diff --git a/db/patch-add-invert-keyword.sql b/db/patch-add-invert-keyword.sql
new file mode 100644
index 000000000..8ca199eed
--- /dev/null
+++ b/db/patch-add-invert-keyword.sql
@@ -0,0 +1,7 @@
+-- You should not modify if this have pushed to Github, unless it does serious wrong with the db.
+BEGIN TRANSACTION;
+
+ALTER TABLE monitor
+    ADD invert_keyword BOOLEAN default 0 not null;
+
+COMMIT;
diff --git a/server/database.js b/server/database.js
index 8576bdedc..6201a08b4 100644
--- a/server/database.js
+++ b/server/database.js
@@ -70,6 +70,7 @@ class Database {
         "patch-api-key-table.sql": true,
         "patch-monitor-tls.sql": true,
         "patch-maintenance-cron.sql": true,
+        "patch-add-invert-keyword.sql": true,
     };
 
     /**
diff --git a/server/model/monitor.js b/server/model/monitor.js
index b4a0ba2a3..f6732b69d 100644
--- a/server/model/monitor.js
+++ b/server/model/monitor.js
@@ -84,6 +84,7 @@ class Monitor extends BeanModel {
             retryInterval: this.retryInterval,
             resendInterval: this.resendInterval,
             keyword: this.keyword,
+            invertKeyword: this.isInvertKeyword(),
             expiryNotification: this.isEnabledExpiryNotification(),
             ignoreTls: this.getIgnoreTls(),
             upsideDown: this.isUpsideDown(),
@@ -183,6 +184,14 @@ class Monitor extends BeanModel {
         return Boolean(this.upsideDown);
     }
 
+    /**
+     * Parse to boolean
+     * @returns {boolean}
+     */
+    isInvertKeyword() {
+        return Boolean(this.invertKeyword);
+    }
+
     /**
      * Parse to boolean
      * @returns {boolean}
@@ -394,15 +403,17 @@ class Monitor extends BeanModel {
                             data = JSON.stringify(data);
                         }
 
-                        if (data.includes(this.keyword)) {
-                            bean.msg += ", keyword is found";
+                        let keyword_found = data.includes(this.keyword);
+                        if (keyword_found == !this.isInvertKeyword()) {
+                            bean.msg += ", keyword " + (keyword_found ? "is" : "not") + " found";
                             bean.status = UP;
                         } else {
                             data = data.replace(/<[^>]*>?|[\n\r]|\s+/gm, " ");
                             if (data.length > 50) {
                                 data = data.substring(0, 47) + "...";
                             }
-                            throw new Error(bean.msg + ", but keyword is not in [" + data + "]");
+                            throw new Error(bean.msg + ", but keyword is " +
+                                (keyword_found ? "present" : "not") + " in [" + data + "]");
                         }
 
                     }
@@ -603,7 +614,6 @@ class Monitor extends BeanModel {
                         grpcEnableTls: this.grpcEnableTls,
                         grpcMethod: this.grpcMethod,
                         grpcBody: this.grpcBody,
-                        keyword: this.keyword
                     };
                     const response = await grpcQuery(options);
                     bean.ping = dayjs().valueOf() - startTime;
@@ -616,13 +626,14 @@ class Monitor extends BeanModel {
                         bean.status = DOWN;
                         bean.msg = `Error in send gRPC ${response.code} ${response.errorMessage}`;
                     } else {
-                        if (response.data.toString().includes(this.keyword)) {
+                        let keyword_found = response.data.toString().includes(this.keyword)
+                        if (keyword_found == !this.isInvertKeyword()) {
                             bean.status = UP;
-                            bean.msg = `${responseData}, keyword [${this.keyword}] is found`;
+                            bean.msg = `${responseData}, keyword [${this.keyword}] ${keyword_found ? "is" : "not"} found`;
                         } else {
-                            log.debug("monitor:", `GRPC response [${response.data}] + ", but keyword [${this.keyword}] is not in [" + ${response.data} + "]"`);
+                            log.debug("monitor:", `GRPC response [${response.data}] + ", but keyword [${this.keyword}] is ${keyword_found ? "present" : "not"} in [" + ${response.data} + "]"`);
                             bean.status = DOWN;
-                            bean.msg = `, but keyword [${this.keyword}] is not in [" + ${responseData} + "]`;
+                            bean.msg = `, but keyword [${this.keyword}] is ${keyword_found ? "present" : "not"} in [" + ${responseData} + "]`;
                         }
                     }
                 } else if (this.type === "postgres") {
diff --git a/server/server.js b/server/server.js
index ac2851ab4..cd2d9966d 100644
--- a/server/server.js
+++ b/server/server.js
@@ -699,6 +699,7 @@ let needSetup = false;
                 bean.maxretries = monitor.maxretries;
                 bean.port = parseInt(monitor.port);
                 bean.keyword = monitor.keyword;
+                bean.invertKeyword = monitor.invertKeyword;
                 bean.ignoreTls = monitor.ignoreTls;
                 bean.expiryNotification = monitor.expiryNotification;
                 bean.upsideDown = monitor.upsideDown;
@@ -1345,6 +1346,7 @@ let needSetup = false;
                                 maxretries: monitorListData[i].maxretries,
                                 port: monitorListData[i].port,
                                 keyword: monitorListData[i].keyword,
+                                invertKeyword: monitorListData[i].invertKeyword,
                                 ignoreTls: monitorListData[i].ignoreTls,
                                 upsideDown: monitorListData[i].upsideDown,
                                 maxredirects: monitorListData[i].maxredirects,
diff --git a/src/lang/en.json b/src/lang/en.json
index 4a2fe8813..a0cdaf058 100644
--- a/src/lang/en.json
+++ b/src/lang/en.json
@@ -48,6 +48,7 @@
     "Ping": "Ping",
     "Monitor Type": "Monitor Type",
     "Keyword": "Keyword",
+    "Invert Keyword": "Invert Keyword",
     "Friendly Name": "Friendly Name",
     "URL": "URL",
     "Hostname": "Hostname",
@@ -511,6 +512,7 @@
     "passwordNotMatchMsg": "The repeat password does not match.",
     "notificationDescription": "Notifications must be assigned to a monitor to function.",
     "keywordDescription": "Search keyword in plain HTML or JSON response. The search is case-sensitive.",
+    "invertKeywordDescription": "Look for the keyword to be absent rather than present.",
     "backupDescription": "You can backup all monitors and notifications into a JSON file.",
     "backupDescription2": "Note: history and event data is not included.",
     "backupDescription3": "Sensitive data such as notification tokens are included in the export file; please store export securely.",
diff --git a/src/pages/Details.vue b/src/pages/Details.vue
index ba034136c..ff3af096a 100644
--- a/src/pages/Details.vue
+++ b/src/pages/Details.vue
@@ -12,7 +12,9 @@
                 <span v-if="monitor.type === 'ping'">Ping: {{ monitor.hostname }}</span>
                 <span v-if="monitor.type === 'keyword'">
                     <br>
-                    <span>{{ $t("Keyword") }}:</span> <span class="keyword">{{ monitor.keyword }}</span>
+                    <span>{{ $t("Keyword") }}: </span>
+                    <span class="keyword">{{ monitor.keyword }}</span>
+                    <span v-if="monitor.invertKeyword" alt="Inverted keyword" class="keyword-inverted"> ↧</span>
                 </span>
                 <span v-if="monitor.type === 'dns'">[{{ monitor.dns_resolve_type }}] {{ monitor.hostname }}
                     <br>
@@ -490,6 +492,10 @@ table {
         color: $dark-font-color;
     }
 
+    .keyword-inverted {
+        color: $dark-font-color;
+    }
+
     .dropdown-clear-data {
         ul {
             background-color: $dark-bg;
diff --git a/src/pages/EditMonitor.vue b/src/pages/EditMonitor.vue
index 997faf955..04270f694 100644
--- a/src/pages/EditMonitor.vue
+++ b/src/pages/EditMonitor.vue
@@ -120,6 +120,17 @@
                                 </div>
                             </div>
 
+                            <!-- Invert keyword -->
+                            <div v-if="monitor.type === 'keyword' || monitor.type === 'grpc-keyword'" class="my-3 form-check">
+                                <input id="invert-keyword" v-model="monitor.invertKeyword" class="form-check-input" type="checkbox">
+                                <label class="form-check-label" for="invert-keyword">
+                                    {{ $t("Invert Keyword") }}
+                                </label>
+                                <div class="form-text">
+                                    {{ $t("invertKeywordDescription") }}
+                                </div>
+                            </div>
+
                             <!-- Game -->
                             <!-- GameDig only -->
                             <div v-if="monitor.type === 'gamedig'" class="my-3">