diff --git a/cmd/metal-api/internal/service/v1/machine.go b/cmd/metal-api/internal/service/v1/machine.go
index 54cfd9c8b..e3abd87aa 100644
--- a/cmd/metal-api/internal/service/v1/machine.go
+++ b/cmd/metal-api/internal/service/v1/machine.go
@@ -43,7 +43,7 @@ type MachineAllocation struct {
 	Role             string                    `json:"role" enum:"machine|firewall" description:"the role of the machine"`
 	VPN              *MachineVPN               `json:"vpn" description:"vpn connection info for machine" optional:"true"`
 	AllocationUUID   string                    `json:"allocationuuid" description:"a unique identifier for this machine allocation, can be used to distinguish between machine allocations over time."`
-	FirewallRules    *FirewallRules            `json:"firewall_rules" description:"a set of firewall rules to apply"`
+	FirewallRules    *FirewallRules            `json:"firewall_rules,omitempty" description:"a set of firewall rules to apply" optional:"true"`
 }
 
 type FirewallRules struct {
diff --git a/spec/metal-api.json b/spec/metal-api.json
index ab1dab9ba..c5a1cb49f 100644
--- a/spec/metal-api.json
+++ b/spec/metal-api.json
@@ -2176,7 +2176,6 @@
         "allocationuuid",
         "created",
         "creator",
-        "firewall_rules",
         "hostname",
         "name",
         "networks",