diff --git a/api/handler/api.go b/api/handler/api.go
index 2d9e01d..2b35527 100644
--- a/api/handler/api.go
+++ b/api/handler/api.go
@@ -20,7 +20,7 @@ import (
 type (
 	handler struct {
 		log       *zap.Logger
-		obj       layer.Client
+		obj       *layer.Layer
 		cfg       Config
 		ape       APE
 		frostfsid FrostFSID
@@ -68,7 +68,7 @@ const (
 var _ api.Handler = (*handler)(nil)
 
 // New creates new api.Handler using given logger and client.
-func New(log *zap.Logger, obj layer.Client, cfg Config, storage APE, ffsid FrostFSID) (api.Handler, error) {
+func New(log *zap.Logger, obj *layer.Layer, cfg Config, storage APE, ffsid FrostFSID) (api.Handler, error) {
 	switch {
 	case obj == nil:
 		return nil, errors.New("empty FrostFS Object Layer")
diff --git a/api/handler/handlers_test.go b/api/handler/handlers_test.go
index 7a1b6c4..5280c0f 100644
--- a/api/handler/handlers_test.go
+++ b/api/handler/handlers_test.go
@@ -58,7 +58,7 @@ func (hc *handlerContext) MockedPool() *layer.TestFrostFS {
 	return hc.tp
 }
 
-func (hc *handlerContext) Layer() layer.Client {
+func (hc *handlerContext) Layer() *layer.Layer {
 	return hc.h.obj
 }
 
diff --git a/api/layer/compound.go b/api/layer/compound.go
index d4560d3..7ff3e37 100644
--- a/api/layer/compound.go
+++ b/api/layer/compound.go
@@ -9,7 +9,7 @@ import (
 	s3errors "git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/errors"
 )
 
-func (n *layer) GetObjectTaggingAndLock(ctx context.Context, objVersion *data.ObjectVersion, nodeVersion *data.NodeVersion) (map[string]string, data.LockInfo, error) {
+func (n *Layer) GetObjectTaggingAndLock(ctx context.Context, objVersion *data.ObjectVersion, nodeVersion *data.NodeVersion) (map[string]string, data.LockInfo, error) {
 	var err error
 	owner := n.BearerOwner(ctx)
 
diff --git a/api/layer/container.go b/api/layer/container.go
index 6c36b30..9077053 100644
--- a/api/layer/container.go
+++ b/api/layer/container.go
@@ -32,7 +32,7 @@ const (
 	AttributeLockEnabled        = "LockEnabled"
 )
 
-func (n *layer) containerInfo(ctx context.Context, prm PrmContainer) (*data.BucketInfo, error) {
+func (n *Layer) containerInfo(ctx context.Context, prm PrmContainer) (*data.BucketInfo, error) {
 	var (
 		err error
 		res *container.Container
@@ -87,7 +87,7 @@ func (n *layer) containerInfo(ctx context.Context, prm PrmContainer) (*data.Buck
 	return info, nil
 }
 
-func (n *layer) containerList(ctx context.Context) ([]*data.BucketInfo, error) {
+func (n *Layer) containerList(ctx context.Context) ([]*data.BucketInfo, error) {
 	stoken := n.SessionTokenForRead(ctx)
 
 	prm := PrmUserContainers{
@@ -119,7 +119,7 @@ func (n *layer) containerList(ctx context.Context) ([]*data.BucketInfo, error) {
 	return list, nil
 }
 
-func (n *layer) createContainer(ctx context.Context, p *CreateBucketParams) (*data.BucketInfo, error) {
+func (n *Layer) createContainer(ctx context.Context, p *CreateBucketParams) (*data.BucketInfo, error) {
 	if p.LocationConstraint == "" {
 		p.LocationConstraint = api.DefaultLocationConstraint // s3tests_boto3.functional.test_s3:test_bucket_get_location
 	}
@@ -173,13 +173,13 @@ func (n *layer) createContainer(ctx context.Context, p *CreateBucketParams) (*da
 	return bktInfo, nil
 }
 
-func (n *layer) setContainerEACLTable(ctx context.Context, idCnr cid.ID, table *eacl.Table, sessionToken *session.Container) error {
+func (n *Layer) setContainerEACLTable(ctx context.Context, idCnr cid.ID, table *eacl.Table, sessionToken *session.Container) error {
 	table.SetCID(idCnr)
 
 	return n.frostFS.SetContainerEACL(ctx, *table, sessionToken)
 }
 
-func (n *layer) GetContainerEACL(ctx context.Context, cnrID cid.ID) (*eacl.Table, error) {
+func (n *Layer) GetContainerEACL(ctx context.Context, cnrID cid.ID) (*eacl.Table, error) {
 	prm := PrmContainerEACL{
 		ContainerID:  cnrID,
 		SessionToken: n.SessionTokenForRead(ctx),
diff --git a/api/layer/cors.go b/api/layer/cors.go
index fcec02d..ce3c0c9 100644
--- a/api/layer/cors.go
+++ b/api/layer/cors.go
@@ -17,7 +17,7 @@ const wildcard = "*"
 
 var supportedMethods = map[string]struct{}{"GET": {}, "HEAD": {}, "POST": {}, "PUT": {}, "DELETE": {}}
 
-func (n *layer) PutBucketCORS(ctx context.Context, p *PutCORSParams) error {
+func (n *Layer) PutBucketCORS(ctx context.Context, p *PutCORSParams) error {
 	var (
 		buf  bytes.Buffer
 		tee  = io.TeeReader(p.Reader, &buf)
@@ -68,7 +68,7 @@ func (n *layer) PutBucketCORS(ctx context.Context, p *PutCORSParams) error {
 	return nil
 }
 
-func (n *layer) GetBucketCORS(ctx context.Context, bktInfo *data.BucketInfo) (*data.CORSConfiguration, error) {
+func (n *Layer) GetBucketCORS(ctx context.Context, bktInfo *data.BucketInfo) (*data.CORSConfiguration, error) {
 	cors, err := n.getCORS(ctx, bktInfo)
 	if err != nil {
 		if errorsStd.Is(err, ErrNodeNotFound) {
@@ -80,7 +80,7 @@ func (n *layer) GetBucketCORS(ctx context.Context, bktInfo *data.BucketInfo) (*d
 	return cors, nil
 }
 
-func (n *layer) DeleteBucketCORS(ctx context.Context, bktInfo *data.BucketInfo) error {
+func (n *Layer) DeleteBucketCORS(ctx context.Context, bktInfo *data.BucketInfo) error {
 	objID, err := n.treeService.DeleteBucketCORS(ctx, bktInfo)
 	objIDNotFound := errorsStd.Is(err, ErrNoNodeToRemove)
 	if err != nil && !objIDNotFound {
diff --git a/api/layer/layer.go b/api/layer/layer.go
index e81c3e4..ece8884 100644
--- a/api/layer/layer.go
+++ b/api/layer/layer.go
@@ -43,7 +43,7 @@ type (
 		FormContainerZone(ns string) (zone string, isDefault bool)
 	}
 
-	layer struct {
+	Layer struct {
 		frostFS     FrostFS
 		gateOwner   user.ID
 		log         *zap.Logger
@@ -199,64 +199,6 @@ type (
 		encrypted    bool
 		decryptedLen uint64
 	}
-
-	// Client provides S3 API client interface.
-	Client interface {
-		EphemeralKey() *keys.PublicKey
-
-		GetBucketSettings(ctx context.Context, bktInfo *data.BucketInfo) (*data.BucketSettings, error)
-		PutBucketSettings(ctx context.Context, p *PutSettingsParams) error
-
-		PutBucketCORS(ctx context.Context, p *PutCORSParams) error
-		GetBucketCORS(ctx context.Context, bktInfo *data.BucketInfo) (*data.CORSConfiguration, error)
-		DeleteBucketCORS(ctx context.Context, bktInfo *data.BucketInfo) error
-
-		ListBuckets(ctx context.Context) ([]*data.BucketInfo, error)
-		GetBucketInfo(ctx context.Context, name string) (*data.BucketInfo, error)
-		ResolveCID(ctx context.Context, name string) (cid.ID, error)
-		GetBucketACL(ctx context.Context, bktInfo *data.BucketInfo) (*BucketACL, error)
-		PutBucketACL(ctx context.Context, p *PutBucketACLParams) error
-		CreateBucket(ctx context.Context, p *CreateBucketParams) (*data.BucketInfo, error)
-		DeleteBucket(ctx context.Context, p *DeleteBucketParams) error
-
-		GetObject(ctx context.Context, p *GetObjectParams) (*ObjectPayload, error)
-		GetObjectInfo(ctx context.Context, p *HeadObjectParams) (*data.ObjectInfo, error)
-		GetExtendedObjectInfo(ctx context.Context, p *HeadObjectParams) (*data.ExtendedObjectInfo, error)
-
-		GetLockInfo(ctx context.Context, obj *data.ObjectVersion) (*data.LockInfo, error)
-		PutLockInfo(ctx context.Context, p *PutLockInfoParams) error
-
-		GetBucketTagging(ctx context.Context, bktInfo *data.BucketInfo) (map[string]string, error)
-		PutBucketTagging(ctx context.Context, bktInfo *data.BucketInfo, tagSet map[string]string) error
-		DeleteBucketTagging(ctx context.Context, bktInfo *data.BucketInfo) error
-
-		GetObjectTagging(ctx context.Context, p *data.GetObjectTaggingParams) (string, map[string]string, error)
-		PutObjectTagging(ctx context.Context, p *data.PutObjectTaggingParams) error
-		DeleteObjectTagging(ctx context.Context, p *data.ObjectVersion) error
-
-		PutObject(ctx context.Context, p *PutObjectParams) (*data.ExtendedObjectInfo, error)
-
-		CopyObject(ctx context.Context, p *CopyObjectParams) (*data.ExtendedObjectInfo, error)
-
-		ListObjectsV1(ctx context.Context, p *ListObjectsParamsV1) (*ListObjectsInfoV1, error)
-		ListObjectsV2(ctx context.Context, p *ListObjectsParamsV2) (*ListObjectsInfoV2, error)
-		ListObjectVersions(ctx context.Context, p *ListObjectVersionsParams) (*ListObjectVersionsInfo, error)
-
-		DeleteObjects(ctx context.Context, p *DeleteObjectParams) []*VersionedObject
-
-		CreateMultipartUpload(ctx context.Context, p *CreateMultipartParams) error
-		CompleteMultipartUpload(ctx context.Context, p *CompleteMultipartParams) (*UploadData, *data.ExtendedObjectInfo, error)
-		UploadPart(ctx context.Context, p *UploadPartParams) (string, error)
-		UploadPartCopy(ctx context.Context, p *UploadCopyParams) (*data.ObjectInfo, error)
-		ListMultipartUploads(ctx context.Context, p *ListMultipartUploadsParams) (*ListMultipartUploadsInfo, error)
-		AbortMultipartUpload(ctx context.Context, p *UploadInfoParams) error
-		ListParts(ctx context.Context, p *ListPartsParams) (*ListPartsInfo, error)
-
-		// Compound methods for optimizations
-
-		// GetObjectTaggingAndLock unifies GetObjectTagging and GetLock methods in single tree service invocation.
-		GetObjectTaggingAndLock(ctx context.Context, p *data.ObjectVersion, nodeVersion *data.NodeVersion) (map[string]string, data.LockInfo, error)
-	}
 )
 
 const (
@@ -287,10 +229,10 @@ func (p HeadObjectParams) Versioned() bool {
 	return len(p.VersionID) > 0
 }
 
-// NewLayer creates an instance of a layer. It checks credentials
+// NewLayer creates an instance of a Layer. It checks credentials
 // and establishes gRPC connection with the node.
-func NewLayer(log *zap.Logger, frostFS FrostFS, config *Config) Client {
-	return &layer{
+func NewLayer(log *zap.Logger, frostFS FrostFS, config *Config) *Layer {
+	return &Layer{
 		frostFS:     frostFS,
 		log:         log,
 		gateOwner:   config.GateOwner,
@@ -302,7 +244,7 @@ func NewLayer(log *zap.Logger, frostFS FrostFS, config *Config) Client {
 	}
 }
 
-func (n *layer) EphemeralKey() *keys.PublicKey {
+func (n *Layer) EphemeralKey() *keys.PublicKey {
 	return n.anonKey.Key.PublicKey()
 }
 
@@ -322,7 +264,7 @@ func TimeNow(ctx context.Context) time.Time {
 }
 
 // BearerOwner returns owner id from BearerToken (context) or from client owner.
-func (n *layer) BearerOwner(ctx context.Context) user.ID {
+func (n *Layer) BearerOwner(ctx context.Context) user.ID {
 	if bd, err := middleware.GetBoxData(ctx); err == nil && bd.Gate.BearerToken != nil {
 		return bearer.ResolveIssuer(*bd.Gate.BearerToken)
 	}
@@ -334,7 +276,7 @@ func (n *layer) BearerOwner(ctx context.Context) user.ID {
 }
 
 // SessionTokenForRead returns session container token.
-func (n *layer) SessionTokenForRead(ctx context.Context) *session.Container {
+func (n *Layer) SessionTokenForRead(ctx context.Context) *session.Container {
 	if bd, err := middleware.GetBoxData(ctx); err == nil && bd.Gate != nil {
 		return bd.Gate.SessionToken()
 	}
@@ -342,7 +284,7 @@ func (n *layer) SessionTokenForRead(ctx context.Context) *session.Container {
 	return nil
 }
 
-func (n *layer) reqLogger(ctx context.Context) *zap.Logger {
+func (n *Layer) reqLogger(ctx context.Context) *zap.Logger {
 	reqLogger := middleware.GetReqLog(ctx)
 	if reqLogger != nil {
 		return reqLogger
@@ -350,7 +292,7 @@ func (n *layer) reqLogger(ctx context.Context) *zap.Logger {
 	return n.log
 }
 
-func (n *layer) prepareAuthParameters(ctx context.Context, prm *PrmAuth, bktOwner user.ID) {
+func (n *Layer) prepareAuthParameters(ctx context.Context, prm *PrmAuth, bktOwner user.ID) {
 	if bd, err := middleware.GetBoxData(ctx); err == nil && bd.Gate.BearerToken != nil {
 		if bd.Gate.BearerToken.Impersonate() || bktOwner.Equals(bearer.ResolveIssuer(*bd.Gate.BearerToken)) {
 			prm.BearerToken = bd.Gate.BearerToken
@@ -362,7 +304,7 @@ func (n *layer) prepareAuthParameters(ctx context.Context, prm *PrmAuth, bktOwne
 }
 
 // GetBucketInfo returns bucket info by name.
-func (n *layer) GetBucketInfo(ctx context.Context, name string) (*data.BucketInfo, error) {
+func (n *Layer) GetBucketInfo(ctx context.Context, name string) (*data.BucketInfo, error) {
 	name, err := url.QueryUnescape(name)
 	if err != nil {
 		return nil, fmt.Errorf("unescape bucket name: %w", err)
@@ -392,7 +334,7 @@ func (n *layer) GetBucketInfo(ctx context.Context, name string) (*data.BucketInf
 }
 
 // ResolveCID returns container id by name.
-func (n *layer) ResolveCID(ctx context.Context, name string) (cid.ID, error) {
+func (n *Layer) ResolveCID(ctx context.Context, name string) (cid.ID, error) {
 	name, err := url.QueryUnescape(name)
 	if err != nil {
 		return cid.ID{}, fmt.Errorf("unescape bucket name: %w", err)
@@ -409,7 +351,7 @@ func (n *layer) ResolveCID(ctx context.Context, name string) (cid.ID, error) {
 }
 
 // GetBucketACL returns bucket acl info by name.
-func (n *layer) GetBucketACL(ctx context.Context, bktInfo *data.BucketInfo) (*BucketACL, error) {
+func (n *Layer) GetBucketACL(ctx context.Context, bktInfo *data.BucketInfo) (*BucketACL, error) {
 	eACL, err := n.GetContainerEACL(ctx, bktInfo.CID)
 	if err != nil {
 		return nil, fmt.Errorf("get container eacl: %w", err)
@@ -422,18 +364,18 @@ func (n *layer) GetBucketACL(ctx context.Context, bktInfo *data.BucketInfo) (*Bu
 }
 
 // PutBucketACL puts bucket acl by name.
-func (n *layer) PutBucketACL(ctx context.Context, param *PutBucketACLParams) error {
+func (n *Layer) PutBucketACL(ctx context.Context, param *PutBucketACLParams) error {
 	return n.setContainerEACLTable(ctx, param.BktInfo.CID, param.EACL, param.SessionToken)
 }
 
 // ListBuckets returns all user containers. The name of the bucket is a container
 // id. Timestamp is omitted since it is not saved in frostfs container.
-func (n *layer) ListBuckets(ctx context.Context) ([]*data.BucketInfo, error) {
+func (n *Layer) ListBuckets(ctx context.Context) ([]*data.BucketInfo, error) {
 	return n.containerList(ctx)
 }
 
 // GetObject from storage.
-func (n *layer) GetObject(ctx context.Context, p *GetObjectParams) (*ObjectPayload, error) {
+func (n *Layer) GetObject(ctx context.Context, p *GetObjectParams) (*ObjectPayload, error) {
 	var params getParams
 
 	params.objInfo = p.ObjectInfo
@@ -547,7 +489,7 @@ func getDecrypter(p *GetObjectParams) (*encryption.Decrypter, error) {
 }
 
 // GetObjectInfo returns meta information about the object.
-func (n *layer) GetObjectInfo(ctx context.Context, p *HeadObjectParams) (*data.ObjectInfo, error) {
+func (n *Layer) GetObjectInfo(ctx context.Context, p *HeadObjectParams) (*data.ObjectInfo, error) {
 	extendedObjectInfo, err := n.GetExtendedObjectInfo(ctx, p)
 	if err != nil {
 		return nil, err
@@ -557,7 +499,7 @@ func (n *layer) GetObjectInfo(ctx context.Context, p *HeadObjectParams) (*data.O
 }
 
 // GetExtendedObjectInfo returns meta information and corresponding info from the tree service about the object.
-func (n *layer) GetExtendedObjectInfo(ctx context.Context, p *HeadObjectParams) (*data.ExtendedObjectInfo, error) {
+func (n *Layer) GetExtendedObjectInfo(ctx context.Context, p *HeadObjectParams) (*data.ExtendedObjectInfo, error) {
 	var objInfo *data.ExtendedObjectInfo
 	var err error
 
@@ -578,7 +520,7 @@ func (n *layer) GetExtendedObjectInfo(ctx context.Context, p *HeadObjectParams)
 }
 
 // CopyObject from one bucket into another bucket.
-func (n *layer) CopyObject(ctx context.Context, p *CopyObjectParams) (*data.ExtendedObjectInfo, error) {
+func (n *Layer) CopyObject(ctx context.Context, p *CopyObjectParams) (*data.ExtendedObjectInfo, error) {
 	objPayload, err := n.GetObject(ctx, &GetObjectParams{
 		ObjectInfo: p.SrcObject,
 		Versioned:  p.SrcVersioned,
@@ -612,7 +554,7 @@ func getRandomOID() (oid.ID, error) {
 	return objID, nil
 }
 
-func (n *layer) deleteObject(ctx context.Context, bkt *data.BucketInfo, settings *data.BucketSettings, obj *VersionedObject) *VersionedObject {
+func (n *Layer) deleteObject(ctx context.Context, bkt *data.BucketInfo, settings *data.BucketSettings, obj *VersionedObject) *VersionedObject {
 	if len(obj.VersionID) != 0 || settings.Unversioned() {
 		var nodeVersion *data.NodeVersion
 		if nodeVersion, obj.Error = n.getNodeVersionToDelete(ctx, bkt, obj); obj.Error != nil {
@@ -688,7 +630,7 @@ func (n *layer) deleteObject(ctx context.Context, bkt *data.BucketInfo, settings
 	return obj
 }
 
-func (n *layer) handleNotFoundError(bkt *data.BucketInfo, obj *VersionedObject) *VersionedObject {
+func (n *Layer) handleNotFoundError(bkt *data.BucketInfo, obj *VersionedObject) *VersionedObject {
 	if isNotFoundError(obj.Error) {
 		obj.Error = nil
 		n.cache.CleanListCacheEntriesContainingObject(obj.Name, bkt.CID)
@@ -698,7 +640,7 @@ func (n *layer) handleNotFoundError(bkt *data.BucketInfo, obj *VersionedObject)
 	return obj
 }
 
-func (n *layer) handleObjectDeleteErrors(ctx context.Context, bkt *data.BucketInfo, obj *VersionedObject, nodeID uint64) *VersionedObject {
+func (n *Layer) handleObjectDeleteErrors(ctx context.Context, bkt *data.BucketInfo, obj *VersionedObject, nodeID uint64) *VersionedObject {
 	if !client.IsErrObjectAlreadyRemoved(obj.Error) && !client.IsErrObjectNotFound(obj.Error) {
 		return obj
 	}
@@ -719,7 +661,7 @@ func isNotFoundError(err error) bool {
 		errors.IsS3Error(err, errors.ErrNoSuchVersion)
 }
 
-func (n *layer) getNodeVersionToDelete(ctx context.Context, bkt *data.BucketInfo, obj *VersionedObject) (*data.NodeVersion, error) {
+func (n *Layer) getNodeVersionToDelete(ctx context.Context, bkt *data.BucketInfo, obj *VersionedObject) (*data.NodeVersion, error) {
 	objVersion := &data.ObjectVersion{
 		BktInfo:               bkt,
 		ObjectName:            obj.Name,
@@ -730,7 +672,7 @@ func (n *layer) getNodeVersionToDelete(ctx context.Context, bkt *data.BucketInfo
 	return n.getNodeVersion(ctx, objVersion)
 }
 
-func (n *layer) getLastNodeVersion(ctx context.Context, bkt *data.BucketInfo, obj *VersionedObject) (*data.NodeVersion, error) {
+func (n *Layer) getLastNodeVersion(ctx context.Context, bkt *data.BucketInfo, obj *VersionedObject) (*data.NodeVersion, error) {
 	objVersion := &data.ObjectVersion{
 		BktInfo:               bkt,
 		ObjectName:            obj.Name,
@@ -741,7 +683,7 @@ func (n *layer) getLastNodeVersion(ctx context.Context, bkt *data.BucketInfo, ob
 	return n.getNodeVersion(ctx, objVersion)
 }
 
-func (n *layer) removeOldVersion(ctx context.Context, bkt *data.BucketInfo, nodeVersion *data.NodeVersion, obj *VersionedObject) (string, error) {
+func (n *Layer) removeOldVersion(ctx context.Context, bkt *data.BucketInfo, nodeVersion *data.NodeVersion, obj *VersionedObject) (string, error) {
 	if nodeVersion.IsDeleteMarker {
 		return obj.VersionID, nil
 	}
@@ -753,7 +695,7 @@ func (n *layer) removeOldVersion(ctx context.Context, bkt *data.BucketInfo, node
 	return "", n.objectDelete(ctx, bkt, nodeVersion.OID)
 }
 
-func (n *layer) removeCombinedObject(ctx context.Context, bkt *data.BucketInfo, nodeVersion *data.NodeVersion) error {
+func (n *Layer) removeCombinedObject(ctx context.Context, bkt *data.BucketInfo, nodeVersion *data.NodeVersion) error {
 	combinedObj, err := n.objectGet(ctx, bkt, nodeVersion.OID)
 	if err != nil {
 		return fmt.Errorf("get combined object '%s': %w", nodeVersion.OID.EncodeToString(), err)
@@ -781,7 +723,7 @@ func (n *layer) removeCombinedObject(ctx context.Context, bkt *data.BucketInfo,
 }
 
 // DeleteObjects from the storage.
-func (n *layer) DeleteObjects(ctx context.Context, p *DeleteObjectParams) []*VersionedObject {
+func (n *Layer) DeleteObjects(ctx context.Context, p *DeleteObjectParams) []*VersionedObject {
 	for i, obj := range p.Objects {
 		p.Objects[i] = n.deleteObject(ctx, p.BktInfo, p.Settings, obj)
 		if p.IsMultiple && p.Objects[i].Error != nil {
@@ -792,7 +734,7 @@ func (n *layer) DeleteObjects(ctx context.Context, p *DeleteObjectParams) []*Ver
 	return p.Objects
 }
 
-func (n *layer) CreateBucket(ctx context.Context, p *CreateBucketParams) (*data.BucketInfo, error) {
+func (n *Layer) CreateBucket(ctx context.Context, p *CreateBucketParams) (*data.BucketInfo, error) {
 	bktInfo, err := n.GetBucketInfo(ctx, p.Name)
 	if err != nil {
 		if errors.IsS3Error(err, errors.ErrNoSuchBucket) {
@@ -808,7 +750,7 @@ func (n *layer) CreateBucket(ctx context.Context, p *CreateBucketParams) (*data.
 	return nil, errors.GetAPIError(errors.ErrBucketAlreadyExists)
 }
 
-func (n *layer) ResolveBucket(ctx context.Context, name string) (cid.ID, error) {
+func (n *Layer) ResolveBucket(ctx context.Context, name string) (cid.ID, error) {
 	var cnrID cid.ID
 	if err := cnrID.DecodeString(name); err != nil {
 		if cnrID, err = n.resolver.Resolve(ctx, name); err != nil {
@@ -821,7 +763,7 @@ func (n *layer) ResolveBucket(ctx context.Context, name string) (cid.ID, error)
 	return cnrID, nil
 }
 
-func (n *layer) DeleteBucket(ctx context.Context, p *DeleteBucketParams) error {
+func (n *Layer) DeleteBucket(ctx context.Context, p *DeleteBucketParams) error {
 	res, _, err := n.getAllObjectsVersions(ctx, commonVersionsListingParams{
 		BktInfo: p.BktInfo,
 		MaxKeys: 1,
diff --git a/api/layer/listing.go b/api/layer/listing.go
index cda75d1..c72177f 100644
--- a/api/layer/listing.go
+++ b/api/layer/listing.go
@@ -96,7 +96,7 @@ const (
 )
 
 // ListObjectsV1 returns objects in a bucket for requests of Version 1.
-func (n *layer) ListObjectsV1(ctx context.Context, p *ListObjectsParamsV1) (*ListObjectsInfoV1, error) {
+func (n *Layer) ListObjectsV1(ctx context.Context, p *ListObjectsParamsV1) (*ListObjectsInfoV1, error) {
 	var result ListObjectsInfoV1
 
 	prm := commonLatestVersionsListingParams{
@@ -127,7 +127,7 @@ func (n *layer) ListObjectsV1(ctx context.Context, p *ListObjectsParamsV1) (*Lis
 }
 
 // ListObjectsV2 returns objects in a bucket for requests of Version 2.
-func (n *layer) ListObjectsV2(ctx context.Context, p *ListObjectsParamsV2) (*ListObjectsInfoV2, error) {
+func (n *Layer) ListObjectsV2(ctx context.Context, p *ListObjectsParamsV2) (*ListObjectsInfoV2, error) {
 	var result ListObjectsInfoV2
 
 	prm := commonLatestVersionsListingParams{
@@ -157,7 +157,7 @@ func (n *layer) ListObjectsV2(ctx context.Context, p *ListObjectsParamsV2) (*Lis
 	return &result, nil
 }
 
-func (n *layer) ListObjectVersions(ctx context.Context, p *ListObjectVersionsParams) (*ListObjectVersionsInfo, error) {
+func (n *Layer) ListObjectVersions(ctx context.Context, p *ListObjectVersionsParams) (*ListObjectVersionsInfo, error) {
 	prm := commonVersionsListingParams{
 		BktInfo:   p.BktInfo,
 		Delimiter: p.Delimiter,
@@ -188,7 +188,7 @@ func (n *layer) ListObjectVersions(ctx context.Context, p *ListObjectVersionsPar
 	return res, nil
 }
 
-func (n *layer) getLatestObjectsVersions(ctx context.Context, p commonLatestVersionsListingParams) (objects []*data.ExtendedNodeVersion, next *data.ExtendedNodeVersion, err error) {
+func (n *Layer) getLatestObjectsVersions(ctx context.Context, p commonLatestVersionsListingParams) (objects []*data.ExtendedNodeVersion, next *data.ExtendedNodeVersion, err error) {
 	if p.MaxKeys == 0 {
 		return nil, nil, nil
 	}
@@ -225,7 +225,7 @@ func (n *layer) getLatestObjectsVersions(ctx context.Context, p commonLatestVers
 	return
 }
 
-func (n *layer) getAllObjectsVersions(ctx context.Context, p commonVersionsListingParams) ([]*data.ExtendedNodeVersion, bool, error) {
+func (n *Layer) getAllObjectsVersions(ctx context.Context, p commonVersionsListingParams) ([]*data.ExtendedNodeVersion, bool, error) {
 	if p.MaxKeys == 0 {
 		return nil, false, nil
 	}
@@ -301,15 +301,15 @@ func formVersionsListRow(objects []*data.ExtendedNodeVersion, rowStartIndex int,
 	}
 }
 
-func (n *layer) getListLatestVersionsSession(ctx context.Context, p commonLatestVersionsListingParams) (*data.ListSession, error) {
+func (n *Layer) getListLatestVersionsSession(ctx context.Context, p commonLatestVersionsListingParams) (*data.ListSession, error) {
 	return n.getListVersionsSession(ctx, p.commonVersionsListingParams, true)
 }
 
-func (n *layer) getListAllVersionsSession(ctx context.Context, p commonVersionsListingParams) (*data.ListSession, error) {
+func (n *Layer) getListAllVersionsSession(ctx context.Context, p commonVersionsListingParams) (*data.ListSession, error) {
 	return n.getListVersionsSession(ctx, p, false)
 }
 
-func (n *layer) getListVersionsSession(ctx context.Context, p commonVersionsListingParams, latestOnly bool) (*data.ListSession, error) {
+func (n *Layer) getListVersionsSession(ctx context.Context, p commonVersionsListingParams, latestOnly bool) (*data.ListSession, error) {
 	owner := n.BearerOwner(ctx)
 
 	cacheKey := cache.CreateListSessionCacheKey(p.BktInfo.CID, p.Prefix, p.Bookmark)
@@ -329,7 +329,7 @@ func (n *layer) getListVersionsSession(ctx context.Context, p commonVersionsList
 	return session, nil
 }
 
-func (n *layer) initNewVersionsByPrefixSession(ctx context.Context, p commonVersionsListingParams, latestOnly bool) (session *data.ListSession, err error) {
+func (n *Layer) initNewVersionsByPrefixSession(ctx context.Context, p commonVersionsListingParams, latestOnly bool) (session *data.ListSession, err error) {
 	session = &data.ListSession{NamesMap: make(map[string]struct{})}
 	session.Context, session.Cancel = context.WithCancel(context.Background())
 
@@ -345,7 +345,7 @@ func (n *layer) initNewVersionsByPrefixSession(ctx context.Context, p commonVers
 	return session, nil
 }
 
-func (n *layer) putListLatestVersionsSession(ctx context.Context, p commonLatestVersionsListingParams, session *data.ListSession, allObjects []*data.ExtendedNodeVersion) {
+func (n *Layer) putListLatestVersionsSession(ctx context.Context, p commonLatestVersionsListingParams, session *data.ListSession, allObjects []*data.ExtendedNodeVersion) {
 	if len(allObjects) <= p.MaxKeys {
 		return
 	}
@@ -366,7 +366,7 @@ func (n *layer) putListLatestVersionsSession(ctx context.Context, p commonLatest
 	n.cache.PutListSession(n.BearerOwner(ctx), cacheKey, session)
 }
 
-func (n *layer) putListAllVersionsSession(ctx context.Context, p commonVersionsListingParams, session *data.ListSession, allObjects []*data.ExtendedNodeVersion) {
+func (n *Layer) putListAllVersionsSession(ctx context.Context, p commonVersionsListingParams, session *data.ListSession, allObjects []*data.ExtendedNodeVersion) {
 	if len(allObjects) <= p.MaxKeys {
 		return
 	}
@@ -498,7 +498,7 @@ func nodesGeneratorVersions(ctx context.Context, p commonVersionsListingParams,
 	return nodeCh, errCh
 }
 
-func (n *layer) initWorkerPool(ctx context.Context, size int, p commonVersionsListingParams, input <-chan *data.ExtendedNodeVersion) (<-chan *data.ExtendedNodeVersion, error) {
+func (n *Layer) initWorkerPool(ctx context.Context, size int, p commonVersionsListingParams, input <-chan *data.ExtendedNodeVersion) (<-chan *data.ExtendedNodeVersion, error) {
 	reqLog := n.reqLogger(ctx)
 	pool, err := ants.NewPool(size, ants.WithLogger(&logWrapper{reqLog}))
 	if err != nil {
@@ -637,7 +637,7 @@ func triageExtendedObjects(allObjects []*data.ExtendedNodeVersion) (prefixes []s
 	return
 }
 
-func (n *layer) objectInfoFromObjectsCacheOrFrostFS(ctx context.Context, bktInfo *data.BucketInfo, node *data.NodeVersion) (oi *data.ObjectInfo) {
+func (n *Layer) objectInfoFromObjectsCacheOrFrostFS(ctx context.Context, bktInfo *data.BucketInfo, node *data.NodeVersion) (oi *data.ObjectInfo) {
 	owner := n.BearerOwner(ctx)
 	if extInfo := n.cache.GetObject(owner, newAddress(bktInfo.CID, node.OID)); extInfo != nil {
 		return extInfo.ObjectInfo
diff --git a/api/layer/multipart_upload.go b/api/layer/multipart_upload.go
index 23aaa63..6c89d90 100644
--- a/api/layer/multipart_upload.go
+++ b/api/layer/multipart_upload.go
@@ -146,7 +146,7 @@ type (
 	}
 )
 
-func (n *layer) CreateMultipartUpload(ctx context.Context, p *CreateMultipartParams) error {
+func (n *Layer) CreateMultipartUpload(ctx context.Context, p *CreateMultipartParams) error {
 	metaSize := len(p.Header)
 	if p.Data != nil {
 		metaSize += len(p.Data.ACLHeaders)
@@ -185,7 +185,7 @@ func (n *layer) CreateMultipartUpload(ctx context.Context, p *CreateMultipartPar
 	return n.treeService.CreateMultipartUpload(ctx, p.Info.Bkt, info)
 }
 
-func (n *layer) UploadPart(ctx context.Context, p *UploadPartParams) (string, error) {
+func (n *Layer) UploadPart(ctx context.Context, p *UploadPartParams) (string, error) {
 	multipartInfo, err := n.treeService.GetMultipartUpload(ctx, p.Info.Bkt, p.Info.Key, p.Info.UploadID)
 	if err != nil {
 		if errors.Is(err, ErrNodeNotFound) {
@@ -206,7 +206,7 @@ func (n *layer) UploadPart(ctx context.Context, p *UploadPartParams) (string, er
 	return objInfo.ETag(n.features.MD5Enabled()), nil
 }
 
-func (n *layer) uploadPart(ctx context.Context, multipartInfo *data.MultipartInfo, p *UploadPartParams) (*data.ObjectInfo, error) {
+func (n *Layer) uploadPart(ctx context.Context, multipartInfo *data.MultipartInfo, p *UploadPartParams) (*data.ObjectInfo, error) {
 	encInfo := FormEncryptionInfo(multipartInfo.Meta)
 	if err := p.Info.Encryption.MatchObjectEncryption(encInfo); err != nil {
 		n.reqLogger(ctx).Warn(logs.MismatchedObjEncryptionInfo, zap.Error(err))
@@ -319,7 +319,7 @@ func (n *layer) uploadPart(ctx context.Context, multipartInfo *data.MultipartInf
 	return objInfo, nil
 }
 
-func (n *layer) UploadPartCopy(ctx context.Context, p *UploadCopyParams) (*data.ObjectInfo, error) {
+func (n *Layer) UploadPartCopy(ctx context.Context, p *UploadCopyParams) (*data.ObjectInfo, error) {
 	multipartInfo, err := n.treeService.GetMultipartUpload(ctx, p.Info.Bkt, p.Info.Key, p.Info.UploadID)
 	if err != nil {
 		if errors.Is(err, ErrNodeNotFound) {
@@ -367,7 +367,7 @@ func (n *layer) UploadPartCopy(ctx context.Context, p *UploadCopyParams) (*data.
 	return n.uploadPart(ctx, multipartInfo, params)
 }
 
-func (n *layer) CompleteMultipartUpload(ctx context.Context, p *CompleteMultipartParams) (*UploadData, *data.ExtendedObjectInfo, error) {
+func (n *Layer) CompleteMultipartUpload(ctx context.Context, p *CompleteMultipartParams) (*UploadData, *data.ExtendedObjectInfo, error) {
 	for i := 1; i < len(p.Parts); i++ {
 		if p.Parts[i].PartNumber <= p.Parts[i-1].PartNumber {
 			return nil, nil, s3errors.GetAPIError(s3errors.ErrInvalidPartOrder)
@@ -492,7 +492,7 @@ func (n *layer) CompleteMultipartUpload(ctx context.Context, p *CompleteMultipar
 	return uploadData, extObjInfo, n.treeService.DeleteMultipartUpload(ctx, p.Info.Bkt, multipartInfo)
 }
 
-func (n *layer) ListMultipartUploads(ctx context.Context, p *ListMultipartUploadsParams) (*ListMultipartUploadsInfo, error) {
+func (n *Layer) ListMultipartUploads(ctx context.Context, p *ListMultipartUploadsParams) (*ListMultipartUploadsInfo, error) {
 	var result ListMultipartUploadsInfo
 	if p.MaxUploads == 0 {
 		return &result, nil
@@ -552,7 +552,7 @@ func (n *layer) ListMultipartUploads(ctx context.Context, p *ListMultipartUpload
 	return &result, nil
 }
 
-func (n *layer) AbortMultipartUpload(ctx context.Context, p *UploadInfoParams) error {
+func (n *Layer) AbortMultipartUpload(ctx context.Context, p *UploadInfoParams) error {
 	multipartInfo, parts, err := n.getUploadParts(ctx, p)
 	if err != nil {
 		return err
@@ -568,7 +568,7 @@ func (n *layer) AbortMultipartUpload(ctx context.Context, p *UploadInfoParams) e
 	return n.treeService.DeleteMultipartUpload(ctx, p.Bkt, multipartInfo)
 }
 
-func (n *layer) ListParts(ctx context.Context, p *ListPartsParams) (*ListPartsInfo, error) {
+func (n *Layer) ListParts(ctx context.Context, p *ListPartsParams) (*ListPartsInfo, error) {
 	var res ListPartsInfo
 	multipartInfo, partsInfo, err := n.getUploadParts(ctx, p.Info)
 	if err != nil {
@@ -622,7 +622,7 @@ func (n *layer) ListParts(ctx context.Context, p *ListPartsParams) (*ListPartsIn
 	return &res, nil
 }
 
-func (n *layer) getUploadParts(ctx context.Context, p *UploadInfoParams) (*data.MultipartInfo, map[int]*data.PartInfo, error) {
+func (n *Layer) getUploadParts(ctx context.Context, p *UploadInfoParams) (*data.MultipartInfo, map[int]*data.PartInfo, error) {
 	multipartInfo, err := n.treeService.GetMultipartUpload(ctx, p.Bkt, p.Key, p.UploadID)
 	if err != nil {
 		if errors.Is(err, ErrNodeNotFound) {
diff --git a/api/layer/object.go b/api/layer/object.go
index eb5412c..b8625b3 100644
--- a/api/layer/object.go
+++ b/api/layer/object.go
@@ -67,7 +67,7 @@ func newAddress(cnr cid.ID, obj oid.ID) oid.Address {
 }
 
 // objectHead returns all object's headers.
-func (n *layer) objectHead(ctx context.Context, bktInfo *data.BucketInfo, idObj oid.ID) (*object.Object, error) {
+func (n *Layer) objectHead(ctx context.Context, bktInfo *data.BucketInfo, idObj oid.ID) (*object.Object, error) {
 	prm := PrmObjectRead{
 		Container:  bktInfo.CID,
 		Object:     idObj,
@@ -84,7 +84,7 @@ func (n *layer) objectHead(ctx context.Context, bktInfo *data.BucketInfo, idObj
 	return res.Head, nil
 }
 
-func (n *layer) initObjectPayloadReader(ctx context.Context, p getParams) (io.Reader, error) {
+func (n *Layer) initObjectPayloadReader(ctx context.Context, p getParams) (io.Reader, error) {
 	if _, isCombined := p.objInfo.Headers[MultipartObjectSize]; !isCombined {
 		return n.initFrostFSObjectPayloadReader(ctx, getFrostFSParams{
 			off:     p.off,
@@ -131,7 +131,7 @@ func (n *layer) initObjectPayloadReader(ctx context.Context, p getParams) (io.Re
 
 // initializes payload reader of the FrostFS object.
 // Zero range corresponds to full payload (panics if only offset is set).
-func (n *layer) initFrostFSObjectPayloadReader(ctx context.Context, p getFrostFSParams) (io.Reader, error) {
+func (n *Layer) initFrostFSObjectPayloadReader(ctx context.Context, p getFrostFSParams) (io.Reader, error) {
 	prm := PrmObjectRead{
 		Container:    p.bktInfo.CID,
 		Object:       p.oid,
@@ -150,7 +150,7 @@ func (n *layer) initFrostFSObjectPayloadReader(ctx context.Context, p getFrostFS
 }
 
 // objectGet returns an object with payload in the object.
-func (n *layer) objectGet(ctx context.Context, bktInfo *data.BucketInfo, objID oid.ID) (*object.Object, error) {
+func (n *Layer) objectGet(ctx context.Context, bktInfo *data.BucketInfo, objID oid.ID) (*object.Object, error) {
 	prm := PrmObjectRead{
 		Container:   bktInfo.CID,
 		Object:      objID,
@@ -214,7 +214,7 @@ func ParseCompletedPartHeader(hdr string) (*Part, error) {
 }
 
 // PutObject stores object into FrostFS, took payload from io.Reader.
-func (n *layer) PutObject(ctx context.Context, p *PutObjectParams) (*data.ExtendedObjectInfo, error) {
+func (n *Layer) PutObject(ctx context.Context, p *PutObjectParams) (*data.ExtendedObjectInfo, error) {
 	bktSettings, err := n.GetBucketSettings(ctx, p.BktInfo)
 	if err != nil {
 		return nil, fmt.Errorf("couldn't get versioning settings object: %w", err)
@@ -363,7 +363,7 @@ func (n *layer) PutObject(ctx context.Context, p *PutObjectParams) (*data.Extend
 	return extendedObjInfo, nil
 }
 
-func (n *layer) headLastVersionIfNotDeleted(ctx context.Context, bkt *data.BucketInfo, objectName string) (*data.ExtendedObjectInfo, error) {
+func (n *Layer) headLastVersionIfNotDeleted(ctx context.Context, bkt *data.BucketInfo, objectName string) (*data.ExtendedObjectInfo, error) {
 	owner := n.BearerOwner(ctx)
 	if extObjInfo := n.cache.GetLastObject(owner, bkt.Name, objectName); extObjInfo != nil {
 		return extObjInfo, nil
@@ -401,7 +401,7 @@ func (n *layer) headLastVersionIfNotDeleted(ctx context.Context, bkt *data.Bucke
 	return extObjInfo, nil
 }
 
-func (n *layer) headVersion(ctx context.Context, bkt *data.BucketInfo, p *HeadObjectParams) (*data.ExtendedObjectInfo, error) {
+func (n *Layer) headVersion(ctx context.Context, bkt *data.BucketInfo, p *HeadObjectParams) (*data.ExtendedObjectInfo, error) {
 	var err error
 	var foundVersion *data.NodeVersion
 	if p.VersionID == data.UnversionedObjectVersionID {
@@ -459,7 +459,7 @@ func (n *layer) headVersion(ctx context.Context, bkt *data.BucketInfo, p *HeadOb
 }
 
 // objectDelete puts tombstone object into frostfs.
-func (n *layer) objectDelete(ctx context.Context, bktInfo *data.BucketInfo, idObj oid.ID) error {
+func (n *Layer) objectDelete(ctx context.Context, bktInfo *data.BucketInfo, idObj oid.ID) error {
 	prm := PrmObjectDelete{
 		Container: bktInfo.CID,
 		Object:    idObj,
@@ -474,7 +474,7 @@ func (n *layer) objectDelete(ctx context.Context, bktInfo *data.BucketInfo, idOb
 
 // objectPutAndHash prepare auth parameters and invoke frostfs.CreateObject.
 // Returns object ID and payload sha256 hash.
-func (n *layer) objectPutAndHash(ctx context.Context, prm PrmObjectCreate, bktInfo *data.BucketInfo) (uint64, oid.ID, []byte, []byte, error) {
+func (n *Layer) objectPutAndHash(ctx context.Context, prm PrmObjectCreate, bktInfo *data.BucketInfo) (uint64, oid.ID, []byte, []byte, error) {
 	n.prepareAuthParameters(ctx, &prm.PrmAuth, bktInfo.Owner)
 	prm.ClientCut = n.features.ClientCut()
 	prm.BufferMaxSize = n.features.BufferMaxSizeForPut()
diff --git a/api/layer/object_test.go b/api/layer/object_test.go
index 2666577..21c8d2e 100644
--- a/api/layer/object_test.go
+++ b/api/layer/object_test.go
@@ -31,8 +31,6 @@ func TestWrapReader(t *testing.T) {
 
 func TestGoroutinesDontLeakInPutAndHash(t *testing.T) {
 	tc := prepareContext(t)
-	l, ok := tc.layer.(*layer)
-	require.True(t, ok)
 
 	content := make([]byte, 128*1024)
 	_, err := rand.Read(content)
@@ -46,7 +44,7 @@ func TestGoroutinesDontLeakInPutAndHash(t *testing.T) {
 
 	expErr := errors.New("some error")
 	tc.testFrostFS.SetObjectPutError(tc.obj, expErr)
-	_, _, _, _, err = l.objectPutAndHash(tc.ctx, prm, tc.bktInfo)
+	_, _, _, _, err = tc.layer.objectPutAndHash(tc.ctx, prm, tc.bktInfo)
 	require.ErrorIs(t, err, expErr)
 	require.Empty(t, payload.Len(), "body must be read out otherwise goroutines can leak in wrapReader")
 }
diff --git a/api/layer/system_object.go b/api/layer/system_object.go
index 1100072..aa5fa9c 100644
--- a/api/layer/system_object.go
+++ b/api/layer/system_object.go
@@ -26,7 +26,7 @@ type PutLockInfoParams struct {
 	NodeVersion   *data.NodeVersion // optional
 }
 
-func (n *layer) PutLockInfo(ctx context.Context, p *PutLockInfoParams) (err error) {
+func (n *Layer) PutLockInfo(ctx context.Context, p *PutLockInfoParams) (err error) {
 	newLock := p.NewLock
 	versionNode := p.NodeVersion
 	// sometimes node version can be provided from executing context
@@ -100,7 +100,7 @@ func (n *layer) PutLockInfo(ctx context.Context, p *PutLockInfoParams) (err erro
 	return nil
 }
 
-func (n *layer) getNodeVersionFromCacheOrFrostfs(ctx context.Context, objVersion *data.ObjectVersion) (nodeVersion *data.NodeVersion, err error) {
+func (n *Layer) getNodeVersionFromCacheOrFrostfs(ctx context.Context, objVersion *data.ObjectVersion) (nodeVersion *data.NodeVersion, err error) {
 	// check cache if node version is stored inside extendedObjectVersion
 	nodeVersion = n.getNodeVersionFromCache(n.BearerOwner(ctx), objVersion)
 	if nodeVersion == nil {
@@ -111,7 +111,7 @@ func (n *layer) getNodeVersionFromCacheOrFrostfs(ctx context.Context, objVersion
 	return nodeVersion, nil
 }
 
-func (n *layer) putLockObject(ctx context.Context, bktInfo *data.BucketInfo, objID oid.ID, lock *data.ObjectLock, copiesNumber []uint32) (oid.ID, error) {
+func (n *Layer) putLockObject(ctx context.Context, bktInfo *data.BucketInfo, objID oid.ID, lock *data.ObjectLock, copiesNumber []uint32) (oid.ID, error) {
 	prm := PrmObjectCreate{
 		Container:    bktInfo.CID,
 		Locks:        []oid.ID{objID},
@@ -129,7 +129,7 @@ func (n *layer) putLockObject(ctx context.Context, bktInfo *data.BucketInfo, obj
 	return id, err
 }
 
-func (n *layer) GetLockInfo(ctx context.Context, objVersion *data.ObjectVersion) (*data.LockInfo, error) {
+func (n *Layer) GetLockInfo(ctx context.Context, objVersion *data.ObjectVersion) (*data.LockInfo, error) {
 	owner := n.BearerOwner(ctx)
 	if lockInfo := n.cache.GetLockInfo(owner, lockObjectKey(objVersion)); lockInfo != nil {
 		return lockInfo, nil
@@ -153,7 +153,7 @@ func (n *layer) GetLockInfo(ctx context.Context, objVersion *data.ObjectVersion)
 	return lockInfo, nil
 }
 
-func (n *layer) getCORS(ctx context.Context, bkt *data.BucketInfo) (*data.CORSConfiguration, error) {
+func (n *Layer) getCORS(ctx context.Context, bkt *data.BucketInfo) (*data.CORSConfiguration, error) {
 	owner := n.BearerOwner(ctx)
 	if cors := n.cache.GetCORS(owner, bkt); cors != nil {
 		return cors, nil
@@ -190,7 +190,7 @@ func lockObjectKey(objVersion *data.ObjectVersion) string {
 	return ".lock." + objVersion.BktInfo.CID.EncodeToString() + "." + objVersion.ObjectName + "." + objVersion.VersionID
 }
 
-func (n *layer) GetBucketSettings(ctx context.Context, bktInfo *data.BucketInfo) (*data.BucketSettings, error) {
+func (n *Layer) GetBucketSettings(ctx context.Context, bktInfo *data.BucketInfo) (*data.BucketSettings, error) {
 	owner := n.BearerOwner(ctx)
 	if settings := n.cache.GetSettings(owner, bktInfo); settings != nil {
 		return settings, nil
@@ -209,7 +209,7 @@ func (n *layer) GetBucketSettings(ctx context.Context, bktInfo *data.BucketInfo)
 	return settings, nil
 }
 
-func (n *layer) PutBucketSettings(ctx context.Context, p *PutSettingsParams) error {
+func (n *Layer) PutBucketSettings(ctx context.Context, p *PutSettingsParams) error {
 	if err := n.treeService.PutSettingsNode(ctx, p.BktInfo, p.Settings); err != nil {
 		return fmt.Errorf("failed to get settings node: %w", err)
 	}
@@ -219,7 +219,7 @@ func (n *layer) PutBucketSettings(ctx context.Context, p *PutSettingsParams) err
 	return nil
 }
 
-func (n *layer) attributesFromLock(ctx context.Context, lock *data.ObjectLock) ([][2]string, error) {
+func (n *Layer) attributesFromLock(ctx context.Context, lock *data.ObjectLock) ([][2]string, error) {
 	var (
 		err      error
 		expEpoch uint64
diff --git a/api/layer/tagging.go b/api/layer/tagging.go
index 7ef7b3d..293b6f6 100644
--- a/api/layer/tagging.go
+++ b/api/layer/tagging.go
@@ -14,7 +14,7 @@ import (
 	"go.uber.org/zap"
 )
 
-func (n *layer) GetObjectTagging(ctx context.Context, p *data.GetObjectTaggingParams) (string, map[string]string, error) {
+func (n *Layer) GetObjectTagging(ctx context.Context, p *data.GetObjectTaggingParams) (string, map[string]string, error) {
 	var err error
 	owner := n.BearerOwner(ctx)
 
@@ -50,7 +50,7 @@ func (n *layer) GetObjectTagging(ctx context.Context, p *data.GetObjectTaggingPa
 	return p.ObjectVersion.VersionID, tags, nil
 }
 
-func (n *layer) PutObjectTagging(ctx context.Context, p *data.PutObjectTaggingParams) (err error) {
+func (n *Layer) PutObjectTagging(ctx context.Context, p *data.PutObjectTaggingParams) (err error) {
 	nodeVersion := p.NodeVersion
 	if nodeVersion == nil {
 		nodeVersion, err = n.getNodeVersionFromCacheOrFrostfs(ctx, p.ObjectVersion)
@@ -73,7 +73,7 @@ func (n *layer) PutObjectTagging(ctx context.Context, p *data.PutObjectTaggingPa
 	return nil
 }
 
-func (n *layer) DeleteObjectTagging(ctx context.Context, p *data.ObjectVersion) error {
+func (n *Layer) DeleteObjectTagging(ctx context.Context, p *data.ObjectVersion) error {
 	version, err := n.getNodeVersion(ctx, p)
 	if err != nil {
 		return err
@@ -94,7 +94,7 @@ func (n *layer) DeleteObjectTagging(ctx context.Context, p *data.ObjectVersion)
 	return nil
 }
 
-func (n *layer) GetBucketTagging(ctx context.Context, bktInfo *data.BucketInfo) (map[string]string, error) {
+func (n *Layer) GetBucketTagging(ctx context.Context, bktInfo *data.BucketInfo) (map[string]string, error) {
 	owner := n.BearerOwner(ctx)
 
 	if tags := n.cache.GetTagging(owner, bucketTaggingCacheKey(bktInfo.CID)); tags != nil {
@@ -111,7 +111,7 @@ func (n *layer) GetBucketTagging(ctx context.Context, bktInfo *data.BucketInfo)
 	return tags, nil
 }
 
-func (n *layer) PutBucketTagging(ctx context.Context, bktInfo *data.BucketInfo, tagSet map[string]string) error {
+func (n *Layer) PutBucketTagging(ctx context.Context, bktInfo *data.BucketInfo, tagSet map[string]string) error {
 	if err := n.treeService.PutBucketTagging(ctx, bktInfo, tagSet); err != nil {
 		return err
 	}
@@ -121,7 +121,7 @@ func (n *layer) PutBucketTagging(ctx context.Context, bktInfo *data.BucketInfo,
 	return nil
 }
 
-func (n *layer) DeleteBucketTagging(ctx context.Context, bktInfo *data.BucketInfo) error {
+func (n *Layer) DeleteBucketTagging(ctx context.Context, bktInfo *data.BucketInfo) error {
 	n.cache.DeleteTagging(bucketTaggingCacheKey(bktInfo.CID))
 
 	return n.treeService.DeleteBucketTagging(ctx, bktInfo)
@@ -135,7 +135,7 @@ func bucketTaggingCacheKey(cnrID cid.ID) string {
 	return ".tagset." + cnrID.EncodeToString()
 }
 
-func (n *layer) getNodeVersion(ctx context.Context, objVersion *data.ObjectVersion) (*data.NodeVersion, error) {
+func (n *Layer) getNodeVersion(ctx context.Context, objVersion *data.ObjectVersion) (*data.NodeVersion, error) {
 	var err error
 	var version *data.NodeVersion
 
@@ -173,7 +173,7 @@ func (n *layer) getNodeVersion(ctx context.Context, objVersion *data.ObjectVersi
 	return version, err
 }
 
-func (n *layer) getNodeVersionFromCache(owner user.ID, o *data.ObjectVersion) *data.NodeVersion {
+func (n *Layer) getNodeVersionFromCache(owner user.ID, o *data.ObjectVersion) *data.NodeVersion {
 	if len(o.VersionID) == 0 || o.VersionID == data.UnversionedObjectVersionID {
 		return nil
 	}
diff --git a/api/layer/versioning_test.go b/api/layer/versioning_test.go
index 2c5ca5f..d037c03 100644
--- a/api/layer/versioning_test.go
+++ b/api/layer/versioning_test.go
@@ -130,7 +130,7 @@ func (tc *testContext) getObjectByID(objID oid.ID) *object.Object {
 type testContext struct {
 	t           *testing.T
 	ctx         context.Context
-	layer       Client
+	layer       *Layer
 	bktInfo     *data.BucketInfo
 	obj         string
 	testFrostFS *TestFrostFS
diff --git a/cmd/s3-gw/app.go b/cmd/s3-gw/app.go
index b022b50..3ccc425 100644
--- a/cmd/s3-gw/app.go
+++ b/cmd/s3-gw/app.go
@@ -61,7 +61,7 @@ type (
 		pool     *pool.Pool
 		treePool *treepool.Pool
 		key      *keys.PrivateKey
-		obj      layer.Client
+		obj      *layer.Layer
 		api      api.Handler
 
 		frostfsid *frostfsid.FrostFSID