diff --git a/cmd/bucket-metadata-sys.go b/cmd/bucket-metadata-sys.go
index c4f4345c9..56a471d03 100644
--- a/cmd/bucket-metadata-sys.go
+++ b/cmd/bucket-metadata-sys.go
@@ -81,7 +81,7 @@ func (sys *BucketMetadataSys) Update(bucket string, configFile string, configDat
 		// This code is needed only for gateway implementations.
 		switch configFile {
 		case bucketSSEConfig:
-			if globalGatewayName == "nas" {
+			if globalGatewayName == NASBackendGateway {
 				meta, err := loadBucketMetadata(GlobalContext, objAPI, bucket)
 				if err != nil {
 					return err
@@ -90,7 +90,7 @@ func (sys *BucketMetadataSys) Update(bucket string, configFile string, configDat
 				return meta.Save(GlobalContext, objAPI)
 			}
 		case bucketLifecycleConfig:
-			if globalGatewayName == "nas" {
+			if globalGatewayName == NASBackendGateway {
 				meta, err := loadBucketMetadata(GlobalContext, objAPI, bucket)
 				if err != nil {
 					return err
@@ -99,7 +99,7 @@ func (sys *BucketMetadataSys) Update(bucket string, configFile string, configDat
 				return meta.Save(GlobalContext, objAPI)
 			}
 		case bucketTaggingConfig:
-			if globalGatewayName == "nas" {
+			if globalGatewayName == NASBackendGateway {
 				meta, err := loadBucketMetadata(GlobalContext, objAPI, bucket)
 				if err != nil {
 					return err
@@ -108,7 +108,7 @@ func (sys *BucketMetadataSys) Update(bucket string, configFile string, configDat
 				return meta.Save(GlobalContext, objAPI)
 			}
 		case bucketNotificationConfig:
-			if globalGatewayName == "nas" {
+			if globalGatewayName == NASBackendGateway {
 				meta, err := loadBucketMetadata(GlobalContext, objAPI, bucket)
 				if err != nil {
 					return err
@@ -273,7 +273,7 @@ func (sys *BucketMetadataSys) GetLifecycleConfig(bucket string) (*lifecycle.Life
 // GetNotificationConfig returns configured notification config
 // The returned object may not be modified.
 func (sys *BucketMetadataSys) GetNotificationConfig(bucket string) (*event.Config, error) {
-	if globalIsGateway && globalGatewayName == "nas" {
+	if globalIsGateway && globalGatewayName == NASBackendGateway {
 		// Only needed in case of NAS gateway.
 		objAPI := newObjectLayerWithoutSafeModeFn()
 		if objAPI == nil {
diff --git a/cmd/gateway-interface.go b/cmd/gateway-interface.go
index 4b92dcc3c..21b81ff67 100644
--- a/cmd/gateway-interface.go
+++ b/cmd/gateway-interface.go
@@ -21,7 +21,14 @@ import (
 )
 
 // GatewayMinioSysTmp prefix is used in Azure/GCS gateway for save metadata sent by Initialize Multipart Upload API.
-const GatewayMinioSysTmp = "minio.sys.tmp/"
+const (
+	GatewayMinioSysTmp  = "minio.sys.tmp/"
+	AzureBackendGateway = "azure"
+	GCSBackendGateway   = "gcs"
+	HDFSBackendGateway  = "hdfs"
+	NASBackendGateway   = "nas"
+	S3BackendGateway    = "s3"
+)
 
 // Gateway represents a gateway backend.
 type Gateway interface {
diff --git a/cmd/gateway-main.go b/cmd/gateway-main.go
index fc42501d4..3c237ffcc 100644
--- a/cmd/gateway-main.go
+++ b/cmd/gateway-main.go
@@ -262,8 +262,8 @@ func StartGateway(ctx *cli.Context, gw Gateway) {
 	}
 
 	// Currently only NAS and S3 gateway support encryption headers.
-	encryptionEnabled := gatewayName == "s3" || gatewayName == "nas"
-	allowSSEKMS := gatewayName == "s3" // Only S3 can support SSE-KMS (as pass-through)
+	encryptionEnabled := gatewayName == S3BackendGateway || gatewayName == NASBackendGateway
+	allowSSEKMS := gatewayName == S3BackendGateway // Only S3 can support SSE-KMS (as pass-through)
 
 	// Add API router.
 	registerAPIRouter(router, encryptionEnabled, allowSSEKMS)
@@ -310,7 +310,7 @@ func StartGateway(ctx *cli.Context, gw Gateway) {
 	// Calls all New() for all sub-systems.
 	newAllSubsystems()
 
-	if gatewayName == "nas" {
+	if gatewayName == NASBackendGateway {
 		buckets, err := newObject.ListBuckets(GlobalContext)
 		if err != nil {
 			logger.Fatal(err, "Unable to list buckets")
diff --git a/cmd/gateway/azure/gateway-azure.go b/cmd/gateway/azure/gateway-azure.go
index ac64d0085..b47c9438a 100644
--- a/cmd/gateway/azure/gateway-azure.go
+++ b/cmd/gateway/azure/gateway-azure.go
@@ -73,7 +73,6 @@ const (
 	azureBlockSize             = 100 * humanize.MiByte
 	azureS3MinPartSize         = 5 * humanize.MiByte
 	metadataObjectNameTemplate = minio.GatewayMinioSysTmp + "multipart/v1/%s.%x/azure.json"
-	azureBackend               = "azure"
 	azureMarkerPrefix          = "{minio}"
 	metadataPartNamePrefix     = minio.GatewayMinioSysTmp + "multipart/v1/%s.%x"
 	maxPartsCount              = 10000
@@ -113,7 +112,7 @@ EXAMPLES:
 `
 
 	minio.RegisterGatewayCommand(cli.Command{
-		Name:               azureBackend,
+		Name:               minio.AzureBackendGateway,
 		Usage:              "Microsoft Azure Blob Storage",
 		Action:             azureGatewayMain,
 		CustomHelpTemplate: azureGatewayTemplate,
@@ -170,7 +169,7 @@ type Azure struct {
 
 // Name implements Gateway interface.
 func (g *Azure) Name() string {
-	return azureBackend
+	return minio.AzureBackendGateway
 }
 
 // NewGatewayLayer initializes azure blob storage client and returns AzureObjects.
diff --git a/cmd/gateway/gcs/gateway-gcs.go b/cmd/gateway/gcs/gateway-gcs.go
index 1bbb7a960..79d774557 100644
--- a/cmd/gateway/gcs/gateway-gcs.go
+++ b/cmd/gateway/gcs/gateway-gcs.go
@@ -91,8 +91,6 @@ const (
 
 	// Project ID key in credentials.json
 	gcsProjectIDKey = "project_id"
-
-	gcsBackend = "gcs"
 )
 
 func init() {
@@ -132,7 +130,7 @@ EXAMPLES:
 `
 
 	minio.RegisterGatewayCommand(cli.Command{
-		Name:               gcsBackend,
+		Name:               minio.GCSBackendGateway,
 		Usage:              "Google Cloud Storage",
 		Action:             gcsGatewayMain,
 		CustomHelpTemplate: gcsGatewayTemplate,
@@ -145,13 +143,13 @@ func gcsGatewayMain(ctx *cli.Context) {
 	projectID := ctx.Args().First()
 	if projectID == "" && os.Getenv("GOOGLE_APPLICATION_CREDENTIALS") == "" {
 		logger.LogIf(minio.GlobalContext, errGCSProjectIDNotFound, logger.Application)
-		cli.ShowCommandHelpAndExit(ctx, "gcs", 1)
+		cli.ShowCommandHelpAndExit(ctx, minio.GCSBackendGateway, 1)
 	}
 	if projectID != "" && !isValidGCSProjectIDFormat(projectID) {
 		reqInfo := (&logger.ReqInfo{}).AppendTags("projectID", ctx.Args().First())
 		contxt := logger.SetReqInfo(minio.GlobalContext, reqInfo)
 		logger.LogIf(contxt, errGCSInvalidProjectID, logger.Application)
-		cli.ShowCommandHelpAndExit(ctx, "gcs", 1)
+		cli.ShowCommandHelpAndExit(ctx, minio.GCSBackendGateway, 1)
 	}
 
 	minio.StartGateway(ctx, &GCS{projectID})
@@ -164,7 +162,7 @@ type GCS struct {
 
 // Name returns the name of gcs ObjectLayer.
 func (g *GCS) Name() string {
-	return gcsBackend
+	return minio.GCSBackendGateway
 }
 
 // NewGatewayLayer returns gcs ObjectLayer.
diff --git a/cmd/gateway/hdfs/gateway-hdfs.go b/cmd/gateway/hdfs/gateway-hdfs.go
index ec654d55c..6160dca0f 100644
--- a/cmd/gateway/hdfs/gateway-hdfs.go
+++ b/cmd/gateway/hdfs/gateway-hdfs.go
@@ -47,8 +47,6 @@ import (
 )
 
 const (
-	hdfsBackend = "hdfs"
-
 	hdfsSeparator = minio.SlashSeparator
 )
 
@@ -84,7 +82,7 @@ EXAMPLES:
 `
 
 	minio.RegisterGatewayCommand(cli.Command{
-		Name:               hdfsBackend,
+		Name:               minio.HDFSBackendGateway,
 		Usage:              "Hadoop Distributed File System (HDFS)",
 		Action:             hdfsGatewayMain,
 		CustomHelpTemplate: hdfsGatewayTemplate,
@@ -96,7 +94,7 @@ EXAMPLES:
 func hdfsGatewayMain(ctx *cli.Context) {
 	// Validate gateway arguments.
 	if ctx.Args().First() == "help" {
-		cli.ShowCommandHelpAndExit(ctx, hdfsBackend, 1)
+		cli.ShowCommandHelpAndExit(ctx, minio.HDFSBackendGateway, 1)
 	}
 
 	minio.StartGateway(ctx, &HDFS{args: ctx.Args()})
@@ -109,7 +107,7 @@ type HDFS struct {
 
 // Name implements Gateway interface.
 func (g *HDFS) Name() string {
-	return hdfsBackend
+	return minio.HDFSBackendGateway
 }
 
 func getKerberosClient() (*krb.Client, error) {
diff --git a/cmd/gateway/nas/gateway-nas.go b/cmd/gateway/nas/gateway-nas.go
index eca3949cd..42f5683b4 100644
--- a/cmd/gateway/nas/gateway-nas.go
+++ b/cmd/gateway/nas/gateway-nas.go
@@ -24,10 +24,6 @@ import (
 	"github.com/minio/minio/pkg/auth"
 )
 
-const (
-	nasBackend = "nas"
-)
-
 func init() {
 	const nasGatewayTemplate = `NAME:
   {{.HelpName}} - {{.Usage}}
@@ -61,7 +57,7 @@ EXAMPLES:
 `
 
 	minio.RegisterGatewayCommand(cli.Command{
-		Name:               nasBackend,
+		Name:               minio.NASBackendGateway,
 		Usage:              "Network-attached storage (NAS)",
 		Action:             nasGatewayMain,
 		CustomHelpTemplate: nasGatewayTemplate,
@@ -73,7 +69,7 @@ EXAMPLES:
 func nasGatewayMain(ctx *cli.Context) {
 	// Validate gateway arguments.
 	if !ctx.Args().Present() || ctx.Args().First() == "help" {
-		cli.ShowCommandHelpAndExit(ctx, nasBackend, 1)
+		cli.ShowCommandHelpAndExit(ctx, minio.NASBackendGateway, 1)
 	}
 
 	minio.StartGateway(ctx, &NAS{ctx.Args().First()})
@@ -86,7 +82,7 @@ type NAS struct {
 
 // Name implements Gateway interface.
 func (g *NAS) Name() string {
-	return nasBackend
+	return minio.NASBackendGateway
 }
 
 // NewGatewayLayer returns nas gatewaylayer.
diff --git a/cmd/gateway/s3/gateway-s3.go b/cmd/gateway/s3/gateway-s3.go
index 37db6e276..69681d946 100644
--- a/cmd/gateway/s3/gateway-s3.go
+++ b/cmd/gateway/s3/gateway-s3.go
@@ -40,10 +40,6 @@ import (
 	"github.com/minio/minio/pkg/bucket/policy"
 )
 
-const (
-	s3Backend = "s3"
-)
-
 func init() {
 	const s3GatewayTemplate = `NAME:
   {{.HelpName}} - {{.Usage}}
@@ -76,7 +72,7 @@ EXAMPLES:
 `
 
 	minio.RegisterGatewayCommand(cli.Command{
-		Name:               s3Backend,
+		Name:               minio.S3BackendGateway,
 		Usage:              "Amazon Simple Storage Service (S3)",
 		Action:             s3GatewayMain,
 		CustomHelpTemplate: s3GatewayTemplate,
@@ -109,7 +105,7 @@ type S3 struct {
 
 // Name implements Gateway interface.
 func (g *S3) Name() string {
-	return s3Backend
+	return minio.S3BackendGateway
 }
 
 const letterBytes = "abcdefghijklmnopqrstuvwxyz01234569"
diff --git a/cmd/metrics.go b/cmd/metrics.go
index ec8b3b179..46e08611a 100644
--- a/cmd/metrics.go
+++ b/cmd/metrics.go
@@ -157,7 +157,7 @@ func healingMetricsPrometheus(ch chan<- prometheus.Metric) {
 // collects gateway specific metrics for MinIO instance in Prometheus specific format
 // and sends to given channel
 func gatewayMetricsPrometheus(ch chan<- prometheus.Metric) {
-	if !globalIsGateway || (globalGatewayName != "s3" && globalGatewayName != "azure" && globalGatewayName != "gcs") {
+	if !globalIsGateway || (globalGatewayName != S3BackendGateway && globalGatewayName != AzureBackendGateway && globalGatewayName != GCSBackendGateway) {
 		return
 	}