diff --git a/config.go b/config.go
index b330ddc..292fb20 100644
--- a/config.go
+++ b/config.go
@@ -172,6 +172,10 @@ func patchConfig(filename, authorName, authorEmail, summary string, patcher func
 		return errors.Wrap(err, "patching config")
 	}
 
+	if err = cfgFile.runLoadChecks(); err != nil {
+		return errors.Wrap(err, "checking config after patch")
+	}
+
 	return errors.Wrap(
 		writeConfigToYAML(filename, authorName, authorEmail, summary, cfgFile),
 		"replacing config",
diff --git a/configEditor_global.go b/configEditor_global.go
index bd1bbb8..d6819a9 100644
--- a/configEditor_global.go
+++ b/configEditor_global.go
@@ -13,6 +13,7 @@ import (
 
 var frontendReloadHooks = newHooker()
 
+//nolint:funlen // Just contains a collection of objects
 func registerEditorGlobalMethods() {
 	for _, rd := range []plugins.HTTPRouteRegistrationArgs{
 		{
@@ -100,6 +101,23 @@ func registerEditorGlobalMethods() {
 			},
 			ResponseType: plugins.HTTPRouteResponseTypeTextPlain,
 		},
+		{
+			Description: "Validate a template expression against the built in template function library",
+			HandlerFunc: configEditorGlobalValidateTemplate,
+			Method:      http.MethodPut,
+			Module:      "config-editor",
+			Name:        "Validate template expression",
+			Path:        "/validate-template",
+			QueryParams: []plugins.HTTPRouteParamDocumentation{
+				{
+					Description: "The template expression to test",
+					Name:        "template",
+					Required:    true,
+					Type:        "string",
+				},
+			},
+			ResponseType: plugins.HTTPRouteResponseTypeTextPlain,
+		},
 	} {
 		if err := registerRoute(rd); err != nil {
 			log.WithError(err).Fatal("Unable to register config editor route")
@@ -215,3 +233,12 @@ func configEditorGlobalValidateRegex(w http.ResponseWriter, r *http.Request) {
 
 	w.WriteHeader(http.StatusNoContent)
 }
+
+func configEditorGlobalValidateTemplate(w http.ResponseWriter, r *http.Request) {
+	if err := validateTemplate(r.FormValue("template")); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}
diff --git a/src/automessages.vue b/src/automessages.vue
index fe0b336..acb8efb 100644
--- a/src/automessages.vue
+++ b/src/automessages.vue
@@ -124,6 +124,7 @@
               id="formAutoMessageMessage"
               v-model="models.autoMessage.message"
               :state="models.autoMessage.message ? models.autoMessage.message.length <= validateAutoMessageMessageLength : false"
+              @valid-template="valid => updateTemplateValid('autoMessage.message', valid)"
             />
             <div slot="description">
               <font-awesome-icon
@@ -227,6 +228,7 @@
             <template-editor
               id="formAutoMessageDisableOnTemplate"
               v-model="models.autoMessage.disable_on_template"
+              @valid-template="valid => updateTemplateValid('autoMessage.disable_on_template', valid)"
             />
           </b-form-group>
         </b-col>
@@ -284,6 +286,10 @@ export default {
         return false
       }
 
+      if (Object.entries(this.templateValid).filter(e => !e[1]).length > 0) {
+        return false
+      }
+
       return true
     },
 
@@ -344,6 +350,7 @@ export default {
       },
 
       showAutoMessageEditModal: false,
+      templateValid: {},
     }
   },
 
@@ -376,6 +383,7 @@ export default {
         ...msg,
         sendMode: msg.cron ? 'cron' : 'lines',
       })
+      this.templateValid = {}
       this.showAutoMessageEditModal = true
     },
 
@@ -392,6 +400,7 @@ export default {
 
     newAutoMessage() {
       Vue.set(this.models, 'autoMessage', {})
+      this.templateValid = {}
       this.showAutoMessageEditModal = true
     },
 
@@ -422,6 +431,10 @@ export default {
       })
         .catch(err => this.$bus.$emit(constants.NOTIFY_FETCH_ERROR, err))
     },
+
+    updateTemplateValid(id, valid) {
+      Vue.set(this.templateValid, id, valid)
+    },
   },
 
   mounted() {
diff --git a/src/rules.vue b/src/rules.vue
index 083182d..5cf29f0 100644
--- a/src/rules.vue
+++ b/src/rules.vue
@@ -398,6 +398,7 @@
                 <template-editor
                   id="formRuleDisableOnTemplate"
                   v-model="models.rule.disable_on_template"
+                  @valid-template="valid => updateTemplateValid('rule.disable_on_template', valid)"
                 />
               </b-form-group>
             </b-tab>
@@ -603,6 +604,7 @@
                         :id="`${models.rule.uuid}-action-${idx}-${field.key}`"
                         v-model="models.rule.actions[idx].attributes[field.key]"
                         :state="validateActionArgument(idx, field.key)"
+                        @valid-template="valid => updateTemplateValid(`${models.rule.uuid}-action-${idx}-${field.key}`, valid)"
                       />
                     </b-form-group>
 
@@ -781,6 +783,7 @@ export default {
 
       showRuleEditModal: false,
       showRuleSubscribeModal: false,
+      templateValid: {},
       validateReason: null,
     }
   },
@@ -850,6 +853,7 @@ export default {
         cooldown: this.fixDurationRepresentationToString(msg.cooldown),
         user_cooldown: this.fixDurationRepresentationToString(msg.user_cooldown),
       })
+      this.templateValid = {}
       this.showRuleEditModal = true
       this.validateMatcherRegex()
     },
@@ -976,6 +980,7 @@ export default {
 
     newRule() {
       Vue.set(this.models, 'rule', { match_message__validation: true })
+      this.templateValid = {}
       this.showRuleEditModal = true
     },
 
@@ -1094,6 +1099,10 @@ export default {
         .catch(err => this.$bus.$emit(constants.NOTIFY_FETCH_ERROR, err))
     },
 
+    updateTemplateValid(id, valid) {
+      Vue.set(this.templateValid, id, valid)
+    },
+
     validateActionArgument(idx, key) {
       const action = this.models.rule.actions[idx]
       const def = this.getActionDefinitionByType(action.type)
@@ -1189,6 +1198,11 @@ export default {
     },
 
     validateRule() {
+      if (Object.entries(this.templateValid).filter(e => !e[1]).length > 0) {
+        this.validateReason = 'templateValid'
+        return false
+      }
+
       if (!this.models.rule.match_message__validation) {
         this.validateReason = 'rule.match_message__validation'
         return false
diff --git a/src/tplEditor.vue b/src/tplEditor.vue
index f3a6ded..2ac2376 100644
--- a/src/tplEditor.vue
+++ b/src/tplEditor.vue
@@ -1,11 +1,20 @@
 <template>
-  <div :class="wrapClasses">
-    <div ref="editor" />
+  <div>
+    <div :class="wrapClasses">
+      <div ref="editor" />
+    </div>
+    <div
+      v-if="!isValid && validationError"
+      class="d-block invalid-feedback"
+    >
+      {{ validationError }}
+    </div>
   </div>
 </template>
 
 <script>
 import * as constants from './const.js'
+import axios from 'axios'
 import { CodeJar } from 'codejar/codejar.js'
 import Prism from 'prismjs'
 import { withLineNumbers } from 'codejar/linenumbers.js'
@@ -38,8 +47,8 @@ export default {
     wrapClasses() {
       return {
         'form-control': true,
-        'is-invalid': this.state === false,
-        'is-valid': this.state === true,
+        'is-invalid': this.state === false || !this.isValid,
+        'is-valid': this.state === true && this.isValid,
         'template-editor': true,
       }
     },
@@ -48,7 +57,9 @@ export default {
   data() {
     return {
       emittedCode: '',
+      isValid: true,
       jar: null,
+      validationError: '',
     }
   },
 
@@ -57,6 +68,27 @@ export default {
       const code = editor.textContent
       editor.innerHTML = Prism.highlight(code, this.grammar, 'template')
     },
+
+    validateTemplate(template) {
+      if (template === '') {
+        this.isValid = true
+        this.validationError = ''
+        this.$emit('valid-template', true)
+        return
+      }
+
+      return axios.put(`config-editor/validate-template?template=${encodeURIComponent(template)}`)
+        .then(() => {
+          this.isValid = true
+          this.validationError = ''
+          this.$emit('valid-template', true)
+        })
+        .catch(resp => {
+          this.isValid = false
+          this.validationError = resp.response.data.split(':1:')[1]
+          this.$emit('valid-template', false)
+        })
+    },
   },
 
   mounted() {
@@ -65,6 +97,7 @@ export default {
       tab: ' '.repeat(2),
     })
     this.jar.onUpdate(code => {
+      this.validateTemplate(code)
       this.emittedCode = code
       this.$emit('input', code)
     })
@@ -101,8 +134,6 @@ export default {
 
 <style>
 .template-editor {
-  background-color: #fff;
-  border-radius: 0.25rem;
   color: #444;
   font-family: SFMono-Regular,Menlo,Monaco,Consolas,"Liberation Mono","Courier New",monospace;
   font-size: 87.5%;
@@ -110,6 +141,11 @@ export default {
   padding: 0;
 }
 
+.template-editor .codejar-wrap {
+  background-color: #fff;
+  border-radius: 0.25rem;
+}
+
 .template-editor .codejar-linenumbers {
   padding-right: 0.5em;
   text-align: right;