diff --git a/config/config.go b/config/config.go
index b5bd6e65..78b41d1c 100644
--- a/config/config.go
+++ b/config/config.go
@@ -153,7 +153,7 @@ func MergeChainConfigs(chainConfigs []map[string]interface{}, solverConfig solve
 		}
 
 		cc := map[string]interface{}{
-			"id":       id,
+			"id":       float64(id),
 			"type":     "evm",
 			"name":     fmt.Sprintf("chain-%d", id),
 			"endpoint": c.Transport.HTTP[0],
@@ -166,8 +166,8 @@ func MergeChainConfigs(chainConfigs []map[string]interface{}, solverConfig solve
 
 func chainExists(chainConfigs []map[string]interface{}, chainID uint64) bool {
 	for _, cc := range chainConfigs {
-		ccID := cc["id"].(uint64)
-		if ccID == chainID {
+		ccID := cc["id"].(float64)
+		if uint64(ccID) == chainID {
 			return true
 		}
 	}
diff --git a/config/config_test.go b/config/config_test.go
index 03ee181c..bff606dc 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -602,7 +602,7 @@ func (s *MergeChainConfigsTestSuite) Test_MergeChainConfigs_AddsChainFromSolverC
 
 	s.Len(merged, 1)
 	s.Equal(map[string]interface{}{
-		"id":       uint64(10),
+		"id":       float64(10),
 		"type":     "evm",
 		"name":     "chain-10",
 		"endpoint": "https://chain10.example",
@@ -620,7 +620,7 @@ func (s *MergeChainConfigsTestSuite) Test_MergeChainConfigs_ManuallyConfiguredCh
 
 	manual := []map[string]interface{}{
 		{
-			"id":       uint64(10),
+			"id":       float64(10),
 			"endpoint": "https://custom.example",
 			"admin":    "adminAddress",
 		},
@@ -634,7 +634,7 @@ func (s *MergeChainConfigsTestSuite) Test_MergeChainConfigs_ManuallyConfiguredCh
 func (s *MergeChainConfigsTestSuite) Test_MergeChainConfigs_KeepsManualOnlyChains() {
 	manual := []map[string]interface{}{
 		{
-			"id":       uint64(99),
+			"id":       float64(99),
 			"type":     "evm",
 			"endpoint": "https://manual-only.example",
 			"name":     "manual99",