diff --git a/dataprovider/bolt.go b/dataprovider/bolt.go
index 0821ffef..5d071956 100644
--- a/dataprovider/bolt.go
+++ b/dataprovider/bolt.go
@@ -161,7 +161,7 @@ func (p BoltProvider) userExists(username string) (User, error) {
 		}
 		u := bucket.Get([]byte(username))
 		if u == nil {
-			return &RecordNotFoundError{err: fmt.Sprintf("username %v does not exist", user.Username)}
+			return &RecordNotFoundError{err: fmt.Sprintf("username %v does not exist", username)}
 		}
 		return json.Unmarshal(u, &user)
 	})
@@ -242,6 +242,9 @@ func (p BoltProvider) deleteUser(user User) error {
 func (p BoltProvider) getUsers(limit int, offset int, order string, username string) ([]User, error) {
 	users := []User{}
 	var err error
+	if limit <= 0 {
+		return users, err
+	}
 	if len(username) > 0 {
 		if offset == 0 {
 			user, err := p.userExists(username)
@@ -252,9 +255,6 @@ func (p BoltProvider) getUsers(limit int, offset int, order string, username str
 		return users, err
 	}
 	err = p.dbHandle.View(func(tx *bolt.Tx) error {
-		if limit <= 0 {
-			return nil
-		}
 		bucket, _, err := getBuckets(tx)
 		if err != nil {
 			return err
diff --git a/dataprovider/dataprovider.go b/dataprovider/dataprovider.go
index afc07457..b038a4b7 100644
--- a/dataprovider/dataprovider.go
+++ b/dataprovider/dataprovider.go
@@ -37,6 +37,8 @@ const (
 	MySQLDataProviderName = "mysql"
 	// BoltDataProviderName name for bbolt key/value store provider
 	BoltDataProviderName = "bolt"
+	// MemoryDataProviderName name for memory provider
+	MemoryDataProviderName = "memory"
 
 	argonPwdPrefix           = "$argon2id$"
 	bcryptPwdPrefix          = "$2a$"
@@ -50,7 +52,8 @@ const (
 
 var (
 	// SupportedProviders data provider configured in the sftpgo.conf file must match of these strings
-	SupportedProviders = []string{SQLiteDataProviderName, PGSQLDataProviderName, MySQLDataProviderName, BoltDataProviderName}
+	SupportedProviders = []string{SQLiteDataProviderName, PGSQLDataProviderName, MySQLDataProviderName,
+		BoltDataProviderName, MemoryDataProviderName}
 	// ValidPerms list that contains all the valid permissions for an user
 	ValidPerms = []string{PermAny, PermListItems, PermDownload, PermUpload, PermOverwrite, PermRename, PermDelete,
 		PermCreateDirs, PermCreateSymlinks}
@@ -179,6 +182,8 @@ func Initialize(cnf Config, basePath string) error {
 		err = initializeMySQLProvider()
 	} else if config.Driver == BoltDataProviderName {
 		err = initializeBoltProvider(basePath)
+	} else if config.Driver == MemoryDataProviderName {
+		err = initializeMemoryProvider()
 	} else {
 		err = fmt.Errorf("unsupported data provider: %v", config.Driver)
 	}
diff --git a/dataprovider/memory.go b/dataprovider/memory.go
new file mode 100644
index 00000000..4c4b7fba
--- /dev/null
+++ b/dataprovider/memory.go
@@ -0,0 +1,279 @@
+package dataprovider
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/drakkan/sftpgo/logger"
+	"github.com/drakkan/sftpgo/utils"
+)
+
+var (
+	errMemoryProviderClosed = errors.New("memory provider is closed")
+)
+
+type memoryProviderHandle struct {
+	isClosed bool
+	// slice with ordered usernames
+	usernames []string
+	// mapping between ID and username
+	usersIdx map[int64]string
+	// map for users, username is the key
+	users map[string]User
+	lock  *sync.Mutex
+}
+
+// MemoryProvider auth provider for a memory store
+type MemoryProvider struct {
+	dbHandle *memoryProviderHandle
+}
+
+func initializeMemoryProvider() error {
+	provider = MemoryProvider{
+		dbHandle: &memoryProviderHandle{
+			isClosed:  false,
+			usernames: []string{},
+			usersIdx:  make(map[int64]string),
+			users:     make(map[string]User),
+			lock:      new(sync.Mutex),
+		},
+	}
+	return nil
+}
+
+func (p MemoryProvider) checkAvailability() error {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return errMemoryProviderClosed
+	}
+	return nil
+}
+
+func (p MemoryProvider) close() error {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return errMemoryProviderClosed
+	}
+	p.dbHandle.isClosed = true
+	return nil
+}
+
+func (p MemoryProvider) validateUserAndPass(username string, password string) (User, error) {
+	var user User
+	if len(password) == 0 {
+		return user, errors.New("Credentials cannot be null or empty")
+	}
+	user, err := p.userExists(username)
+	if err != nil {
+		providerLog(logger.LevelWarn, "error authenticating user: %v, error: %v", username, err)
+		return user, err
+	}
+	return checkUserAndPass(user, password)
+}
+
+func (p MemoryProvider) validateUserAndPubKey(username string, pubKey string) (User, string, error) {
+	var user User
+	if len(pubKey) == 0 {
+		return user, "", errors.New("Credentials cannot be null or empty")
+	}
+	user, err := p.userExists(username)
+	if err != nil {
+		providerLog(logger.LevelWarn, "error authenticating user: %v, error: %v", username, err)
+		return user, "", err
+	}
+	return checkUserAndPubKey(user, pubKey)
+}
+
+func (p MemoryProvider) getUserByID(ID int64) (User, error) {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return User{}, errMemoryProviderClosed
+	}
+	if val, ok := p.dbHandle.usersIdx[ID]; ok {
+		return p.userExistsInternal(val)
+	}
+	return User{}, &RecordNotFoundError{err: fmt.Sprintf("user with ID %v does not exist", ID)}
+}
+
+func (p MemoryProvider) updateQuota(username string, filesAdd int, sizeAdd int64, reset bool) error {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return errMemoryProviderClosed
+	}
+	user, err := p.userExistsInternal(username)
+	if err != nil {
+		providerLog(logger.LevelWarn, "unable to update quota for user %v error: %v", username, err)
+		return err
+	}
+	if reset {
+		user.UsedQuotaSize = sizeAdd
+		user.UsedQuotaFiles = filesAdd
+	} else {
+		user.UsedQuotaSize += sizeAdd
+		user.UsedQuotaFiles += filesAdd
+	}
+	user.LastQuotaUpdate = utils.GetTimeAsMsSinceEpoch(time.Now())
+	p.dbHandle.users[user.Username] = user
+	return nil
+}
+
+func (p MemoryProvider) getUsedQuota(username string) (int, int64, error) {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return 0, 0, errMemoryProviderClosed
+	}
+	user, err := p.userExistsInternal(username)
+	if err != nil {
+		providerLog(logger.LevelWarn, "unable to get quota for user %v error: %v", username, err)
+		return 0, 0, err
+	}
+	return user.UsedQuotaFiles, user.UsedQuotaSize, err
+}
+
+func (p MemoryProvider) addUser(user User) error {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return errMemoryProviderClosed
+	}
+	err := validateUser(&user)
+	if err != nil {
+		return err
+	}
+	_, err = p.userExistsInternal(user.Username)
+	if err == nil {
+		return fmt.Errorf("username %v already exists", user.Username)
+	}
+	user.ID = p.getNextID()
+	p.dbHandle.users[user.Username] = user
+	p.dbHandle.usersIdx[user.ID] = user.Username
+	p.dbHandle.usernames = append(p.dbHandle.usernames, user.Username)
+	sort.Strings(p.dbHandle.usernames)
+	return nil
+}
+
+func (p MemoryProvider) updateUser(user User) error {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return errMemoryProviderClosed
+	}
+	err := validateUser(&user)
+	if err != nil {
+		return err
+	}
+	_, err = p.userExistsInternal(user.Username)
+	if err != nil {
+		return err
+	}
+	p.dbHandle.users[user.Username] = user
+	return nil
+}
+
+func (p MemoryProvider) deleteUser(user User) error {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return errMemoryProviderClosed
+	}
+	_, err := p.userExistsInternal(user.Username)
+	if err != nil {
+		return err
+	}
+	delete(p.dbHandle.users, user.Username)
+	delete(p.dbHandle.usersIdx, user.ID)
+	// this could be more efficient
+	p.dbHandle.usernames = []string{}
+	for username := range p.dbHandle.users {
+		p.dbHandle.usernames = append(p.dbHandle.usernames, username)
+	}
+	sort.Strings(p.dbHandle.usernames)
+	return nil
+}
+
+func (p MemoryProvider) getUsers(limit int, offset int, order string, username string) ([]User, error) {
+	users := []User{}
+	var err error
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return users, errMemoryProviderClosed
+	}
+	if limit <= 0 {
+		return users, err
+	}
+	if len(username) > 0 {
+		if offset == 0 {
+			user, err := p.userExistsInternal(username)
+			if err == nil {
+				user.Password = ""
+				users = append(users, user)
+			}
+		}
+		return users, err
+	}
+	itNum := 0
+	if order == "ASC" {
+		for _, username := range p.dbHandle.usernames {
+			itNum++
+			if itNum <= offset {
+				continue
+			}
+			user := p.dbHandle.users[username]
+			user.Password = ""
+			users = append(users, user)
+			if len(users) >= limit {
+				break
+			}
+		}
+	} else {
+		for i := len(p.dbHandle.usernames) - 1; i >= 0; i-- {
+			itNum++
+			if itNum <= offset {
+				continue
+			}
+			username := p.dbHandle.usernames[i]
+			user := p.dbHandle.users[username]
+			user.Password = ""
+			users = append(users, user)
+			if len(users) >= limit {
+				break
+			}
+		}
+	}
+	return users, err
+}
+
+func (p MemoryProvider) userExists(username string) (User, error) {
+	p.dbHandle.lock.Lock()
+	defer p.dbHandle.lock.Unlock()
+	if p.dbHandle.isClosed {
+		return User{}, errMemoryProviderClosed
+	}
+	return p.userExistsInternal(username)
+}
+
+func (p MemoryProvider) userExistsInternal(username string) (User, error) {
+	if val, ok := p.dbHandle.users[username]; ok {
+		return val.getACopy(), nil
+	}
+	return User{}, &RecordNotFoundError{err: fmt.Sprintf("username %v does not exist", username)}
+}
+
+func (p MemoryProvider) getNextID() int64 {
+	nextID := int64(1)
+	for id := range p.dbHandle.usersIdx {
+		if id >= nextID {
+			nextID = id + 1
+		}
+	}
+	return nextID
+}
diff --git a/dataprovider/user.go b/dataprovider/user.go
index 641d33d9..c86796d3 100644
--- a/dataprovider/user.go
+++ b/dataprovider/user.go
@@ -189,3 +189,28 @@ func (u *User) GetInfoString() string {
 	}
 	return result
 }
+
+func (u *User) getACopy() User {
+	pubKeys := make([]string, len(u.PublicKeys))
+	copy(pubKeys, u.PublicKeys)
+	permissions := make([]string, len(u.Permissions))
+	copy(permissions, u.Permissions)
+	return User{
+		ID:                u.ID,
+		Username:          u.Username,
+		Password:          u.Password,
+		PublicKeys:        pubKeys,
+		HomeDir:           u.HomeDir,
+		UID:               u.UID,
+		GID:               u.GID,
+		MaxSessions:       u.MaxSessions,
+		QuotaSize:         u.QuotaSize,
+		QuotaFiles:        u.QuotaFiles,
+		Permissions:       permissions,
+		UsedQuotaSize:     u.UsedQuotaSize,
+		UsedQuotaFiles:    u.UsedQuotaFiles,
+		LastQuotaUpdate:   u.LastQuotaUpdate,
+		UploadBandwidth:   u.UploadBandwidth,
+		DownloadBandwidth: u.DownloadBandwidth,
+	}
+}
diff --git a/service/service.go b/service/service.go
index 4240d4ca..7a917e9c 100644
--- a/service/service.go
+++ b/service/service.go
@@ -143,11 +143,9 @@ func (s *Service) StartPortableMode(sftpdPort int, enableSCP bool) error {
 	}
 	tempDir := os.TempDir()
 	instanceID := xid.New().String()
-	databasePath := filepath.Join(tempDir, instanceID+".db")
 	s.LogFilePath = filepath.Join(tempDir, instanceID+".log")
 	dataProviderConf := config.GetProviderConf()
-	dataProviderConf.Driver = dataprovider.BoltDataProviderName
-	dataProviderConf.Name = databasePath
+	dataProviderConf.Driver = dataprovider.MemoryDataProviderName
 	config.SetProviderConf(dataProviderConf)
 	httpdConf := config.GetHTTPDConfig()
 	httpdConf.BindPort = 0
diff --git a/sftpd/server.go b/sftpd/server.go
index 6c7bf30f..0c1c73e6 100644
--- a/sftpd/server.go
+++ b/sftpd/server.go
@@ -277,8 +277,7 @@ func (c Configuration) AcceptInboundConnection(conn net.Conn, config *ssh.Server
 						if err := ssh.Unmarshal(req.Payload, &msg); err == nil {
 							name, scpArgs, err := parseCommandPayload(msg.Command)
 							connection.Log(logger.LevelDebug, logSender, "new exec command: %#v args: %v user: %v, error: %v",
-								name, scpArgs,
-								connection.User.Username, err)
+								name, scpArgs, connection.User.Username, err)
 							if err == nil && name == "scp" && len(scpArgs) >= 2 {
 								ok = true
 								connection.protocol = protocolSCP
diff --git a/sftpd/sftpd_test.go b/sftpd/sftpd_test.go
index 11e679ff..6289ad08 100644
--- a/sftpd/sftpd_test.go
+++ b/sftpd/sftpd_test.go
@@ -200,7 +200,7 @@ func TestBasicSFTPHandling(t *testing.T) {
 		testFileSize := int64(65535)
 		expectedQuotaSize := user.UsedQuotaSize + testFileSize
 		expectedQuotaFiles := user.UsedQuotaFiles + 1
-		err = createTestFile(testFilePath, testFileSize)
+		createTestFile(testFilePath, testFileSize)
 		err = sftpUploadFile(testFilePath, path.Join("/missing_dir", testFileName), testFileSize, client)
 		if err == nil {
 			t.Errorf("upload a file to a missing dir must fail")