diff --git a/storage/hybrid/onlydoc.go b/storage/hybrid/onlydoc.go
new file mode 100644
index 0000000..31bf469
--- /dev/null
+++ b/storage/hybrid/onlydoc.go
@@ -0,0 +1,58 @@
+package hybrid
+
+// Provider interace implement lifecycle for one sessions
+type Provider interface {
+	//set additional params for provider ex: sql db connection, filesystem path .. etc.
+	SetParams(params any) error
+	//create new session using sid value 1) in meory 2) into WAL file create new session op.
+	Init(sid string) (Session, error)
+	//read and return existing session by id or if not exist create new session 1) from
+	//memory WAL file no need modify i no call Init from Load...
+	Load(sid string) (Session, error)
+	//destroy remove session with sid from storage if exist 1) in memory 2) in WAL ile
+	//add destroy operation
+	Destroy(sid string) error
+	//regenerate id change old sid to newsid and preserve existing session data 1) in memory
+	//and 2) add change id op. into WAL file
+	ChangeID(oldsid, newsid string) (err error)
+	//Exists return true if session with sid exist
+	Exists(sid string) bool
+	//gc remove all outdated sessions 1) in memory and 2) add every destroy op. into WAL
+	GC(maxlifetime int64)
+}
+
+// Session interface implement storage for one session and have maxLifetime and lastAccessTime
+/*
+Session change WAL file (SCF) file format:
+
+	   | OP. NUM. | SID | DATA (binary stream) | LEN |
+
+		OP. NUM. : uint8
+
+		0 - create new session
+		1 - destroy session
+		2 - change session ID
+		3 - modify (create, update and delete) session key/val data
+
+		SID:
+		   - 32 bit. session ID
+
+		DATA:
+			0: --no data--
+			1: --no-data--
+			2: new SID
+			3:
+				create: key([]byte)|val([]byte)
+				delete: key([]byte)
+				update: key([]byte)|val([]byte)
+*/
+type Session interface {
+	//set session value and update last access time 1) in memory and 2) add Set key op. into WAL
+	Set(key, value any) error
+	//get session value and update last access time 1) from memory and no need any WAL modiication
+	Get(key any) (v any, err error)
+	//delete session value 1) in memory and 2) add delete key op. into WAL
+	Delete(key any) error
+	//get session id 1) from memory and no need mod. WAL
+	SessionID() string
+}
diff --git a/storage/hybrid/scf/scf.go b/storage/hybrid/scf/scf.go
new file mode 100644
index 0000000..fbb820d
--- /dev/null
+++ b/storage/hybrid/scf/scf.go
@@ -0,0 +1,20 @@
+// Package scf provide Session Changes Log file
+package scf
+
+import (
+	"fmt"
+	"os"
+)
+
+type Scf struct {
+	fd *os.File
+}
+
+// NewScf open or create if not exists Session Changes Log file
+func NewScf(fpath string) (scf *Scf, err error) {
+	var fd *os.File
+	if fd, err = os.Create(fpath); err != nil {
+		return nil, fmt.Errorf("can not open(create) SCF file: %s err: %v", fpath, err)
+	}
+	return &Scf{fd}, nil
+}