diff --git a/src/main.rs b/src/main.rs
index 7b161c4..fbb8d9a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -679,7 +679,7 @@ mod tests {
         let mut hooks = BTreeMap::new();
 
         hooks.insert(
-            "test_hook".to_string(),
+            "test_hook0".to_string(),
             Hook {
                 command:
                     "/usr/bin/echo {{ /repository/full_name }} --foo {{ /pull_request/base/ref }}"
@@ -695,7 +695,7 @@ mod tests {
         );
 
         hooks.insert(
-            "test_hook".to_string(),
+            "test_hook2".to_string(),
             Hook {
                 command: "/usr/bin/echo {{ /repository/full_name }} {{ /pull_request/base/ref }}"
                     .to_string(),
@@ -709,6 +709,21 @@ mod tests {
             },
         );
 
+        hooks.insert(
+            "test_hook3".to_string(),
+            Hook {
+                command: "/usr/bin/echo {{ /repository/full_name }} {{ /pull_request/base/ref }}"
+                    .to_string(),
+                signature: "X-Gitea-Signature".to_string(),
+                ip_filter: None,
+                secrets: vec!["valid".to_string()],
+                filter: FilterType::Not(Box::new(FilterType::JsonFilter(JsonFilter {
+                    pointer: "/foobar".to_string(),
+                    regex: "bar".to_string(),
+                }))),
+            },
+        );
+
         let config = Config {
             metrics: None,
             hooks: hooks,
diff --git a/src/webhooks.rs b/src/webhooks.rs
index efd9fb6..0c4ee15 100644
--- a/src/webhooks.rs
+++ b/src/webhooks.rs
@@ -93,6 +93,7 @@ impl JsonFilter {
 #[derive(Debug, Deserialize, Serialize)]
 #[serde(deny_unknown_fields, rename_all = "lowercase")]
 pub enum FilterType {
+    Not(Box<FilterType>),
     And(Vec<FilterType>),
     Or(Vec<FilterType>),
     #[serde(rename = "json")]
@@ -102,6 +103,7 @@ pub enum FilterType {
 impl FilterType {
     pub fn evaluate(&self, data: &serde_json::Value) -> Result<bool, WebhookeyError> {
         match self {
+            FilterType::Not(filter) => Ok(!filter.evaluate(data)?),
             FilterType::And(filters) => {
                 let (mut results, mut errors) = (Vec::new(), Vec::new());