diff --git a/api/default_networks.go b/api/default_networks.go
index a4d636b69..c4947dfaf 100644
--- a/api/default_networks.go
+++ b/api/default_networks.go
@@ -117,8 +117,8 @@ var optimismGoerli = params.Network{
 var optimismSepolia = params.Network{
 	ChainID:                optimismSepoliaChainID,
 	ChainName:              "Optimism",
-	RPCURL:                 "https://optimism-sepolia.infura.io/v3/",
-	FallbackURL:            "",
+	RPCURL:                 "https://optimism-sepolia-archival.rpc.grove.city/v1/",
+	FallbackURL:            "https://optimism-sepolia.infura.io/v3/",
 	BlockExplorerURL:       "https://sepolia-optimism.etherscan.io/",
 	IconURL:                "network/Network=Optimism",
 	ChainColor:             "#E90101",
@@ -171,8 +171,8 @@ var arbitrumGoerli = params.Network{
 var arbitrumSepolia = params.Network{
 	ChainID:                arbitrumSepoliaChainID,
 	ChainName:              "Arbitrum",
-	RPCURL:                 "https://arbitrum-sepolia.infura.io/v3/",
-	FallbackURL:            "",
+	RPCURL:                 "https://arbitrum-sepolia-archival.rpc.grove.city/v1/",
+	FallbackURL:            "https://arbitrum-sepolia.infura.io/v3/",
 	BlockExplorerURL:       "https://sepolia-explorer.arbitrum.io/",
 	IconURL:                "network/Network=Arbitrum",
 	ChainColor:             "#51D0F0",
diff --git a/api/default_networks_test.go b/api/default_networks_test.go
index f61570587..e57645b2c 100644
--- a/api/default_networks_test.go
+++ b/api/default_networks_test.go
@@ -48,8 +48,8 @@ func TestBuildDefaultNetworks(t *testing.T) {
 
 	require.Equal(t, optimismSepoliaChainID, actualNetworks[5].ChainID)
 
-	require.True(t, strings.Contains(actualNetworks[5].RPCURL, infuraToken))
-	require.Equal(t, "", actualNetworks[5].FallbackURL)
+	require.True(t, strings.Contains(actualNetworks[5].RPCURL, poktToken))
+	require.True(t, strings.Contains(actualNetworks[5].FallbackURL, infuraToken))
 
 	require.Equal(t, arbitrumChainID, actualNetworks[6].ChainID)
 
@@ -63,8 +63,8 @@ func TestBuildDefaultNetworks(t *testing.T) {
 
 	require.Equal(t, arbitrumSepoliaChainID, actualNetworks[8].ChainID)
 
-	require.True(t, strings.Contains(actualNetworks[8].RPCURL, infuraToken))
-	require.Equal(t, "", actualNetworks[8].FallbackURL)
+	require.True(t, strings.Contains(actualNetworks[8].RPCURL, poktToken))
+	require.True(t, strings.Contains(actualNetworks[8].FallbackURL, infuraToken))
 }
 
 func TestBuildDefaultNetworksGanache(t *testing.T) {