diff --git a/src/main/resources/messages/messages.properties b/src/main/resources/messages/messages.properties
index 2d779d3c3..7b8b5dfd8 100644
--- a/src/main/resources/messages/messages.properties
+++ b/src/main/resources/messages/messages.properties
@@ -31,3 +31,18 @@ pets=Pets
 home=Home
 error=Error
 telephone.invalid=Telephone must be a 10-digit number
+layoutTitle=PetClinic :: a Spring Framework demonstration
+pet=Pet
+birthDate=Birth Date
+type=Type
+previousVisits=Previous Visits
+date=Date
+description=Description
+new=New 
+addVisit=Add Visit
+editPet=Edit Pet
+ownerInformation=Owner Information
+visitDate=Visit Date
+editOwner=Edit Owner
+addNewPet=Add New Pet
+petsAndVisits=Pets and Visits
diff --git a/src/main/resources/messages/messages_de.properties b/src/main/resources/messages/messages_de.properties
index f87ab62b2..8d208410c 100644
--- a/src/main/resources/messages/messages_de.properties
+++ b/src/main/resources/messages/messages_de.properties
@@ -31,3 +31,18 @@ pets=Haustiere
 home=Startseite
 error=Fehler
 telephone.invalid=Telefonnummer muss aus 10 Ziffern bestehen
+layoutTitle=PetClinic :: eine Demonstration des Spring Frameworks
+pet=Haustier
+birthDate=Geburtsdatum
+type=Typ
+previousVisits=Frühere Besuche
+date=Datum
+description=Beschreibung
+new=Neu
+addVisit=Besuch hinzufügen
+editPet=Haustier bearbeiten
+ownerInformation=Besitzerinformationen
+visitDate=Besuchsdatum
+editOwner=Besitzer bearbeiten
+addNewPet=Neues Haustier hinzufügen
+petsAndVisits=Haustiere und Besuche
diff --git a/src/main/resources/messages/messages_es.properties b/src/main/resources/messages/messages_es.properties
index 5535dfb7a..91d5c9ebd 100644
--- a/src/main/resources/messages/messages_es.properties
+++ b/src/main/resources/messages/messages_es.properties
@@ -31,3 +31,18 @@ pets=Mascotas
 home=Inicio
 error=Error
 telephone.invalid=El número de teléfono debe tener 10 dígitos
+layoutTitle=PetClinic :: una demostración de Spring Framework
+pet=Mascota
+birthDate=Fecha de nacimiento
+type=Tipo
+previousVisits=Visitas anteriores
+date=Fecha
+description=Descripción
+new=Nuevo
+addVisit=Agregar visita
+editPet=Editar mascota
+ownerInformation=Información del propietario
+visitDate=Fecha de visita
+editOwner=Editar propietario
+addNewPet=Agregar nueva mascota
+petsAndVisits=Mascotas y visitas
diff --git a/src/main/resources/messages/messages_fa.properties b/src/main/resources/messages/messages_fa.properties
index b71466c14..2566b8949 100644
--- a/src/main/resources/messages/messages_fa.properties
+++ b/src/main/resources/messages/messages_fa.properties
@@ -31,3 +31,18 @@ pets=حیوانات خانگی
 home=خانه
 error=خطا
 telephone.invalid=شماره تلفن باید ۱۰ رقمی باشد
+layoutTitle=PetClinic :: یک نمایش از Spring Framework
+pet=حیوان خانگی
+birthDate=تاریخ تولد
+type=نوع
+previousVisits=ویزیت‌های قبلی
+date=تاریخ
+description=توضیحات
+new=جدید
+addVisit=افزودن ویزیت
+editPet=ویرایش حیوان خانگی
+ownerInformation=اطلاعات مالک
+visitDate=تاریخ ویزیت
+editOwner=ویرایش مالک
+addNewPet=افزودن حیوان خانگی جدید
+petsAndVisits=حیوانات و ویزیت‌ها
diff --git a/src/main/resources/messages/messages_ko.properties b/src/main/resources/messages/messages_ko.properties
index a1a8b14cd..ca3ae5a05 100644
--- a/src/main/resources/messages/messages_ko.properties
+++ b/src/main/resources/messages/messages_ko.properties
@@ -31,3 +31,18 @@ pets=반려동물
 home=홈
 error=오류
 telephone.invalid=전화번호는 10자리 숫자여야 합니다
+layoutTitle=PetClinic :: Spring Framework 데모
+pet=반려동물
+birthDate=생년월일
+type=종류
+previousVisits=이전 방문
+date=날짜
+description=설명
+new=새로운
+addVisit=방문 추가
+editPet=반려동물 수정
+ownerInformation=소유자 정보
+visitDate=방문 날짜
+editOwner=소유자 수정
+addNewPet=새 반려동물 추가
+petsAndVisits=반려동물 및 방문
diff --git a/src/main/resources/messages/messages_pt.properties b/src/main/resources/messages/messages_pt.properties
index 13c442e5c..03f5cd531 100644
--- a/src/main/resources/messages/messages_pt.properties
+++ b/src/main/resources/messages/messages_pt.properties
@@ -31,3 +31,18 @@ pets=Animais de estimação
 home=Início
 error=Erro
 telephone.invalid=O número de telefone deve conter 10 dígitos
+layoutTitle=PetClinic :: uma demonstração do Spring Framework
+pet=Animal de estimação
+birthDate=Data de nascimento
+type=Tipo
+previousVisits=Visitas anteriores
+date=Data
+description=Descrição
+new=Novo
+addVisit=Adicionar visita
+editPet=Editar animal
+ownerInformation=Informações do proprietário
+visitDate=Data da visita
+editOwner=Editar proprietário
+addNewPet=Adicionar novo animal
+petsAndVisits=Animais e visitas
diff --git a/src/main/resources/messages/messages_ru.properties b/src/main/resources/messages/messages_ru.properties
index 835fd0430..b9ed998be 100644
--- a/src/main/resources/messages/messages_ru.properties
+++ b/src/main/resources/messages/messages_ru.properties
@@ -31,3 +31,18 @@ pets=Питомцы
 home=Главная
 error=Ошибка
 telephone.invalid=Телефон должен содержать 10 цифр
+layoutTitle=PetClinic :: демонстрация Spring Framework
+pet=Питомец
+birthDate=Дата рождения
+type=Тип
+previousVisits=Предыдущие визиты
+date=Дата
+description=Описание
+new=Новый
+addVisit=Добавить визит
+editPet=Редактировать питомца
+ownerInformation=Информация о владельце
+visitDate=Дата визита
+editOwner=Редактировать владельца
+addNewPet=Добавить нового питомца
+petsAndVisits=Питомцы и визиты
diff --git a/src/main/resources/messages/messages_tr.properties b/src/main/resources/messages/messages_tr.properties
index 45f86c3d5..ff9ffdabd 100644
--- a/src/main/resources/messages/messages_tr.properties
+++ b/src/main/resources/messages/messages_tr.properties
@@ -31,3 +31,18 @@ pets=Evcil Hayvanlar
 home=Ana Sayfa
 error=Hata
 telephone.invalid=Telefon numarası 10 basamaklı olmalıdır
+layoutTitle=PetClinic :: bir Spring Framework demosu
+pet=Evcil Hayvan
+birthDate=Doğum Tarihi
+type=Tür
+previousVisits=Önceki Ziyaretler
+date=Tarih
+description=Açıklama
+new=Yeni
+addVisit=Ziyaret Ekle
+editPet=Evcil Hayvanı Düzenle
+ownerInformation=Sahip Bilgileri
+visitDate=Ziyaret Tarihi
+editOwner=Sahibi Düzenle
+addNewPet=Yeni Evcil Hayvan Ekle
+petsAndVisits=Evcil Hayvanlar ve Ziyaretler
diff --git a/src/main/resources/templates/fragments/inputField.html b/src/main/resources/templates/fragments/inputField.html
index de456d250..68afbec7a 100644
--- a/src/main/resources/templates/fragments/inputField.html
+++ b/src/main/resources/templates/fragments/inputField.html
@@ -1,4 +1,4 @@
-<html>
+<html xmlns:th="https://www.thymeleaf.org">
 <body>
   <form>
     <th:block th:fragment="input (label, name, type)">
@@ -18,7 +18,7 @@
             <span
               class="fa fa-remove form-control-feedback"
               aria-hidden="true"></span>
-            <span class="help-inline" th:errors="*{__${name}__}">Error</span>
+            <span class="help-inline" th:errors="*{__${name}__}" th:text="#{error}">Error</span>
           </th:block>
         </div>
       </div>
diff --git a/src/main/resources/templates/fragments/layout.html b/src/main/resources/templates/fragments/layout.html
index e0d82b003..34e0a5496 100644
--- a/src/main/resources/templates/fragments/layout.html
+++ b/src/main/resources/templates/fragments/layout.html
@@ -1,5 +1,6 @@
 <!doctype html>
-<html th:fragment="layout (template, menu)">
+<html th:fragment="layout (template, menu)"
+      xmlns:th="https://www.thymeleaf.org">
 
 <head>
 
@@ -10,7 +11,7 @@
 
   <link rel="shortcut icon" type="image/x-icon" th:href="@{/resources/images/favicon.png}">
 
-  <title>PetClinic :: a Spring Framework demonstration</title>
+  <title th:text="#{layoutTitle}">PetClinic :: a Spring Framework demonstration</title>
 
   <!--[if lt IE 9]>
     <script src="https://oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
diff --git a/src/main/resources/templates/fragments/selectField.html b/src/main/resources/templates/fragments/selectField.html
index 1e1212d09..b90004ef8 100644
--- a/src/main/resources/templates/fragments/selectField.html
+++ b/src/main/resources/templates/fragments/selectField.html
@@ -1,4 +1,4 @@
-<html>
+<html xmlns:th="https://www.thymeleaf.org">
 <body>
   <form>
     <th:block th:fragment="select (label, name, items)">
@@ -19,7 +19,7 @@
             <span
               class="fa fa-remove form-control-feedback"
               aria-hidden="true"></span>
-            <span class="help-inline" th:errors="*{__${name}__}">Error</span>
+            <span class="help-inline" th:errors="*{__${name}__}" th:text="#{error}">Error</span>
           </th:block>
         </div>
       </div>
diff --git a/src/main/resources/templates/owners/findOwners.html b/src/main/resources/templates/owners/findOwners.html
index 682bc103e..61536ae9b 100644
--- a/src/main/resources/templates/owners/findOwners.html
+++ b/src/main/resources/templates/owners/findOwners.html
@@ -12,10 +12,12 @@
         <label class="col-sm-2 control-label" th:text="#{lastName}">Last name </label>
         <div class="col-sm-10">
           <input class="form-control" th:field="*{lastName}" size="30"
-            maxlength="80" /> <span class="help-inline"><div
-              th:if="${#fields.hasAnyErrors()}">
-              <p th:each="err : ${#fields.allErrors()}" th:text="${err}">Error</p>
-            </div></span>
+            maxlength="80" />
+          <span class="help-inline">
+            <div th:if="${#fields.hasAnyErrors()}">
+                <p th:each="err : ${#fields.allErrors()}" th:text="${err}">Error</p>
+            </div>
+          </span>
         </div>
       </div>
     </div>
diff --git a/src/main/resources/templates/owners/ownerDetails.html b/src/main/resources/templates/owners/ownerDetails.html
index 15bca4ad2..abdc7a3d8 100644
--- a/src/main/resources/templates/owners/ownerDetails.html
+++ b/src/main/resources/templates/owners/ownerDetails.html
@@ -6,7 +6,7 @@
   <body>
   
   
-    <h2>Owner Information</h2>
+    <h2 th:text="#{ownerInformation}">Owner Information</h2>
 
     <div th:if="${message}" class="alert alert-success" id="success-message">
       <span th:text="${message}"></span>
@@ -21,44 +21,44 @@
 
     <table class="table table-striped" th:object="${owner}">
       <tr>
-        <th>Name</th>
+        <th th:text="#{name}">Name</th>
         <td><b th:text="*{firstName + ' ' + lastName}"></b></td>
       </tr>
       <tr>
-        <th>Address</th>
+        <th th:text="#{address}">Address</th>
         <td th:text="*{address}"></td>
       </tr>
       <tr>
-        <th>City</th>
+        <th th:text="#{city}">City</th>
         <td th:text="*{city}"></td>
       </tr>
       <tr>
-        <th>Telephone</th>
+        <th th:text="#{telephone}">Telephone</th>
         <td th:text="*{telephone}"></td>
       </tr>
     </table>
   
-    <a th:href="@{__${owner.id}__/edit}" class="btn btn-primary">Edit
+    <a th:href="@{__${owner.id}__/edit}" class="btn btn-primary"  th:text="#{editOwner}">Edit
       Owner</a>
-    <a th:href="@{__${owner.id}__/pets/new}" class="btn btn-primary">Add
+    <a th:href="@{__${owner.id}__/pets/new}" class="btn btn-primary" th:text="#{addNewPet}">Add
       New Pet</a>
   
     <br />
     <br />
     <br />
-    <h2>Pets and Visits</h2>
+    <h2 th:text="#{petsAndVisits}">Pets and Visits</h2>
   
     <table class="table table-striped">
   
       <tr th:each="pet : ${owner.pets}">
         <td valign="top">
           <dl class="dl-horizontal">
-            <dt>Name</dt>
+            <dt th:text="#{name}">Name</dt>
             <dd th:text="${pet.name}"></dd>
-            <dt>Birth Date</dt>
+            <dt  th:text="#{birthDate}">Birth Date</dt>
             <dd
               th:text="${#temporals.format(pet.birthDate, 'yyyy-MM-dd')}"></dd>
-            <dt>Type</dt>
+            <dt th:text="#{type}">Type</dt>
             <dd th:text="${pet.type}"></dd>
           </dl>
         </td>
@@ -66,8 +66,8 @@
           <table class="table-condensed">
             <thead>
               <tr>
-                <th>Visit Date</th>
-                <th>Description</th>
+                <th th:text="#{visitDate}">Visit Date</th>
+                <th th:text="#{description}">Description</th>
               </tr>
             </thead>
             <tr th:each="visit : ${pet.visits}">
@@ -75,8 +75,8 @@
               <td th:text="${visit?.description}"></td>
             </tr>
             <tr>
-              <td><a th:href="@{__${owner.id}__/pets/__${pet.id}__/edit}">Edit Pet</a></td>
-              <td><a th:href="@{__${owner.id}__/pets/__${pet.id}__/visits/new}">Add Visit</a></td>
+              <td><a th:href="@{__${owner.id}__/pets/__${pet.id}__/edit}" th:text="#{editPet}">Edit Pet</a></td>
+              <td><a th:href="@{__${owner.id}__/pets/__${pet.id}__/visits/new}" th:text="#{addVisit}">Add Visit</a></td>
             </tr>
           </table>
         </td>
diff --git a/src/main/resources/templates/owners/ownersList.html b/src/main/resources/templates/owners/ownersList.html
index 2ff13349c..45843f6a7 100644
--- a/src/main/resources/templates/owners/ownersList.html
+++ b/src/main/resources/templates/owners/ownersList.html
@@ -37,24 +37,24 @@
     </span>
   <span>]&nbsp;</span>
   <span>
-      <a th:if="${currentPage > 1}" th:href="@{'/owners?page=1'}" title="First"
+      <a th:if="${currentPage > 1}" th:href="@{'/owners?page=1'}" th:title="#{first}"
          class="fa fa-fast-backward"></a>
-      <span th:unless="${currentPage > 1}" title="First" class="fa fa-fast-backward"></span>
+      <span th:unless="${currentPage > 1}" th:title="#{first}" class="fa fa-fast-backward"></span>
     </span>
   <span>
-      <a th:if="${currentPage > 1}" th:href="@{'/owners?page=__${currentPage - 1}__'}" title="Previous"
+      <a th:if="${currentPage > 1}" th:href="@{'/owners?page=__${currentPage - 1}__'}" th:title="#{previous}"
          class="fa fa-step-backward"></a>
-      <span th:unless="${currentPage > 1}" title="Previous" class="fa fa-step-backward"></span>
+      <span th:unless="${currentPage > 1}" th:title="#{previous}" class="fa fa-step-backward"></span>
     </span>
   <span>
-      <a th:if="${currentPage < totalPages}" th:href="@{'/owners?page=__${currentPage + 1}__'}" title="Next"
+      <a th:if="${currentPage < totalPages}" th:href="@{'/owners?page=__${currentPage + 1}__'}" th:title="#{next}"
          class="fa fa-step-forward"></a>
-      <span th:unless="${currentPage < totalPages}" title="Next" class="fa fa-step-forward"></span>
+      <span th:unless="${currentPage < totalPages}" th:title="#{next}" class="fa fa-step-forward"></span>
     </span>
   <span>
-      <a th:if="${currentPage < totalPages}" th:href="@{'/owners?page=__${totalPages}__'}" title="Last"
+      <a th:if="${currentPage < totalPages}" th:href="@{'/owners?page=__${totalPages}__'}" th:title="#{last}"
          class="fa fa-fast-forward"></a>
-      <span th:unless="${currentPage < totalPages}" title="Last" class="fa fa-step-forward"></span>
+      <span th:unless="${currentPage < totalPages}" th:title="#{last}" class="fa fa-step-forward"></span>
     </span>
 </div>
 </body>
diff --git a/src/main/resources/templates/pets/createOrUpdatePetForm.html b/src/main/resources/templates/pets/createOrUpdatePetForm.html
index dd8a4dd1c..b1d300a6f 100644
--- a/src/main/resources/templates/pets/createOrUpdatePetForm.html
+++ b/src/main/resources/templates/pets/createOrUpdatePetForm.html
@@ -4,14 +4,14 @@
 <body>
 
   <h2>
-    <th:block th:if="${pet['new']}">New </th:block>
-    Pet
+    <th:block th:if="${pet['new']}" th:text="#{new}">New </th:block>
+    <span th:text="#{pet}">Pet</span>
   </h2>
   <form th:object="${pet}" class="form-horizontal" method="post">
     <input type="hidden" name="id" th:value="*{id}" />
     <div class="form-group has-feedback">
       <div class="form-group">
-        <label class="col-sm-2 control-label">Owner</label>
+        <label class="col-sm-2 control-label" th:text="#{owner}">Owner</label>
         <div class="col-sm-10">
           <span th:text="${owner?.firstName + ' ' + owner?.lastName}" />
         </div>
@@ -27,8 +27,7 @@
       <div class="col-sm-offset-2 col-sm-10">
         <button
           th:with="text=${pet['new']} ? 'Add Pet' : 'Update Pet'"
-          class="btn btn-primary" type="submit" th:text="${text}">Add
-          Pet</button>
+          class="btn btn-primary" type="submit" th:text="${text}">Add Pet</button>
       </div>
     </div>
   </form>
diff --git a/src/main/resources/templates/pets/createOrUpdateVisitForm.html b/src/main/resources/templates/pets/createOrUpdateVisitForm.html
index 4b0d315f0..20e102fa6 100644
--- a/src/main/resources/templates/pets/createOrUpdateVisitForm.html
+++ b/src/main/resources/templates/pets/createOrUpdateVisitForm.html
@@ -4,18 +4,18 @@
 <body>
 
   <h2>
-    <th:block th:if="${visit['new']}">New </th:block>
+    <th:block th:if="${visit['new']}" th:text="#{new}">New </th:block>
     Visit
   </h2>
 
-  <b>Pet</b>
+  <b th:text="#{pet}">Pet</b>
   <table class="table table-striped">
     <thead>
       <tr>
-        <th>Name</th>
-        <th>Birth Date</th>
-        <th>Type</th>
-        <th>Owner</th>
+        <th th:text="#{name}">Name</th>
+        <th th:text="#{birthDate}">Birth Date</th>
+        <th th:text="#{type}">Type</th>
+        <th th:text="#{owner}">Owner</th>
       </tr>
     </thead>
     <tr>
@@ -39,17 +39,17 @@
     <div class="form-group">
       <div class="col-sm-offset-2 col-sm-10">
         <input type="hidden" name="petId" th:value="${pet.id}" />
-        <button class="btn btn-primary" type="submit">Add Visit</button>
+        <button class="btn btn-primary" type="submit" th:text="${addVisit}">Add Visit</button>
       </div>
     </div>
   </form>
 
   <br />
-  <b>Previous Visits</b>
+  <b th:text="#{previousVisits}">Previous Visits</b>
   <table class="table table-striped">
     <tr>
-      <th>Date</th>
-      <th>Description</th>
+      <th th:text="#{date}">Date</th>
+      <th th:text="#{description}">Description</th>
     </tr>
     <tr th:if="${!visit['new']}" th:each="visit : ${pet.visits}">
       <td th:text="${#temporals.format(visit.date, 'yyyy-MM-dd')}"></td>
diff --git a/src/main/resources/templates/vets/vetList.html b/src/main/resources/templates/vets/vetList.html
index 10a9efb04..8d51c1e89 100644
--- a/src/main/resources/templates/vets/vetList.html
+++ b/src/main/resources/templates/vets/vetList.html
@@ -33,22 +33,22 @@
     </span>
   <span>]&nbsp;</span>
   <span>
-      <a th:if="${currentPage > 1}" th:href="@{'/vets.html?page=1'}" title=#{first}
+      <a th:if="${currentPage > 1}" th:href="@{'/vets.html?page=1'}" th:title="#{first}"
          class="fa fa-fast-backward"></a>
-      <span th:unless="${currentPage > 1}" th:text="#{first}" title=#{first} class="fa fa-fast-backward"></span>
+      <span th:unless="${currentPage > 1}" th:text="#{first}" th:title="#{first}" class="fa fa-fast-backward"></span>
     </span>
   <span>
-      <a th:if="${currentPage > 1}" th:href="@{'/vets.html?page=__${currentPage - 1}__'}" title=#{previous}
+      <a th:if="${currentPage > 1}" th:href="@{'/vets.html?page=__${currentPage - 1}__'}" th:title="#{previous}"
          class="fa fa-step-backward"></a>
-      <span th:unless="${currentPage > 1}" th:text="#{previous}" title=#{previous} class="fa fa-step-backward"></span>
+      <span th:unless="${currentPage > 1}" th:text="#{previous}" th:title="#{previous}" class="fa fa-step-backward"></span>
     </span>
   <span>
-      <a th:if="${currentPage < totalPages}" th:href="@{'/vets.html?page=__${currentPage + 1}__'}" title=#{next}
+      <a th:if="${currentPage < totalPages}" th:href="@{'/vets.html?page=__${currentPage + 1}__'}" th:title="#{next}"
          class="fa fa-step-forward"></a>
-      <span th:unless="${currentPage < totalPages}" th:text="#{next}" title=#{next} class="fa fa-step-forward"></span>
+      <span th:unless="${currentPage < totalPages}" th:text="#{next}" th:title="#{next}" class="fa fa-step-forward"></span>
     </span>
   <span>
-      <a th:if="${currentPage < totalPages}" th:href="@{'/vets.html?page=__${totalPages}__'}" title=#{last}
+      <a th:if="${currentPage < totalPages}" th:href="@{'/vets.html?page=__${totalPages}__'}" th:title="#{last}"
          class="fa fa-fast-forward"></a>
       <span th:unless="${currentPage < totalPages}" th:text="#{last}" class="fa fa-fast-forward"></span>
     </span>
diff --git a/src/test/java/org/springframework/samples/petclinic/system/I18nPropertiesSyncTest.java b/src/test/java/org/springframework/samples/petclinic/system/I18nPropertiesSyncTest.java
new file mode 100644
index 000000000..fec159cec
--- /dev/null
+++ b/src/test/java/org/springframework/samples/petclinic/system/I18nPropertiesSyncTest.java
@@ -0,0 +1,136 @@
+package org.springframework.samples.petclinic.system;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.nio.file.*;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.regex.Pattern;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.fail;
+
+/**
+ * This test ensures that there are no hard-coded strings without internationalization in
+ * any HTML files. Also ensures that a string is translated in every language to avoid
+ * partial translations.
+ *
+ * @author Anuj Ashok Potdar
+ */
+public class I18nPropertiesSyncTest {
+
+	private static final String I18N_DIR = "src/main/resources";
+
+	private static final String BASE_NAME = "messages";
+
+	public static final String PROPERTIES = ".properties";
+
+	private static final Pattern HTML_TEXT_LITERAL = Pattern.compile(">([^<>{}]+)<");
+
+	private static final Pattern BRACKET_ONLY = Pattern.compile("<[^>]*>\\s*[\\[\\]](?:&nbsp;)?\\s*</[^>]*>");
+
+	private static final Pattern HAS_TH_TEXT_ATTRIBUTE = Pattern.compile("th:(u)?text\\s*=\\s*\"[^\"]+\"");
+
+	@Test
+	public void checkNonInternationalizedStrings() throws IOException {
+		Path root = Paths.get("src/main");
+		List<Path> files;
+
+		try (Stream<Path> stream = Files.walk(root)) {
+			files = stream.filter(p -> p.toString().endsWith(".java") || p.toString().endsWith(".html"))
+				.filter(p -> !p.toString().contains("/test/"))
+				.filter(p -> !p.getFileName().toString().endsWith("Test.java"))
+				.toList();
+		}
+
+		StringBuilder report = new StringBuilder();
+
+		for (Path file : files) {
+			List<String> lines = Files.readAllLines(file);
+			for (int i = 0; i < lines.size(); i++) {
+				String line = lines.get(i).trim();
+
+				if (line.startsWith("//") || line.startsWith("@") || line.contains("log.")
+						|| line.contains("System.out"))
+					continue;
+
+				if (file.toString().endsWith(".html")) {
+					boolean hasLiteralText = HTML_TEXT_LITERAL.matcher(line).find();
+					boolean hasThTextAttribute = HAS_TH_TEXT_ATTRIBUTE.matcher(line).find();
+					boolean isBracketOnly = BRACKET_ONLY.matcher(line).find();
+
+					if (hasLiteralText && !line.contains("#{") && !hasThTextAttribute && !isBracketOnly) {
+						report.append("HTML: ")
+							.append(file)
+							.append(" Line ")
+							.append(i + 1)
+							.append(": ")
+							.append(line)
+							.append("\n");
+					}
+				}
+			}
+		}
+
+		if (!report.isEmpty()) {
+			fail("Hardcoded (non-internationalized) strings found:\n" + report);
+		}
+	}
+
+	@Test
+	public void checkI18nPropertyFilesAreInSync() throws IOException {
+		List<Path> propertyFiles;
+		try (Stream<Path> stream = Files.walk(Paths.get(I18N_DIR))) {
+			propertyFiles = stream.filter(p -> p.getFileName().toString().startsWith(BASE_NAME))
+				.filter(p -> p.getFileName().toString().endsWith(PROPERTIES))
+				.toList();
+		}
+
+		Map<String, Properties> localeToProps = new HashMap<>();
+
+		for (Path path : propertyFiles) {
+			Properties props = new Properties();
+			try (var reader = Files.newBufferedReader(path)) {
+				props.load(reader);
+				localeToProps.put(path.getFileName().toString(), props);
+			}
+		}
+
+		String baseFile = BASE_NAME + PROPERTIES;
+		Properties baseProps = localeToProps.get(baseFile);
+		if (baseProps == null) {
+			fail("Base properties file '" + baseFile + "' not found.");
+			return;
+		}
+
+		Set<String> baseKeys = baseProps.stringPropertyNames();
+		StringBuilder report = new StringBuilder();
+
+		for (Map.Entry<String, Properties> entry : localeToProps.entrySet()) {
+			String fileName = entry.getKey();
+			// We use fallback logic to include english strings, hence messages_en is not
+			// populated.
+			if (fileName.equals(baseFile) || fileName.equals("messages_en.properties"))
+				continue;
+
+			Properties props = entry.getValue();
+			Set<String> missingKeys = new TreeSet<>(baseKeys);
+			missingKeys.removeAll(props.stringPropertyNames());
+
+			if (!missingKeys.isEmpty()) {
+				report.append("Missing keys in ").append(fileName).append(":\n");
+				missingKeys.forEach(k -> report.append("  ").append(k).append("\n"));
+			}
+		}
+
+		if (!report.isEmpty()) {
+			fail("Translation files are not in sync:\n" + report);
+		}
+	}
+
+}