diff --git a/cmd/shortener/shortener.go b/cmd/shortener/shortener.go
index aef193f..ec8e072 100644
--- a/cmd/shortener/shortener.go
+++ b/cmd/shortener/shortener.go
@@ -11,10 +11,12 @@ func main() {
 	var serverAddr string
 	var baseURL string
 	var dbFile string
+	var dbCredentials string
 
 	flag.StringVar(&serverAddr, "a", os.Getenv("SERVER_ADDRESS"), "server address")
 	flag.StringVar(&baseURL, "b", os.Getenv("BASE_URL"), "base URL")
 	flag.StringVar(&dbFile, "f", os.Getenv("FILE_STORAGE_PATH"), "file storage path")
+	flag.StringVar(&dbCredentials, "d", os.Getenv("DATABASE_DSN"), "database credentials")
 	flag.Parse()
 
 	if serverAddr == "" {
@@ -25,7 +27,7 @@ func main() {
 		baseURL = "http://" + serverAddr
 	}
 
-	err := app.Start(serverAddr, baseURL, dbFile)
+	err := app.Start(serverAddr, baseURL, dbFile, dbCredentials)
 	if err != nil {
 		panic(err)
 	}
diff --git a/go.mod b/go.mod
index 45105cc..d3565e9 100644
--- a/go.mod
+++ b/go.mod
@@ -15,8 +15,11 @@ require (
 )
 
 require (
+	github.com/google/uuid v1.3.0
+	github.com/jmoiron/sqlx v1.3.5
 	github.com/labstack/echo v3.3.10+incompatible
 	github.com/labstack/gommon v0.3.1 // indirect
+	github.com/lib/pq v1.10.7
 	github.com/mattn/go-colorable v0.1.11 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
diff --git a/go.sum b/go.sum
index c855a40..c3b428e 100644
--- a/go.sum
+++ b/go.sum
@@ -16,11 +16,16 @@ github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY=
 github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/jessevdk/go-flags v0.0.0-20141203071132-1679536dcc89/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
+github.com/jmoiron/sqlx v1.3.5 h1:vFFPA71p1o5gAeqtEAwLU4dnX2napprKtHr7PYIcN3g=
+github.com/jmoiron/sqlx v1.3.5/go.mod h1:nRVWtLre0KfCLJvgxzCsLVMogSvQ1zNJtpYr2Ccp0mQ=
 github.com/jrick/logrotate v1.0.0/go.mod h1:LNinyqDIJnpAur+b8yyulnQw/wDuN1+BYKlTRt3OuAQ=
 github.com/kkdai/bstream v0.0.0-20161212061736-f391b8402d23/go.mod h1:J+Gs4SYgM6CZQHDETBtE9HaSEkGmuNXF86RwHhHUvq4=
 github.com/labstack/echo v3.3.10+incompatible h1:pGRcYk231ExFAyoAjAfD85kQzRJCRI8bbnE7CX5OEgg=
@@ -29,10 +34,14 @@ github.com/labstack/echo/v4 v4.8.0 h1:wdc6yKVaHxkNOEdz4cRZs1pQkwSXPiRjq69yWP4QQS
 github.com/labstack/echo/v4 v4.8.0/go.mod h1:xkCDAdFCIf8jsFQ5NnbK7oqaF/yU1A1X20Ltm0OvSks=
 github.com/labstack/gommon v0.3.1 h1:OomWaJXm7xR6L1HmEtGyQf26TEn7V6X88mktX9kee9o=
 github.com/labstack/gommon v0.3.1/go.mod h1:uW6kP17uPlLJsD3ijUYn3/M5bAxtlZhMI6m3MFxTMTM=
+github.com/lib/pq v1.2.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
+github.com/lib/pq v1.10.7 h1:p7ZhMD+KsSRozJr34udlUrhboJwWAgCg34+/ZZNvZZw=
+github.com/lib/pq v1.10.7/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/mattn/go-colorable v0.1.11 h1:nQ+aFkoE2TMGc0b68U2OKSexC+eq46+XwZzWXHRmPYs=
 github.com/mattn/go-colorable v0.1.11/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
 github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
 github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
+github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/ginkgo v1.7.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
diff --git a/internal/app/app.go b/internal/app/app.go
index 65e5d2c..6c07448 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -9,8 +9,8 @@ import (
 	"github.com/labstack/echo/v4/middleware"
 )
 
-func Start(serverAddr, baseURL, dbFile string) error {
-	h, err := handler.New(serverAddr, baseURL, dbFile)
+func Start(serverAddr, baseURL, dbFile, dbCredentials string) error {
+	h, err := handler.New(serverAddr, baseURL, dbFile, dbCredentials)
 	if err != nil {
 		return fmt.Errorf("handler: %v", err)
 	}
@@ -22,6 +22,9 @@ func Start(serverAddr, baseURL, dbFile string) error {
 	e.POST("/", h.CreateURL)
 	e.GET("/:id", h.RetrieveURL)
 	e.POST("/api/shorten", h.CreateURLInJSON)
+	e.POST("/api/shorten/batch", h.CreateBatchURL)
+	e.GET("/api/user/urls", h.ListURL)
+	e.GET("/ping", h.Ping)
 
 	e.Logger.Fatal(e.Start(serverAddr))
 
diff --git a/internal/handler/handler.go b/internal/handler/handler.go
index b76106b..7326128 100644
--- a/internal/handler/handler.go
+++ b/internal/handler/handler.go
@@ -2,6 +2,9 @@ package handler
 
 import (
 	"crypto"
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -12,24 +15,29 @@ import (
 	"github.com/combodga/Project/internal/storage"
 
 	"github.com/btcsuite/btcutil/base58"
+	"github.com/google/uuid"
 	"github.com/labstack/echo/v4"
 )
 
 type Handler struct {
-	ServerAddr string
-	BaseURL    string
-	Storage    *storage.Storage
+	ServerAddr    string
+	BaseURL       string
+	Storage       *storage.Storage
+	DBCredentials string
+	Key           string
 }
 
-func New(serverAddr, baseURL, dbFile string) (*Handler, error) {
-	s, err := storage.New(dbFile)
+func New(serverAddr, baseURL, dbFile, dbCredentials string) (*Handler, error) {
+	s, err := storage.New(dbFile, dbCredentials)
 	if err != nil {
 		err = fmt.Errorf("storage: %v", err)
 	}
 	return &Handler{
-		ServerAddr: serverAddr,
-		BaseURL:    baseURL,
-		Storage:    s,
+		ServerAddr:    serverAddr,
+		BaseURL:       baseURL,
+		Storage:       s,
+		DBCredentials: dbCredentials,
+		Key:           "b8ffa0f4-3f11-44b1-b0bf-9109f47e468b",
 	}, err
 }
 
@@ -38,6 +46,7 @@ type Link struct {
 }
 
 func (h *Handler) CreateURL(c echo.Context) error {
+	user := getUser(c, h.Key)
 	body, err := io.ReadAll(c.Request().Body)
 	if err != nil {
 		return err
@@ -45,7 +54,7 @@ func (h *Handler) CreateURL(c echo.Context) error {
 
 	link := string(body)
 
-	id, err := h.fetchID(c, link)
+	id, err := h.fetchID(c, user, link)
 	if err != nil {
 		return fmt.Errorf("fetch id: %v", err)
 	}
@@ -54,6 +63,7 @@ func (h *Handler) CreateURL(c echo.Context) error {
 }
 
 func (h *Handler) CreateURLInJSON(c echo.Context) error {
+	user := getUser(c, h.Key)
 	body, err := io.ReadAll(c.Request().Body)
 	if err != nil {
 		return err
@@ -70,7 +80,7 @@ func (h *Handler) CreateURLInJSON(c echo.Context) error {
 		return errors.New("error reading json")
 	}
 
-	id, err := h.fetchID(c, link)
+	id, err := h.fetchID(c, user, link)
 	if err != nil {
 		return fmt.Errorf("fetchID: %v", err)
 	}
@@ -81,6 +91,47 @@ func (h *Handler) CreateURLInJSON(c echo.Context) error {
 	return c.JSON(http.StatusCreated, l)
 }
 
+type LinkJSON struct {
+	CorrelationID string `json:"correlation_id"`
+	OriginalURL   string `json:"original_url"`
+}
+
+type BatchLink struct {
+	CorrelationID string `json:"correlation_id"`
+	ShortURL      string `json:"short_url"`
+}
+
+func (h *Handler) CreateBatchURL(c echo.Context) error {
+	user := getUser(c, h.Key)
+	body, err := io.ReadAll(c.Request().Body)
+	if err != nil {
+		return err
+	}
+
+	var l []LinkJSON
+	err = json.Unmarshal(body, &l)
+	if err != nil {
+		return err
+	}
+
+	var bl []BatchLink
+	for result := range l {
+		link := l[result]
+
+		id, err := h.fetchID(c, user, link.OriginalURL)
+		if err != nil {
+			return fmt.Errorf("fetchID: %v", err)
+		}
+
+		bl = append(bl, BatchLink{
+			CorrelationID: link.CorrelationID,
+			ShortURL:      h.BaseURL + "/" + id,
+		})
+	}
+
+	return c.JSON(http.StatusCreated, bl)
+}
+
 func (h *Handler) RetrieveURL(c echo.Context) error {
 	id := c.Param("id")
 
@@ -92,7 +143,39 @@ func (h *Handler) RetrieveURL(c echo.Context) error {
 	return c.Redirect(http.StatusTemporaryRedirect, url)
 }
 
-func (h *Handler) fetchID(c echo.Context, link string) (string, error) {
+type Element struct {
+	ShortURL    string `json:"short_url"`
+	OriginalURL string `json:"original_url"`
+}
+
+func (h *Handler) ListURL(c echo.Context) error {
+	user := getUser(c, h.Key)
+	list, ok := h.Storage.ListURL(user)
+	if !ok {
+		return c.String(http.StatusNoContent, "error, you haven't any saved links")
+	}
+
+	var arr []*Element
+	for shortURL, originalURL := range list {
+		arr = append(arr, &Element{
+			ShortURL:    h.BaseURL + "/" + shortURL,
+			OriginalURL: originalURL,
+		})
+	}
+
+	return c.JSON(http.StatusOK, arr)
+}
+
+func (h *Handler) Ping(c echo.Context) error {
+	ok := h.Storage.Ping()
+	if !ok {
+		return c.String(http.StatusInternalServerError, "error, no connection to db")
+	}
+
+	return c.String(http.StatusOK, "db connected")
+}
+
+func (h *Handler) fetchID(c echo.Context, user, link string) (string, error) {
 	if len(link) > 2048 {
 		return "", c.String(http.StatusBadRequest, "error, the link cannot be longer than 2048 characters")
 	}
@@ -110,7 +193,7 @@ func (h *Handler) fetchID(c echo.Context, link string) (string, error) {
 		}
 	}
 
-	err = h.Storage.SetURL(id, link)
+	err = h.Storage.SetURL(user, id, link)
 	if err != nil {
 		return "", c.String(http.StatusInternalServerError, "error, failed to store a shortened URL")
 	}
@@ -130,3 +213,43 @@ func shortener(s string) (string, error) {
 
 	return id, nil
 }
+
+func getUser(c echo.Context, key string) string {
+	user, err1 := readCookie(c, "user")
+	sign, err2 := readCookie(c, "sign")
+	if err1 == nil && err2 == nil && sign == getSign(user, key) {
+		return user
+	}
+
+	user = randUser()
+	writeCookie(c, "user", user)
+	writeCookie(c, "sign", getSign(user, key))
+	return user
+}
+
+func randUser() string {
+	uuidWithHyphen := uuid.New()
+	return uuidWithHyphen.String()
+}
+
+func getSign(user, key string) string {
+	h := hmac.New(sha256.New, []byte(key))
+	h.Write([]byte(user))
+	dst := h.Sum(nil)
+	return hex.EncodeToString(dst)[:32]
+}
+
+func writeCookie(c echo.Context, name, value string) {
+	cookie := new(http.Cookie)
+	cookie.Name = name
+	cookie.Value = value
+	c.SetCookie(cookie)
+}
+
+func readCookie(c echo.Context, name string) (string, error) {
+	cookie, err := c.Cookie(name)
+	if err != nil {
+		return "", err
+	}
+	return cookie.Value, nil
+}
diff --git a/internal/handler/handler_test.go b/internal/handler/handler_test.go
index c889d06..284b84c 100644
--- a/internal/handler/handler_test.go
+++ b/internal/handler/handler_test.go
@@ -27,7 +27,7 @@ var (
 
 func TestInit(t *testing.T) {
 	var err error
-	H, err = New("localhost:8080", "http://localhost:8080", "")
+	H, err = New("localhost:8080", "http://localhost:8080", "", "")
 	if err != nil {
 		t.Fatal("can't start test")
 	}
diff --git a/internal/storage/storage.go b/internal/storage/storage.go
index 8974201..065ec5a 100644
--- a/internal/storage/storage.go
+++ b/internal/storage/storage.go
@@ -1,43 +1,91 @@
 package storage
 
 import (
+	"database/sql"
 	"encoding/json"
 	"errors"
 	"os"
 	"sync"
+
+	"github.com/jmoiron/sqlx"
+	_ "github.com/lib/pq"
 )
 
 type Storage struct {
-	DBFile string
-	Pairs  map[string]string
-	Mutex  *sync.RWMutex
+	DBFile        string
+	DBCredentials string
+	Pairs         map[string]map[string]string
+	Mutex         *sync.RWMutex
 }
 
-func New(dbFile string) (*Storage, error) {
-	s := &Storage{
-		DBFile: dbFile,
-		Pairs:  make(map[string]string),
-		Mutex:  &sync.RWMutex{},
-	}
+type Link struct {
+	User string `db:"usr"`
+	ID   string `db:"short"`
+	Link string `db:"long"`
+}
 
-	if dbFile == "" {
-		return s, nil
+func New(dbFile, dbCredentials string) (*Storage, error) {
+	s := &Storage{
+		DBFile:        dbFile,
+		DBCredentials: dbCredentials,
+		Pairs:         make(map[string]map[string]string),
+		Mutex:         &sync.RWMutex{},
 	}
 
 	s.Mutex.Lock()
 	defer s.Mutex.Unlock()
 
-	pairsStr, err := os.ReadFile(dbFile)
-	if errors.Is(err, os.ErrNotExist) {
+	if dbCredentials != "" {
+		db, err := sqlx.Connect("postgres", s.DBCredentials)
+		if err != nil {
+			return s, err
+		}
+		defer db.Close()
+
+		db.MustExec(`
+			CREATE TABLE IF NOT EXISTS shortener (
+				usr text,
+				short text,
+				long text
+			);
+		`)
+
+		link := Link{}
+		rows, err := db.Queryx("SELECT * FROM shortener")
+		if err != nil {
+			return s, err
+		}
+		for rows.Next() {
+			err := rows.StructScan(&link)
+			if err != nil {
+				return s, err
+			}
+			if len(s.Pairs[link.User]) == 0 {
+				s.Pairs[link.User] = make(map[string]string)
+			}
+			s.Pairs[link.User][link.ID] = link.Link
+		}
+		err = rows.Err()
+		if err != nil {
+			return s, err
+		}
+
 		return s, nil
 	}
-	if err != nil {
-		return s, err
-	}
 
-	err = json.Unmarshal(pairsStr, &s.Pairs)
-	if err != nil {
-		return s, err
+	if dbFile != "" {
+		pairsStr, err := os.ReadFile(dbFile)
+		if errors.Is(err, os.ErrNotExist) {
+			return s, nil
+		}
+		if err != nil {
+			return s, err
+		}
+
+		err = json.Unmarshal(pairsStr, &s.Pairs)
+		if err != nil {
+			return s, err
+		}
 	}
 
 	return s, nil
@@ -49,34 +97,70 @@ func (s *Storage) GetURL(id string) (string, bool) {
 	}
 
 	s.Mutex.Lock()
-	url, ok := s.Pairs[id]
-	s.Mutex.Unlock()
-	if !ok {
-		return "", false
+	defer s.Mutex.Unlock()
+
+	for user := range s.Pairs {
+		url, ok := s.Pairs[user][id]
+		if ok {
+			return url, true
+		}
 	}
 
-	return url, true
+	return "", false
 }
 
-func (s *Storage) SetURL(id, link string) error {
+func (s *Storage) SetURL(user, id, link string) error {
 	s.Mutex.Lock()
 	defer s.Mutex.Unlock()
 
-	s.Pairs[id] = link
+	if len(s.Pairs[user]) == 0 {
+		s.Pairs[user] = make(map[string]string)
+	}
+	s.Pairs[user][id] = link
+
+	if s.DBCredentials != "" {
+		db, err := sqlx.Connect("postgres", s.DBCredentials)
+		if err != nil {
+			return err
+		}
+		defer db.Close()
+
+		db.MustExec("INSERT INTO shortener VALUES ($1, $2, $3)", user, id, link)
 
-	if s.DBFile == "" {
 		return nil
 	}
 
-	jsonStr, err := json.Marshal(s.Pairs)
-	if err != nil {
-		return err
-	}
+	if s.DBFile != "" {
+		jsonStr, err := json.Marshal(s.Pairs)
+		if err != nil {
+			return err
+		}
 
-	err = os.WriteFile(s.DBFile, []byte(jsonStr), 0777)
-	if err != nil {
-		return err
+		err = os.WriteFile(s.DBFile, []byte(jsonStr), 0777)
+		if err != nil {
+			return err
+		}
 	}
 
 	return nil
 }
+
+func (s *Storage) ListURL(user string) (map[string]string, bool) {
+	s.Mutex.Lock()
+	list, ok := s.Pairs[user]
+	s.Mutex.Unlock()
+	if !ok {
+		return list, false
+	}
+
+	return list, true
+}
+
+func (s *Storage) Ping() bool {
+	db, err := sql.Open("postgres", s.DBCredentials)
+	if err != nil {
+		return false
+	}
+	db.Close()
+	return true
+}
diff --git a/internal/storage/storage_test.go b/internal/storage/storage_test.go
index d26a5e2..b71d3f2 100644
--- a/internal/storage/storage_test.go
+++ b/internal/storage/storage_test.go
@@ -6,18 +6,19 @@ import (
 
 var (
 	tests = []struct {
+		user  string
 		key   string
 		value string
 	}{
-		{key: "key", value: "value"},
-		{key: "a", value: "b"},
+		{user: "test", key: "key", value: "value"},
+		{user: "test", key: "a", value: "b"},
 	}
 	S *Storage
 )
 
 func TestInit(t *testing.T) {
 	var err error
-	S, err = New("")
+	S, err = New("", "")
 	if err != nil {
 		t.Fatal("can't start test")
 	}
@@ -25,7 +26,7 @@ func TestInit(t *testing.T) {
 
 func TestSetURL(t *testing.T) {
 	for _, testCase := range tests {
-		err := S.SetURL(testCase.key, testCase.value)
+		err := S.SetURL(testCase.user, testCase.key, testCase.value)
 		if err != nil {
 			t.Fatalf("can't save value %v for key %v", testCase.value, testCase.key)
 		}