diff --git a/WEB-INF/src/controleur/API.java b/WEB-INF/src/controleur/API.java
index 689f2c78bed263a5879f20c7f32d0fa9c08c4390..224bd12dab164170867799000bb6f504e31a96a0 100644
--- a/WEB-INF/src/controleur/API.java
+++ b/WEB-INF/src/controleur/API.java
@@ -1,8 +1,12 @@
 package controleur;
 
-import com.fasterxml.jackson.databind.JavaType;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.List;
+
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+
 import jakarta.servlet.ServletException;
 import jakarta.servlet.annotation.WebServlet;
 import jakarta.servlet.http.HttpServlet;
@@ -14,10 +18,6 @@ import modele.dao.DaoThread;
 import modele.dto.Message;
 import modele.dto.Thread;
 
-import java.io.IOException;
-import java.io.PrintWriter;
-import java.util.List;
-
 @WebServlet("/api/threads/*")
 public class API extends HttpServlet {
     ObjectMapper objectMapper = new ObjectMapper().registerModule(new JavaTimeModule());
diff --git a/WEB-INF/src/modele/dao/DaoMessage.java b/WEB-INF/src/modele/dao/DaoMessage.java
index a3079384badf66aee29e2277d7c37437704f5020..1d350ae882d630d0064401c439c9676b6dfa1de9 100644
--- a/WEB-INF/src/modele/dao/DaoMessage.java
+++ b/WEB-INF/src/modele/dao/DaoMessage.java
@@ -8,7 +8,6 @@ import java.util.ArrayList;
 import java.util.List;
 
 import modele.dto.Message;
-import modele.dto.Thread;
 import utils.DS;
 
 public class DaoMessage {
diff --git a/WEB-INF/vue/signin.jsp b/WEB-INF/vue/signin.jsp
index 75adace2355ad529d3cc1e35c7a14d0e6ba0c7fb..77998178e20416a82137efb03489a70412941b32 100644
--- a/WEB-INF/vue/signin.jsp
+++ b/WEB-INF/vue/signin.jsp
@@ -30,7 +30,7 @@
                     <div>
                         <div class="mt-2 mb-3">
                             <p class="mb-1">Pseudonyme</p>
-                            <input class="form-control" name="username" type="text" placeholder="pmathieu" maxlength="24" required>
+                            <input class="form-control" name="username" pattern="[a-zA-Z0-9_.]{3,24}" type="text" placeholder="pmathieu" maxlength="24" required>
                         </div>
                         <div class="mb-3">
                             <p class="mb-1">Mot de passe</p>