diff --git a/database/database.go b/database/database.go
index 41fb32e..364e1ae 100644
--- a/database/database.go
+++ b/database/database.go
@@ -148,7 +148,15 @@ func NewAccount(database *sql.DB, account Account) error {
 }
 
 func UpdateAccount(database *sql.DB, account Account) error {
-	_, err := database.Exec("UPDATE accounts SET name = $1, kind = $2 WHERE id = $3", account.Name, account.Kind, account.ID)
+	exists, err := existAccount(database, int(account.ID))
+	if err != nil {
+		return err
+	}
+	if !exists {
+		return errors.New("account does not exist")
+	}
+
+	_, err = database.Exec("UPDATE accounts SET name = $1, kind = $2 WHERE id = $3", account.Name, account.Kind, account.ID)
 	if err != nil {
 		return err
 	}
@@ -157,7 +165,15 @@ func UpdateAccount(database *sql.DB, account Account) error {
 }
 
 func DeleteAccount(database *sql.DB, id int) error {
-	_, err := database.Exec("DELETE FROM accounts WHERE id = $1", id)
+	exists, err := existAccount(database, id)
+	if err != nil {
+		return err
+	}
+	if !exists {
+		return errors.New("account does not exist")
+	}
+
+	_, err = database.Exec("DELETE FROM accounts WHERE id = $1", id)
 	if err != nil {
 		return err
 	}
@@ -175,6 +191,18 @@ func GetAccount(database *sql.DB, id int) (Account, error) {
 
 }
 
+func existTransaction(database *sql.DB, id int) (bool, error) {
+	err := database.QueryRow("SELECT id FROM transactions WHERE id = $1", id).Scan(&id)
+	if err != nil {
+		if err != sql.ErrNoRows {
+			return false, err
+		}
+		return false, nil
+	}
+	return true, nil
+
+}
+
 func NewTransaction(database *sql.DB, transaction Transaction) error {
 	_, err := database.Exec("INSERT INTO transactions (amount, debit, offset_account, account, time, description) VALUES ($1, $2, $3, $4, $5, $6)", transaction.Amount, transaction.Debit, transaction.OffsetAccount, transaction.Account, transaction.Date, transaction.Description)
 	if err != nil {
@@ -185,7 +213,15 @@ func NewTransaction(database *sql.DB, transaction Transaction) error {
 }
 
 func UpdateTransaction(database *sql.DB, transaction Transaction) error {
-	_, err := database.Exec("UPDATE transactions SET amount = $1, debit = $2, offset_account = $3, account = $4, time = $5, description = $6 WHERE id = $7", transaction.Amount, transaction.Debit, transaction.OffsetAccount, transaction.Account, transaction.Date, transaction.Description, transaction.ID)
+	exists, err := existTransaction(database, int(transaction.ID))
+	if err != nil {
+		return err
+	}
+
+	if !exists {
+		return errors.New("transaction already exists")
+	}
+	_, err = database.Exec("UPDATE transactions SET amount = $1, debit = $2, offset_account = $3, account = $4, time = $5, description = $6 WHERE id = $7", transaction.Amount, transaction.Debit, transaction.OffsetAccount, transaction.Account, transaction.Date, transaction.Description, transaction.ID)
 	if err != nil {
 		return err
 	}
@@ -194,7 +230,15 @@ func UpdateTransaction(database *sql.DB, transaction Transaction) error {
 }
 
 func DeleteTransaction(database *sql.DB, id int) error {
-	_, err := database.Exec("DELETE FROM transactions WHERE id = $1", id)
+	exists, err := existTransaction(database, id)
+	if err != nil {
+		return err
+	}
+
+	if !exists {
+		return errors.New("transaction already exists")
+	}
+	_, err = database.Exec("DELETE FROM transactions WHERE id = $1", id)
 	if err != nil {
 		return err
 	}
diff --git a/server/account.go b/server/account.go
index c71d8ce..73c472c 100644
--- a/server/account.go
+++ b/server/account.go
@@ -1,31 +1,143 @@
 package server
 
 import (
+	"encoding/json"
 	"net/http"
+	"strconv"
 
+	"github.com/LeRoid-hub/Bookholder-API/database"
 	"github.com/gin-gonic/gin"
 )
 
 func getAccount(c *gin.Context) {
+	id := c.Param("AccountID")
+
+	idInt, err := strconv.Atoi(id)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be an integer",
+		})
+		return
+	}
+
+	if idInt < 1 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be greater than 0",
+		})
+		return
+	}
+
+	acc, err := database.GetAccount(Database, idInt)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
+	if acc.ID == 0 {
+		c.JSON(http.StatusNotFound, gin.H{
+			"message": "account not found",
+		})
+		return
+	}
+
+	jsondata, err := json.Marshal(acc)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
 	c.JSON(http.StatusOK, gin.H{
-		"message": "getAccount",
+		"account": jsondata,
 	})
 }
 
 func newAccount(c *gin.Context) {
-	c.JSON(http.StatusOK, gin.H{
-		"message": "newAccount",
+	var acc database.Account
+	err := c.BindJSON(&acc)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid json",
+		})
+		return
+	}
+
+	err = database.NewAccount(Database, acc)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
+	c.JSON(http.StatusCreated, gin.H{
+		"message": "account created",
 	})
 }
 
 func updateAccount(c *gin.Context) {
+	var acc database.Account
+	err := c.BindJSON(&acc)
+
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid json",
+		})
+		return
+	}
+
+	acc.ID = uint(acc.ID)
+
+	if acc.ID < 1 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be greater than 0",
+		})
+		return
+	}
+
+	err = database.UpdateAccount(Database, acc)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
 	c.JSON(http.StatusOK, gin.H{
-		"message": "updateAccount",
+		"message": "account updated",
 	})
 }
 
 func deleteAccount(c *gin.Context) {
+	id := c.Param("AccountID")
+
+	idInt, err := strconv.Atoi(id)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be an integer",
+		})
+		return
+	}
+
+	if idInt < 1 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be greater than 0",
+		})
+		return
+	}
+
+	err = database.DeleteAccount(Database, idInt)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
 	c.JSON(http.StatusOK, gin.H{
-		"message": "deleteAccount",
+		"message": "account deleted",
 	})
 }
diff --git a/server/server.go b/server/server.go
index ce387f0..1fc9d09 100644
--- a/server/server.go
+++ b/server/server.go
@@ -41,6 +41,7 @@ func Run(env map[string]string, db *database.DB) {
 
 	r := gin.Default()
 
+	// Index
 	r.GET("/", welcome)
 
 	v1 := r.Group("/v1")
@@ -51,7 +52,7 @@ func Run(env map[string]string, db *database.DB) {
 		//Account
 		v1.GET("/Account/:AccountID", checkAuth, getAccount)
 		v1.POST("/NewAccount", checkAuth, newAccount)
-		v1.PUT("/UpdateAccount/:AccountID", checkAuth, updateAccount)
+		v1.PUT("/UpdateAccount", checkAuth, updateAccount)
 		v1.DELETE("/DeleteAccount/:AccountID", checkAuth, deleteAccount)
 
 		//Transaction
diff --git a/server/transaction.go b/server/transaction.go
index b8eaa3b..fad7511 100644
--- a/server/transaction.go
+++ b/server/transaction.go
@@ -1,14 +1,57 @@
 package server
 
 import (
+	"encoding/json"
 	"net/http"
+	"strconv"
 
+	"github.com/LeRoid-hub/Bookholder-API/database"
 	"github.com/gin-gonic/gin"
 )
 
 func getTransaction(c *gin.Context) {
+	id := c.Param("TransactionID")
+
+	idInt, err := strconv.Atoi(id)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be an integer",
+		})
+		return
+	}
+
+	if idInt < 1 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be greater than 0",
+		})
+		return
+	}
+
+	transaction, err := database.GetTransaction(Database, idInt)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
+	if transaction.ID == 0 {
+		c.JSON(http.StatusNotFound, gin.H{
+			"message": "transaction not found",
+		})
+		return
+	}
+
+	jasondata, err := json.Marshal(transaction)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
 	c.JSON(http.StatusOK, gin.H{
-		"message": "getTransaction",
+		"transaction": jasondata,
 	})
 }
 
@@ -16,26 +59,160 @@ func getTransactions(c *gin.Context) {
 	year := c.Param("year")
 	month := c.Param("month")
 
-	message := "getTransactions " + year + " " + month
+	yearInt, err := strconv.Atoi(year)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid year; must be an integer",
+		})
+		return
+	}
+
+	if yearInt < 1 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid year; must be greater than 0",
+		})
+		return
+	}
+
+	monthInt, err := strconv.Atoi(month)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid month; must be an integer",
+		})
+		return
+	}
+
+	if monthInt < 1 || monthInt > 12 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid month; must be between 1 and 12",
+		})
+		return
+	}
+
+	account := c.Param("AccountID")
+	accountInt, err := strconv.Atoi(account)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid account; must be an integer",
+		})
+		return
+	}
+
+	if accountInt < 1 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid account; must be greater than 0",
+		})
+		return
+	}
+
+	transactions, err := database.GetTransactions(Database, accountInt, yearInt, monthInt)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
+	jasondata, err := json.Marshal(transactions)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
 	c.JSON(http.StatusOK, gin.H{
-		"message": message,
+		"transactions": jasondata,
 	})
 }
 
 func newTransaction(c *gin.Context) {
-	c.JSON(http.StatusOK, gin.H{
-		"message": "newTransaction",
+	var transaction database.Transaction
+	err := c.BindJSON(&transaction)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid json",
+		})
+		return
+	}
+
+	if transaction.OffsetAccount == transaction.Account {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid offset account; must be different from account",
+		})
+		return
+	}
+
+	err = database.NewTransaction(Database, transaction)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error: " + err.Error(),
+		})
+		return
+	}
+
+	c.JSON(http.StatusCreated, gin.H{
+		"message": "transaction created",
 	})
 }
 
 func updateTransaction(c *gin.Context) {
+	var transaction database.Transaction
+	err := c.BindJSON(&transaction)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid json",
+		})
+		return
+	}
+
+	if transaction.OffsetAccount == transaction.Account {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid offset account; must be different from account",
+		})
+		return
+	}
+
+	err = database.UpdateTransaction(Database, transaction)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
 	c.JSON(http.StatusOK, gin.H{
-		"message": "updateTransaction",
+		"message": "transaction updated",
 	})
 }
 
 func deleteTransaction(c *gin.Context) {
+	id := c.Param("TransactionID")
+
+	idInt, err := strconv.Atoi(id)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be an integer",
+		})
+		return
+	}
+
+	if idInt < 1 {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"message": "invalid id; must be greater than 0",
+		})
+		return
+	}
+
+	err = database.DeleteTransaction(Database, idInt)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{
+			"message": "internal server error",
+		})
+		return
+	}
+
 	c.JSON(http.StatusOK, gin.H{
-		"message": "deleteTransaction",
+		"message": "transaction deleted",
 	})
 }