diff --git a/license/plans.go b/license/plans.go
index 5d969a2..c4d2197 100644
--- a/license/plans.go
+++ b/license/plans.go
@@ -22,7 +22,9 @@ var plans = map[string]Plan{
 		Name:       "Free",
 		Deployment: DeploymentCloud, // cloud only, by construction
 		Limits:     Limits{MaxServers: 3, MaxSecretGroups: 1, MaxChannels: 1},
-		Features:   nil,
+		// Empty rather than nil: nil marshals as JSON null, and this table is
+		// the seed every plan and licence is cut from.
+		Features: []string{},
 	},
 	TierProfessional: {
 		Tier:       TierProfessional,