diff --git a/src/main/java/aromanticcat/umcproject/entity/Member.java b/src/main/java/aromanticcat/umcproject/entity/Member.java
index 30dba2d..5fa3b1b 100644
--- a/src/main/java/aromanticcat/umcproject/entity/Member.java
+++ b/src/main/java/aromanticcat/umcproject/entity/Member.java
@@ -1,18 +1,17 @@
 package aromanticcat.umcproject.entity;
 
+import lombok.*;
+
+import javax.persistence.*;
 import java.util.ArrayList;
 import java.util.List;
-import javax.persistence.CascadeType;
-import javax.persistence.Entity;
-import javax.persistence.FetchType;
-import javax.persistence.GeneratedValue;
-import javax.persistence.GenerationType;
-import javax.persistence.Id;
-import javax.persistence.OneToMany;
-import lombok.Getter;
 
 @Entity
 @Getter
+@Builder
+@AllArgsConstructor
+@NoArgsConstructor
+@ToString
 public class Member extends BaseEntity {
 
     @Id
diff --git a/src/main/java/aromanticcat/umcproject/entity/NangmanLetter.java b/src/main/java/aromanticcat/umcproject/entity/NangmanLetter.java
index d1cebe5..4a9325c 100644
--- a/src/main/java/aromanticcat/umcproject/entity/NangmanLetter.java
+++ b/src/main/java/aromanticcat/umcproject/entity/NangmanLetter.java
@@ -1,41 +1,46 @@
 package aromanticcat.umcproject.entity;
 
-import javax.persistence.Entity;
-import javax.persistence.FetchType;
-import javax.persistence.GeneratedValue;
-import javax.persistence.GenerationType;
-import javax.persistence.Id;
-import javax.persistence.JoinColumn;
-import javax.persistence.ManyToOne;
-import lombok.Getter;
+import lombok.*;
+
+import javax.persistence.*;
+import javax.validation.constraints.NotNull;
 
 @Entity
 @Getter
+@Builder
+@AllArgsConstructor
+@NoArgsConstructor
+@ToString
 public class NangmanLetter extends BaseEntity {
 
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private Long id;
 
+    @NotNull
     private String sender_nickname;
 
-    private boolean is_public;
+    @NotNull
+    private Boolean is_public;
 
+    @NotNull
     private String content;
 
-    private boolean has_response;
+    @NotNull
+    @Builder.Default
+    private Boolean has_response = false;
 
-    private int thumbs_up_cnt;
+    private Integer thumbs_up_cnt;
 
-    private int heart_cnt;
+    private Integer heart_cnt;
 
-    private int crying_cnt;
+    private Integer crying_cnt;
 
-    private int clover_cnt;
+    private Integer clover_cnt;
 
-    private int clap_cnt;
+    private Integer clap_cnt;
 
-    private int star_cnt;
+    private Integer star_cnt;
 
     @JoinColumn(name = "member_id")
     @ManyToOne(fetch = FetchType.LAZY)