js'
 export { mapProtocol } from './definitions/mapProtocol.js'
+export { marooTestnet } from './definitions/marooTestnet.js'
 export { matchain } from './definitions/matchain.js'
 export { matchainTestnet } from './definitions/matchainTestnet.js'
 export { mchVerse } from './definitions/mchVerse.js'

From fd730d7b5714743f76fbca417e554cb4a1e7a3cc Mon Sep 17 00:00:00 2001
From: Wonhee Lee <2wheeh@gmail.com>
Date: Thu, 18 Jun 2026 23:12:27 +0900
Subject: [PATCH 2/2] up

---
 src/chains/definitions/marooTestnet.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/chains/definitions/marooTestnet.ts b/src/chains/definitions/marooTestnet.ts
index 26b9f39ebe..cd60c0ccd1 100644
--- a/src/chains/definitions/marooTestnet.ts
+++ b/src/chains/definitions/marooTestnet.ts
@@ -1,12 +1,13 @@
 import { defineChain } from '../../utils/chain/defineChain.js'
 
 export const marooTestnet = /*#__PURE__*/ defineChain({
-  id: 450815,
+  id: 450_815,
   name: 'Maroo Testnet',
   nativeCurrency: { name: 'Testnet OKRW', symbol: 'tOKRW', decimals: 18 },
   rpcUrls: {
     default: {
       http: ['https://rpc-testnet.maroo.io'],
+      webSocket: ['wss://ws-testnet.maroo.io'],
     },
   },
   blockExplorers: {