diff --git a/index.html b/index.html
index b4ba309..7ae713e 100644
--- a/index.html
+++ b/index.html
@@ -87,6 +87,10 @@
                 floGlobals.myBscID = floGlobals.myEthID;
                 // MATIC (Polygon) uses same address format as Ethereum
                 floGlobals.myMaticID = floGlobals.myEthID;
+                // Arbitrum uses same address format as Ethereum
+                floGlobals.myArbID = floGlobals.myEthID;
+                // Optimism uses same address format as Ethereum
+                floGlobals.myOpID = floGlobals.myEthID;
                 // HBAR (Hedera) uses same address format as Ethereum
                 floGlobals.myHbarID = floGlobals.myEthID;
 
@@ -264,6 +268,8 @@
             <button class="button w-100" onclick="resolveBlockchainSelection('DOT')">Polkadot (DOT)</button>
             <button class="button w-100" onclick="resolveBlockchainSelection('SOL')">Solana (SOL)</button>
             <button class="button w-100" onclick="resolveBlockchainSelection('HBAR')">Hedera (HBAR)</button>
+            <button class="button w-100" onclick="resolveBlockchainSelection('ARB')">Arbitrum (ARB)</button>
+            <button class="button w-100" onclick="resolveBlockchainSelection('OP')">Optimism (OP)</button>
         </div>
         <div class="flex align-center gap-0-5 margin-top-1 margin-left-auto">
             <button class="button cancel-button" onclick="resolveBlockchainSelection(null)">Cancel</button>
@@ -2062,15 +2068,17 @@
                     removeNotificationBadge('#chat_page_button')
                     if (floGlobals.idInterval)
                         clearInterval(floGlobals.idInterval)
-                    // Cycle through all blockchain addresses: FLO -> BTC -> ETH -> AVAX -> BSC -> MATIC -> HBAR -> XRP -> SUI -> TON -> TRON -> DOGE -> LTC -> BCH -> DOT -> ALGO -> XLM -> SOL
+                    let activeChain = localStorage.getItem(`${floGlobals.application}#activeChain`) || 'FLO';
                     let currentIdIndex = 0
-                    const idList = [
+                    const allIds = [
                         { id: floGlobals.myFloID, label: 'FLO' },
                         { id: floGlobals.myBtcID, label: 'BTC' },
                         { id: floGlobals.myEthID, label: 'ETH' },
                         { id: floGlobals.myAvaxID, label: 'AVAX' },
                         { id: floGlobals.myBscID, label: 'BSC' },
                         { id: floGlobals.myMaticID, label: 'MATIC' },
+                        { id: floGlobals.myArbID, label: 'ARB' },
+                        { id: floGlobals.myOpID, label: 'OP' },
                         { id: floGlobals.myHbarID, label: 'HBAR' },
                         { id: floGlobals.myXrpID, label: 'XRP' },
                         { id: floGlobals.mySuiID, label: 'SUI' },
@@ -2084,7 +2092,16 @@
                         { id: floGlobals.myXlmID, label: 'XLM' },
                         { id: floGlobals.mySolID, label: 'SOL' },
                         { id: floGlobals.myAdaID, label: 'ADA' }
-                    ].filter(item => item.id)
+                    ];
+
+                    const idList = allIds.filter(item => {
+                        if (!item.id) return false;
+                        if (item.label === 'FLO') return true; // Always include FLO
+                        if (item.label === activeChain) return true; // Include active chain
+                        // For EVM compatible chains which share the ETH ID:
+                        if (['ETH', 'AVAX', 'BSC', 'MATIC', 'ARB', 'OP', 'HBAR'].includes(activeChain) && item.label === activeChain) return true;
+                        return false;
+                    });
                     floGlobals.idInterval = setInterval(() => {
                         currentIdIndex = (currentIdIndex + 1) % idList.length
                         document.querySelectorAll('.user-profile-id').forEach(el => el.textContent = idList[currentIdIndex].id)
@@ -3284,6 +3301,14 @@
                             <b>My MATIC (Polygon) address</b>
                             <sm-copy class="user-matic-id" value=${floGlobals.myMaticID}></sm-copy>
                         </div>
+                        <div class="grid gap-0-5">
+                            <b>My ARB (Arbitrum) address</b>
+                            <sm-copy class="user-arb-id" value=${floGlobals.myArbID}></sm-copy>
+                        </div>
+                        <div class="grid gap-0-5">
+                            <b>My OP (Optimism) address</b>
+                            <sm-copy class="user-op-id" value=${floGlobals.myOpID}></sm-copy>
+                        </div>
                         <div class="grid gap-0-5">
                             <b>My HBAR (Hedera) address</b>
                             <sm-copy class="user-hbar-id" value=${floGlobals.myHbarID}></sm-copy>
diff --git a/scripts/blockchainAddresses.js b/scripts/blockchainAddresses.js
index eb48a4f..d708a91 100644
--- a/scripts/blockchainAddresses.js
+++ b/scripts/blockchainAddresses.js
@@ -9,6 +9,8 @@
  * - AVAX (Avalanche C-Chain) - same as ETH (EVM-compatible)
  * - BSC (Binance Smart Chain) - same as ETH (EVM-compatible)
  * - MATIC (Polygon) - same as ETH (EVM-compatible)
+ * - ARB (Arbitrum) - same as ETH (EVM-compatible)
+ * - OP (Optimism) - same as ETH (EVM-compatible)
  * - HBAR (Hedera) - same as ETH (EVM-compatible)
  * - XRP (Ripple) - via xrpl library
  * - SUI - via nacl + BLAKE2b
@@ -423,6 +425,8 @@ async function deriveAllBlockchainAddresses(wif) {
     bsc: null,
     matic: null,
     hbar: null,
+    arb: null,
+    op: null,
     xrp: null,
     sui: null,
     ton: null,
@@ -438,13 +442,15 @@ async function deriveAllBlockchainAddresses(wif) {
   };
 
   try {
-    // BSC, MATIC, and HBAR use same address as ETH (requires public key, not WIF)
+    // BSC, MATIC, HBAR, ARB, and OP use same address as ETH (requires public key, not WIF)
     // These will be set from floGlobals.myEthID in the main code
     addresses.bsc = null; // Set in main code as same as ETH
     addresses.matic = null; // Set in main code as same as ETH
     addresses.hbar = null; // Set in main code as same as ETH
+    addresses.arb = null; // Set in main code as same as ETH
+    addresses.op = null; // Set in main code as same as ETH
   } catch (e) {
-    console.warn("BSC/MATIC/HBAR derivation failed:", e);
+    console.warn("BSC/MATIC/HBAR/ARB/OP derivation failed:", e);
   }
   try {
     addresses.xrp = convertWIFtoXrpAddress(wif);
diff --git a/scripts/messenger.js b/scripts/messenger.js
index 1441241..262fb48 100644
--- a/scripts/messenger.js
+++ b/scripts/messenger.js
@@ -86,7 +86,7 @@
         if ((address.length === 33 || address.length === 34) && /^[1-9A-HJ-NP-Za-km-z]+$/.test(address)) {
             return floCrypto.validateAddr(address) || true;
         }
-        // Ethereum/EVM addresses (0x prefix, 40 hex chars) - ETH, AVAX, BSC, MATIC
+        // Ethereum/EVM addresses (0x prefix, 40 hex chars) - ETH, AVAX, BSC, MATIC, ARB, OP
         if (/^0x[a-fA-F0-9]{40}$/.test(address)) return true;
         // SUI addresses (0x prefix, 64 hex chars)
         if (/^0x[a-fA-F0-9]{64}$/.test(address)) return true;
@@ -152,6 +152,8 @@
                         case 'AVAX':
                         case 'BSC':
                         case 'MATIC':
+                        case 'ARB':
+                        case 'OP':
                         case 'HBAR':
                             proxyID = floEthereum.ethAddressFromCompressedPublicKey(user.public); break;
                         case 'BTC': proxyID = floGlobals.myBtcID; break;
@@ -632,6 +634,8 @@
                     case 'AVAX':
                     case 'BSC':
                     case 'MATIC':
+                    case 'ARB':
+                    case 'OP':
                     case 'HBAR':
                         addIfValid(floEthereum.ethAddressFromCompressedPublicKey(user.public));
                         break;
@@ -655,7 +659,8 @@
                 const allDerived = [
                     floEthereum.ethAddressFromCompressedPublicKey(user.public),
                     floGlobals.myBtcID, floGlobals.myAvaxID, floGlobals.myBscID,
-                    floGlobals.myMaticID, floGlobals.myHbarID, floGlobals.myXrpID,
+                    floGlobals.myMaticID, floGlobals.myArbID, floGlobals.myOpID,
+                    floGlobals.myHbarID, floGlobals.myXrpID,
                     floGlobals.mySuiID, floGlobals.myTonID, floGlobals.myTronID,
                     floGlobals.myDogeID, floGlobals.myLtcID, floGlobals.myBchID,
                     floGlobals.myDotID, floGlobals.myAlgoID, floGlobals.myXlmID,