diff --git a/common/src/combat.rs b/common/src/combat.rs
index 371ec66297..2b77be0e8c 100644
--- a/common/src/combat.rs
+++ b/common/src/combat.rs
@@ -982,6 +982,7 @@ const SLASHING_ENERGY_FRACTION: f32 = 0.5;
 const CRUSHING_POISE_FRACTION: f32 = 1.0;
 
 #[derive(Copy, Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct Damage {
     pub source: DamageSource,
     pub kind: DamageKind,
diff --git a/common/src/comp/aura.rs b/common/src/comp/aura.rs
index 212c73365d..5f462a97c3 100644
--- a/common/src/comp/aura.rs
+++ b/common/src/comp/aura.rs
@@ -141,6 +141,7 @@ impl Auras {
 }
 
 #[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(deny_unknown_fields)]
 pub struct AuraBuffConstructor {
     pub kind: BuffKind,
     pub strength: f32,
diff --git a/common/src/comp/health.rs b/common/src/comp/health.rs
index 2476169571..3837166bb2 100644
--- a/common/src/comp/health.rs
+++ b/common/src/comp/health.rs
@@ -8,6 +8,7 @@ use std::{convert::TryFrom, ops::Mul};
 
 /// Specifies what and how much changed current health
 #[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(deny_unknown_fields)]
 pub struct HealthChange {
     /// The amount of the health change, negative is damage, positive is healing
     pub amount: f32,
diff --git a/common/src/comp/inventory/item/armor.rs b/common/src/comp/inventory/item/armor.rs
index f85213d88f..7778c26afa 100644
--- a/common/src/comp/inventory/item/armor.rs
+++ b/common/src/comp/inventory/item/armor.rs
@@ -99,6 +99,7 @@ impl Friction {
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Serialize, Deserialize, Default)]
+#[serde(deny_unknown_fields)]
 pub struct Stats {
     /// Protection is non-linearly transformed (following summation) to a damage
     /// reduction using (prot / (60 + prot))
@@ -232,6 +233,7 @@ impl PartialOrd for Protection {
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct Armor {
     pub kind: ArmorKind,
     pub stats: StatsSource,
diff --git a/common/src/comp/inventory/item/mod.rs b/common/src/comp/inventory/item/mod.rs
index c59db7dc19..f6e84da511 100644
--- a/common/src/comp/inventory/item/mod.rs
+++ b/common/src/comp/inventory/item/mod.rs
@@ -57,6 +57,7 @@ pub enum Utility {
 }
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct Lantern {
     color: Rgb<u32>,
     strength_thousandths: u32,
@@ -335,6 +336,7 @@ impl Effects {
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub enum ItemKind {
     /// Something wieldable
     Tool(Tool),
@@ -875,7 +877,7 @@ impl assets::Compound for ItemDef {
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
-#[serde(rename = "ItemDef")]
+#[serde(rename = "ItemDef", deny_unknown_fields)]
 struct RawItemDef {
     legacy_name: String,
     legacy_description: String,
diff --git a/common/src/comp/inventory/item/modular.rs b/common/src/comp/inventory/item/modular.rs
index 29be4079f3..f7ab0fad51 100644
--- a/common/src/comp/inventory/item/modular.rs
+++ b/common/src/comp/inventory/item/modular.rs
@@ -236,6 +236,7 @@ impl ModularBase {
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub enum ModularComponent {
     ToolPrimaryComponent {
         toolkind: ToolKind,
diff --git a/common/src/effect.rs b/common/src/effect.rs
index c55b338b71..cc61ec6e85 100644
--- a/common/src/effect.rs
+++ b/common/src/effect.rs
@@ -12,6 +12,7 @@ pub enum Effect {
 
 /// A buff that may be applied to an entity
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct BuffEffect {
     pub kind: comp::BuffKind,
     pub data: comp::BuffData,