diff --git a/internal/howmuch/model/event.go b/internal/howmuch/model/event.go
index ecd866b..f2ded61 100644
--- a/internal/howmuch/model/event.go
+++ b/internal/howmuch/model/event.go
@@ -24,16 +24,39 @@ package model
 
 import "time"
 
-type Event struct {
+type EventCreateDTO struct {
+	Name        string `json:"name"        binding:"requiered"`
+	Description string `json:"description"`
+	OwnerID     int    `json:"owner_id"    binding:"requiered,number"`
+}
+
+type EventPO struct {
 	ID int
 
 	Name            string
 	Description     string
-	Users           []*User
-	Expenses        []*Expense
-	TotalAmount     Money
-	DefaultCurrency Currency
-	CreatedBy       User
+	TotalAmount     int
+	DefaultCurrency string
+	OwnerID         int
+
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}
+
+type Event struct {
+	ID int
+
+	Name        string
+	Description string
+
+	// lazy get using participation join
+	Users []*User
+	// lazy get
+	Expenses []*Expense
+
+	TotalAmount     Money
+	DefaultCurrency Currency
+	Owner           User
 
 	CreatedAt time.Time
 	UpdatedAt time.Time
diff --git a/internal/howmuch/model/expense.go b/internal/howmuch/model/expense.go
index 7515fad..6f6c091 100644
--- a/internal/howmuch/model/expense.go
+++ b/internal/howmuch/model/expense.go
@@ -24,20 +24,47 @@ package model
 
 import "time"
 
-type ExpenseDetail struct {
+type ExpenseDTO struct {
+	Amount       Money         `json:"money"         binding:"required,number"`
+	PayerIDs     []int         `json:"payer_ids"     binding:"required"`
+	RecipientIDs []int         `json:"recipient_ids" binding:"required"`
+	EventID      int           `json:"event_id"      binding:"required"`
+	Detail       ExpenseDetail `json:"detail"`
+}
+
+type ExpensePO struct {
+	ID int
+
+	Amount   int
+	Currency string
+	EventID  int
+
+	// ExpenseDetail
 	Name  string
 	Place string
+
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}
+
+type ExpenseDetail struct {
+	Name  string `json:"name"`
+	Place string `json:"place"`
 }
 
 type Expense struct {
 	ID int
 
-	Amount       Money
-	Currency     Currency
-	PayerIDs     []int
+	Amount Money
+
+	// Lazy aggregate using Transaction join
+	PayerIDs []int
+
+	// Lazy aggregate using Transaction join
 	RecipientIDs []int
-	EventID      int
-	Detail       ExpenseDetail
+
+	EventID int
+	Detail  ExpenseDetail
 
 	CreatedAt time.Time
 	UpdatedAt time.Time
diff --git a/internal/howmuch/model/money.go b/internal/howmuch/model/money.go
index 61d052f..b2f37d7 100644
--- a/internal/howmuch/model/money.go
+++ b/internal/howmuch/model/money.go
@@ -36,8 +36,8 @@ const (
 )
 
 type Money struct {
-	ammount  int
-	currency Currency
+	Amount   int      `json:"amount"   binding:"required,number"`
+	Currency Currency `json:"currency" binding:"required"`
 }
 
 func MakeMoney(amount int, currency Currency) Money {
@@ -46,10 +46,10 @@ func MakeMoney(amount int, currency Currency) Money {
 
 func Add(cur Currency, money ...Money) Money {
 	var sum Money
-	sum.currency = cur
+	sum.Currency = cur
 
 	for _, m := range money {
-		sum.ammount += m.ammount
+		sum.Amount += m.Amount
 	}
 
 	return sum
@@ -58,9 +58,9 @@ func Add(cur Currency, money ...Money) Money {
 func Diff(cur Currency, money1 Money, money2 Money) Money {
 	var diff Money
 
-	diff.currency = cur
+	diff.Currency = cur
 
-	diff.ammount = money1.ammount - money2.ammount
+	diff.Amount = money1.Amount - money2.Amount
 
 	return diff
 }
diff --git a/internal/howmuch/model/participation.go b/internal/howmuch/model/participation.go
index 1f215d4..c2a25b4 100644
--- a/internal/howmuch/model/participation.go
+++ b/internal/howmuch/model/participation.go
@@ -24,6 +24,8 @@ package model
 
 import "time"
 
+type ParticipationPO Participation
+
 // Participation is the association between Users and Events
 type Participation struct {
 	ID int
diff --git a/internal/howmuch/model/transaction.go b/internal/howmuch/model/transaction.go
index 8f0fada..31ec8f5 100644
--- a/internal/howmuch/model/transaction.go
+++ b/internal/howmuch/model/transaction.go
@@ -24,14 +24,17 @@ package model
 
 import "time"
 
+type TransactionPO Transaction
+
 // Transaction is the association between Expenses and Users
 type Transaction struct {
 	ID int
 
 	ExpenseID Expense
-	PayerID   int
-	Amount    Money
-	Currency  Currency
+	UserID    int
+	Amount    int
+	Currency  string
+	IsIncome  bool
 
 	CreatedAt time.Time
 	UpdatedAt time.Time
diff --git a/internal/howmuch/model/user.go b/internal/howmuch/model/user.go
index c6e7fd8..1e02ea2 100644
--- a/internal/howmuch/model/user.go
+++ b/internal/howmuch/model/user.go
@@ -36,8 +36,7 @@ type UserExistDTO struct {
 	Password string `json:"password" binding:"required"`
 }
 
-// User model
-type User struct {
+type UserPO struct {
 	ID int
 
 	Email     string
@@ -48,3 +47,19 @@ type User struct {
 	CreatedAt time.Time
 	UpdatedAt time.Time
 }
+
+// User model
+type User struct {
+	ID int
+
+	Email     string
+	FirstName string
+	LastName  string
+	Password  string
+
+	// Lazy aggregate with the Participation join
+	EventIDs []int
+
+	CreatedAt time.Time
+	UpdatedAt time.Time
+}