diff --git a/api/service/manager.go b/api/service/manager.go
index baaaba29b..1bb53137b 100644
--- a/api/service/manager.go
+++ b/api/service/manager.go
@@ -21,6 +21,7 @@ const (
 	BlockProposal
 	NetworkInfo
 	Prometheus
+	Synchronize
 )
 
 func (t Type) String() string {
@@ -37,6 +38,8 @@ func (t Type) String() string {
 		return "NetworkInfo"
 	case Prometheus:
 		return "Prometheus"
+	case Synchronize:
+		return "Synchronize"
 	default:
 		return "Unknown"
 	}
@@ -82,6 +85,11 @@ func (m *Manager) GetServices() []Service {
 	return m.services
 }
 
+// GetService get the specified service
+func (m *Manager) GetService(t Type) Service {
+	return m.serviceMap[t]
+}
+
 // StartServices run all registered services. If one of the starting service returns
 // an error, closing all started services.
 func (m *Manager) StartServices() (err error) {
diff --git a/api/service/synchronize/service.go b/api/service/synchronize/service.go
new file mode 100644
index 000000000..92aac3206
--- /dev/null
+++ b/api/service/synchronize/service.go
@@ -0,0 +1,37 @@
+package synchronize
+
+import (
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/harmony-one/harmony/core"
+	"github.com/harmony-one/harmony/hmy/downloader"
+	"github.com/harmony-one/harmony/p2p"
+)
+
+// Service is simply a adapter of Downloaders, which support block synchronization
+type Service struct {
+	Downloaders *downloader.Downloaders
+}
+
+// NewService creates the a new downloader service
+func NewService(host p2p.Host, bcs []*core.BlockChain, config downloader.Config) *Service {
+	return &Service{
+		Downloaders: downloader.NewDownloaders(host, bcs, config),
+	}
+}
+
+// Start start the service
+func (s *Service) Start() error {
+	s.Downloaders.Start()
+	return nil
+}
+
+// Stop stop the service
+func (s *Service) Stop() error {
+	s.Downloaders.Close()
+	return nil
+}
+
+// APIs return all APIs of the service
+func (s *Service) APIs() []rpc.API {
+	return nil
+}
diff --git a/cmd/harmony/config.go b/cmd/harmony/config.go
index 5923f7197..f569e9ea1 100644
--- a/cmd/harmony/config.go
+++ b/cmd/harmony/config.go
@@ -28,6 +28,7 @@ type harmonyConfig struct {
 	TxPool     txPoolConfig
 	Pprof      pprofConfig
 	Log        logConfig
+	Sync       syncConfig
 	Sys        *sysConfig        `toml:",omitempty"`
 	Consensus  *consensusConfig  `toml:",omitempty"`
 	Devnet     *devnetConfig     `toml:",omitempty"`
@@ -152,6 +153,20 @@ type prometheusConfig struct {
 	Gateway    string
 }
 
+type syncConfig struct {
+	// TODO: Remove this bool after stream sync is fully up.
+	Downloader     bool // start the sync downloader client
+	LegacyServer   bool // provide the gRPC sync protocol server
+	LegacyClient   bool // aside from stream sync protocol, also run gRPC client to get blocks
+	Concurrency    int  // concurrency used for stream sync protocol
+	MinPeers       int  // minimum streams to start a sync task.
+	InitStreams    int  // minimum streams in bootstrap to start sync loop.
+	DiscSoftLowCap int  // when number of streams is below this value, spin discover during check
+	DiscHardLowCap int  // when removing stream, num is below this value, spin discovery immediately
+	DiscHighCap    int  // upper limit of streams in one sync protocol
+	DiscBatch      int  // size of each discovery
+}
+
 // TODO: use specific type wise validation instead of general string types assertion.
 func validateHarmonyConfig(config harmonyConfig) error {
 	var accepts []string
@@ -188,6 +203,11 @@ func validateHarmonyConfig(config harmonyConfig) error {
 		return fmt.Errorf("flag --run.offline must have p2p IP be %v", nodeconfig.DefaultLocalListenIP)
 	}
 
+	if !config.Sync.Downloader && !config.Sync.LegacyClient {
+		// There is no module up for sync
+		return errors.New("either --sync.downloader or --sync.legacy.client shall be enabled")
+	}
+
 	return nil
 }
 
@@ -235,6 +255,17 @@ func parseNetworkType(nt string) nodeconfig.NetworkType {
 	}
 }
 
+func getDefaultSyncConfig(nt nodeconfig.NetworkType) syncConfig {
+	switch nt {
+	case nodeconfig.Mainnet:
+		return defaultMainnetSyncConfig
+	case nodeconfig.Testnet:
+		return defaultTestNetSyncConfig
+	default:
+		return defaultElseSyncConfig
+	}
+}
+
 var dumpConfigCmd = &cobra.Command{
 	Use:   "dumpconfig [config_file]",
 	Short: "dump the config file for harmony binary configurations",
diff --git a/cmd/harmony/config_test.go b/cmd/harmony/config_test.go
index 75aa71ef5..b0aecc939 100644
--- a/cmd/harmony/config_test.go
+++ b/cmd/harmony/config_test.go
@@ -30,7 +30,7 @@ func init() {
 }
 
 func TestV1_0_0Config(t *testing.T) {
-	testConfig := `Version = "1.0.3"
+	testConfig := `Version = "1.0.4"
 
 [BLSKeys]
   KMSConfigFile = ""
@@ -80,6 +80,18 @@ func TestV1_0_0Config(t *testing.T) {
 [TxPool]
   BlacklistFile = "./.hmy/blacklist.txt"
 
+[Sync]
+  Downloader = false
+  Concurrency = 6
+  DiscBatch = 8
+  DiscHardLowCap = 6
+  DiscHighCap = 128
+  DiscSoftLowCap = 8
+  InitStreams = 8
+  LegacyClient = true
+  LegacyServer = true
+  MinPeers = 6
+
 [WS]
   Enabled = true
   IP = "127.0.0.1"
@@ -96,20 +108,21 @@ func TestV1_0_0Config(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	defConf := getDefaultHmyConfigCopy(nodeconfig.Mainnet)
 	if config.HTTP.RosettaEnabled {
 		t.Errorf("Expected rosetta http server to be disabled when loading old config")
 	}
 	if config.General.IsOffline {
 		t.Errorf("Expect node to de online when loading old config")
 	}
-	if config.P2P.IP != defaultConfig.P2P.IP {
+	if config.P2P.IP != defConf.P2P.IP {
 		t.Errorf("Expect default p2p IP if old config is provided")
 	}
-	if config.Version != "1.0.3" {
-		t.Errorf("Expected config version: 1.0.3, not %v", config.Version)
+	if config.Version != "1.0.4" {
+		t.Errorf("Expected config version: 1.0.4, not %v", config.Version)
 	}
-	config.Version = defaultConfig.Version // Shortcut for testing, value checked above
-	if !reflect.DeepEqual(config, defaultConfig) {
+	config.Version = defConf.Version // Shortcut for testing, value checked above
+	if !reflect.DeepEqual(config, defConf) {
 		t.Errorf("Unexpected config \n\t%+v \n\t%+v", config, defaultConfig)
 	}
 }
diff --git a/cmd/harmony/default.go b/cmd/harmony/default.go
index 4c04b826f..a6be5c8d1 100644
--- a/cmd/harmony/default.go
+++ b/cmd/harmony/default.go
@@ -2,7 +2,7 @@ package main
 
 import nodeconfig "github.com/harmony-one/harmony/internal/configs/node"
 
-const tomlConfigVersion = "1.0.3"
+const tomlConfigVersion = "1.0.4"
 
 const (
 	defNetworkType = nodeconfig.Mainnet
@@ -102,6 +102,47 @@ var defaultPrometheusConfig = prometheusConfig{
 	Gateway:    "https://gateway.harmony.one",
 }
 
+var (
+	defaultMainnetSyncConfig = syncConfig{
+		Downloader:     false,
+		LegacyServer:   true,
+		LegacyClient:   true,
+		Concurrency:    6,
+		MinPeers:       6,
+		InitStreams:    8,
+		DiscSoftLowCap: 8,
+		DiscHardLowCap: 6,
+		DiscHighCap:    128,
+		DiscBatch:      8,
+	}
+
+	defaultTestNetSyncConfig = syncConfig{
+		Downloader:     false,
+		LegacyServer:   true,
+		LegacyClient:   true,
+		Concurrency:    4,
+		MinPeers:       4,
+		InitStreams:    4,
+		DiscSoftLowCap: 4,
+		DiscHardLowCap: 4,
+		DiscHighCap:    1024,
+		DiscBatch:      8,
+	}
+
+	defaultElseSyncConfig = syncConfig{
+		Downloader:     true,
+		LegacyServer:   true,
+		LegacyClient:   false,
+		Concurrency:    4,
+		MinPeers:       4,
+		InitStreams:    4,
+		DiscSoftLowCap: 4,
+		DiscHardLowCap: 4,
+		DiscHighCap:    1024,
+		DiscBatch:      8,
+	}
+)
+
 const (
 	defaultBroadcastInvalidTx = true
 )
@@ -114,6 +155,8 @@ func getDefaultHmyConfigCopy(nt nodeconfig.NetworkType) harmonyConfig {
 		devnet := getDefaultDevnetConfigCopy()
 		config.Devnet = &devnet
 	}
+	config.Sync = getDefaultSyncConfig(nt)
+
 	return config
 }
 
diff --git a/cmd/harmony/flags.go b/cmd/harmony/flags.go
index 5be21de29..34ffd516a 100644
--- a/cmd/harmony/flags.go
+++ b/cmd/harmony/flags.go
@@ -175,6 +175,19 @@ var (
 		prometheusGatewayFlag,
 		prometheusEnablePushFlag,
 	}
+
+	syncFlags = []cli.Flag{
+		syncDownloaderFlag,
+		syncLegacyClientFlag,
+		syncLegacyServerFlag,
+		syncConcurrencyFlag,
+		syncMinPeersFlag,
+		syncInitStreamsFlag,
+		syncDiscSoftLowFlag,
+		syncDiscHardLowFlag,
+		syncDiscHighFlag,
+		syncDiscBatchFlag,
+	}
 )
 
 var (
@@ -267,6 +280,7 @@ func getRootFlags() []cli.Flag {
 	flags = append(flags, revertFlags...)
 	flags = append(flags, legacyMiscFlags...)
 	flags = append(flags, prometheusFlags...)
+	flags = append(flags, syncFlags...)
 
 	return flags
 }
@@ -1269,3 +1283,108 @@ func applyPrometheusFlags(cmd *cobra.Command, config *harmonyConfig) {
 		config.Prometheus.EnablePush = cli.GetBoolFlagValue(cmd, prometheusEnablePushFlag)
 	}
 }
+
+var (
+	// TODO: Deprecate this flag, and always set to true after stream sync is fully up.
+	syncDownloaderFlag = cli.BoolFlag{
+		Name:     "sync.downloader",
+		Usage:    "Enable the downloader module to sync through stream sync protocol",
+		Hidden:   true,
+		DefValue: false,
+	}
+	syncLegacyServerFlag = cli.BoolFlag{
+		Name:     "sync.legacy.server",
+		Usage:    "Enable the gRPC sync server for backward compatibility",
+		Hidden:   true,
+		DefValue: true,
+	}
+	syncLegacyClientFlag = cli.BoolFlag{
+		Name:     "sync.legacy.client",
+		Usage:    "Enable the legacy centralized sync service for block synchronization",
+		Hidden:   true,
+		DefValue: false,
+	}
+	syncConcurrencyFlag = cli.IntFlag{
+		Name:   "sync.concurrency",
+		Usage:  "Concurrency when doing p2p sync requests",
+		Hidden: true,
+	}
+	syncMinPeersFlag = cli.IntFlag{
+		Name:   "sync.min-peers",
+		Usage:  "Minimum peers check for each shard-wise sync loop",
+		Hidden: true,
+	}
+	syncInitStreamsFlag = cli.IntFlag{
+		Name:   "sync.init-peers",
+		Usage:  "Initial shard-wise number of peers to start syncing",
+		Hidden: true,
+	}
+	syncDiscSoftLowFlag = cli.IntFlag{
+		Name:   "sync.disc.soft-low-cap",
+		Usage:  "Soft low cap for sync stream management",
+		Hidden: true,
+	}
+	syncDiscHardLowFlag = cli.IntFlag{
+		Name:   "sync.disc.hard-low-cap",
+		Usage:  "Hard low cap for sync stream management",
+		Hidden: true,
+	}
+	syncDiscHighFlag = cli.IntFlag{
+		Name:   "sync.disc.hi-cap",
+		Usage:  "High cap for sync stream management",
+		Hidden: true,
+	}
+	syncDiscBatchFlag = cli.IntFlag{
+		Name:   "sync.disc.batch",
+		Usage:  "batch size of the sync discovery",
+		Hidden: true,
+	}
+)
+
+// applySyncFlags apply the sync flags.
+func applySyncFlags(cmd *cobra.Command, config *harmonyConfig) {
+	if config.Sync == (syncConfig{}) {
+		nt := nodeconfig.NetworkType(config.Network.NetworkType)
+		config.Sync = getDefaultSyncConfig(nt)
+	}
+
+	if cli.IsFlagChanged(cmd, syncDownloaderFlag) {
+		config.Sync.Downloader = cli.GetBoolFlagValue(cmd, syncDownloaderFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncLegacyServerFlag) {
+		config.Sync.LegacyServer = cli.GetBoolFlagValue(cmd, syncLegacyServerFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncLegacyClientFlag) {
+		config.Sync.LegacyClient = cli.GetBoolFlagValue(cmd, syncLegacyClientFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncConcurrencyFlag) {
+		config.Sync.Concurrency = cli.GetIntFlagValue(cmd, syncConcurrencyFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncMinPeersFlag) {
+		config.Sync.MinPeers = cli.GetIntFlagValue(cmd, syncMinPeersFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncInitStreamsFlag) {
+		config.Sync.InitStreams = cli.GetIntFlagValue(cmd, syncInitStreamsFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncDiscSoftLowFlag) {
+		config.Sync.DiscSoftLowCap = cli.GetIntFlagValue(cmd, syncDiscSoftLowFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncDiscHardLowFlag) {
+		config.Sync.DiscHardLowCap = cli.GetIntFlagValue(cmd, syncDiscHardLowFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncDiscHighFlag) {
+		config.Sync.DiscHighCap = cli.GetIntFlagValue(cmd, syncDiscHighFlag)
+	}
+
+	if cli.IsFlagChanged(cmd, syncDiscBatchFlag) {
+		config.Sync.DiscBatch = cli.GetIntFlagValue(cmd, syncDiscBatchFlag)
+	}
+}
diff --git a/cmd/harmony/flags_test.go b/cmd/harmony/flags_test.go
index 2f9d0ddf0..2f2738057 100644
--- a/cmd/harmony/flags_test.go
+++ b/cmd/harmony/flags_test.go
@@ -112,6 +112,7 @@ func TestHarmonyFlags(t *testing.T) {
 					EnablePush: true,
 					Gateway:    "https://gateway.harmony.one",
 				},
+				Sync: defaultMainnetSyncConfig,
 			},
 		},
 	}
@@ -947,6 +948,79 @@ func TestRevertFlags(t *testing.T) {
 	}
 }
 
+func TestSyncFlags(t *testing.T) {
+	tests := []struct {
+		args      []string
+		network   string
+		expConfig syncConfig
+		expErr    error
+	}{
+		{
+			args:      []string{},
+			network:   "mainnet",
+			expConfig: defaultMainnetSyncConfig,
+		},
+		{
+			args:    []string{"--sync.legacy.server", "--sync.legacy.client"},
+			network: "mainnet",
+			expConfig: func() syncConfig {
+				cfg := defaultMainnetSyncConfig
+				cfg.LegacyClient = true
+				cfg.LegacyServer = true
+				return cfg
+			}(),
+		},
+		{
+			args:    []string{"--sync.legacy.server", "--sync.legacy.client"},
+			network: "testnet",
+			expConfig: func() syncConfig {
+				cfg := defaultTestNetSyncConfig
+				cfg.LegacyClient = true
+				cfg.LegacyServer = true
+				return cfg
+			}(),
+		},
+		{
+			args: []string{"--sync.downloader", "--sync.concurrency", "10", "--sync.min-peers", "10",
+				"--sync.init-peers", "10", "--sync.disc.soft-low-cap", "10",
+				"--sync.disc.hard-low-cap", "10", "--sync.disc.hi-cap", "10",
+				"--sync.disc.batch", "10",
+			},
+			network: "mainnet",
+			expConfig: func() syncConfig {
+				cfg := defaultMainnetSyncConfig
+				cfg.Downloader = true
+				cfg.Concurrency = 10
+				cfg.MinPeers = 10
+				cfg.InitStreams = 10
+				cfg.DiscSoftLowCap = 10
+				cfg.DiscHardLowCap = 10
+				cfg.DiscHighCap = 10
+				cfg.DiscBatch = 10
+				return cfg
+			}(),
+		},
+	}
+	for i, test := range tests {
+		ts := newFlagTestSuite(t, syncFlags, func(command *cobra.Command, config *harmonyConfig) {
+			config.Network.NetworkType = test.network
+			applySyncFlags(command, config)
+		})
+		hc, err := ts.run(test.args)
+
+		if assErr := assertError(err, test.expErr); assErr != nil {
+			t.Fatalf("Test %v: %v", i, assErr)
+		}
+		if err != nil || test.expErr != nil {
+			continue
+		}
+		if !reflect.DeepEqual(hc.Sync, test.expConfig) {
+			t.Errorf("Test %v:\n\t%+v\n\t%+v", i, hc.Sync, test.expConfig)
+		}
+		ts.tearDown()
+	}
+}
+
 type flagTestSuite struct {
 	t *testing.T
 
diff --git a/cmd/harmony/main.go b/cmd/harmony/main.go
index c6905d351..388aa8fed 100644
--- a/cmd/harmony/main.go
+++ b/cmd/harmony/main.go
@@ -16,6 +16,9 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/harmony-one/harmony/api/service/synchronize"
+	"github.com/harmony-one/harmony/hmy/downloader"
+
 	ethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/harmony-one/bls/ffi/go/bls"
@@ -204,6 +207,7 @@ func applyRootFlags(cmd *cobra.Command, config *harmonyConfig) {
 	applyDevnetFlags(cmd, config)
 	applyRevertFlags(cmd, config)
 	applyPrometheusFlags(cmd, config)
+	applySyncFlags(cmd, config)
 }
 
 func setupNodeLog(config harmonyConfig) {
@@ -278,6 +282,7 @@ func setupNodeAndRun(hc harmonyConfig) {
 	currentNode := setupConsensusAndNode(hc, nodeConfig)
 	nodeconfig.GetDefaultConfig().ShardID = nodeConfig.ShardID
 	nodeconfig.GetDefaultConfig().IsOffline = nodeConfig.IsOffline
+	nodeconfig.GetDefaultConfig().Downloader = nodeConfig.Downloader
 
 	// Check NTP configuration
 	accurate, err := ntp.CheckLocalTimeAccurate(nodeConfig.NtpServer)
@@ -304,12 +309,6 @@ func setupNodeAndRun(hc harmonyConfig) {
 		WSPort:       hc.WS.Port,
 		DebugEnabled: hc.RPCOpt.DebugEnabled,
 	}
-	if nodeConfig.ShardID != shard.BeaconChainShardID {
-		utils.Logger().Info().
-			Uint32("shardID", currentNode.Blockchain().ShardID()).
-			Uint32("shardID", nodeConfig.ShardID).Msg("SupportBeaconSyncing")
-		currentNode.SupportBeaconSyncing()
-	}
 
 	// Parse rosetta config
 	nodeConfig.RosettaServer = nodeconfig.RosettaServerConfig{
@@ -360,6 +359,9 @@ func setupNodeAndRun(hc harmonyConfig) {
 
 	nodeconfig.SetPeerID(myHost.GetID())
 
+	// Setup services
+	setupSyncService(currentNode, myHost, hc)
+
 	if currentNode.NodeConfig.Role() == nodeconfig.Validator {
 		currentNode.RegisterValidatorServices()
 	} else if currentNode.NodeConfig.Role() == nodeconfig.ExplorerNode {
@@ -369,8 +371,14 @@ func setupNodeAndRun(hc harmonyConfig) {
 		setupPrometheusService(currentNode, hc, nodeConfig.ShardID)
 	}
 
-	// TODO: replace this legacy syncing
-	currentNode.SupportSyncing()
+	if hc.Sync.LegacyServer && !hc.General.IsOffline {
+		utils.Logger().Info().Msg("support gRPC sync server")
+		currentNode.SupportGRPCSyncServer()
+	}
+	if hc.Sync.LegacyClient && !hc.General.IsOffline {
+		utils.Logger().Info().Msg("go with gRPC sync client")
+		currentNode.StartGRPCSyncClient()
+	}
 
 	if err := currentNode.StartServices(); err != nil {
 		fmt.Fprint(os.Stderr, err.Error())
@@ -391,22 +399,24 @@ func setupNodeAndRun(hc harmonyConfig) {
 
 	go listenOSSigAndShutDown(currentNode)
 
-	if err := myHost.Start(); err != nil {
-		utils.Logger().Fatal().
-			Err(err).
-			Msg("Start p2p host failed")
-	}
+	if !hc.General.IsOffline {
+		if err := myHost.Start(); err != nil {
+			utils.Logger().Fatal().
+				Err(err).
+				Msg("Start p2p host failed")
+		}
 
-	if err := currentNode.BootstrapConsensus(); err != nil {
-		fmt.Fprint(os.Stderr, "could not bootstrap consensus", err.Error())
-		if !currentNode.NodeConfig.IsOffline {
-			os.Exit(-1)
+		if err := currentNode.BootstrapConsensus(); err != nil {
+			fmt.Fprint(os.Stderr, "could not bootstrap consensus", err.Error())
+			if !currentNode.NodeConfig.IsOffline {
+				os.Exit(-1)
+			}
 		}
-	}
 
-	if err := currentNode.StartPubSub(); err != nil {
-		fmt.Fprint(os.Stderr, "could not begin network message handling for node", err.Error())
-		os.Exit(-1)
+		if err := currentNode.StartPubSub(); err != nil {
+			fmt.Fprint(os.Stderr, "could not begin network message handling for node", err.Error())
+			os.Exit(-1)
+		}
 	}
 
 	select {}
@@ -529,6 +539,7 @@ func createGlobalConfig(hc harmonyConfig) (*nodeconfig.ConfigType, error) {
 	nodeConfig.SetShardID(initialAccounts[0].ShardID) // sets shard ID
 	nodeConfig.SetArchival(hc.General.IsBeaconArchival, hc.General.IsArchival)
 	nodeConfig.IsOffline = hc.General.IsOffline
+	nodeConfig.Downloader = hc.Sync.Downloader
 
 	// P2P private key is used for secure message transfer between p2p nodes.
 	nodeConfig.P2PPriKey, _, err = utils.LoadKeyFromFile(hc.P2P.KeyFile)
@@ -699,6 +710,39 @@ func setupPrometheusService(node *node.Node, hc harmonyConfig, sid uint32) {
 	node.RegisterService(service.Prometheus, p)
 }
 
+func setupSyncService(node *node.Node, host p2p.Host, hc harmonyConfig) {
+	blockchains := []*core.BlockChain{node.Blockchain()}
+	if !node.IsRunningBeaconChain() {
+		blockchains = append(blockchains, node.Beaconchain())
+	}
+
+	dConfig := downloader.Config{
+		ServerOnly:   !hc.Sync.Downloader,
+		Network:      nodeconfig.NetworkType(hc.Network.NetworkType),
+		Concurrency:  hc.Sync.Concurrency,
+		MinStreams:   hc.Sync.MinPeers,
+		InitStreams:  hc.Sync.InitStreams,
+		SmSoftLowCap: hc.Sync.DiscSoftLowCap,
+		SmHardLowCap: hc.Sync.DiscHardLowCap,
+		SmHiCap:      hc.Sync.DiscHighCap,
+		SmDiscBatch:  hc.Sync.DiscBatch,
+	}
+	// If we are running side chain, we will need to do some extra works for beacon
+	// sync
+	if !node.IsRunningBeaconChain() {
+		dConfig.BHConfig = &downloader.BeaconHelperConfig{
+			BlockC:     node.BeaconBlockChannel,
+			InsertHook: node.BeaconSyncHook,
+		}
+	}
+	s := synchronize.NewService(host, blockchains, dConfig)
+
+	node.RegisterService(service.Synchronize, s)
+
+	d := s.Downloaders.GetShardDownloader(node.Blockchain().ShardID())
+	node.Consensus.SetDownloader(d)
+}
+
 func setupBlacklist(hc harmonyConfig) (map[ethCommon.Address]struct{}, error) {
 	utils.Logger().Debug().Msgf("Using blacklist file at `%s`", hc.TxPool.BlacklistFile)
 	dat, err := ioutil.ReadFile(hc.TxPool.BlacklistFile)
diff --git a/hmy/downloader/beaconhelper.go b/hmy/downloader/beaconhelper.go
index 4b0e643e6..9d689534c 100644
--- a/hmy/downloader/beaconhelper.go
+++ b/hmy/downloader/beaconhelper.go
@@ -120,7 +120,9 @@ func (bh *beaconHelper) insertLastMileBlocks() (inserted int, bn uint64, err err
 			bn--
 			return
 		}
-		if err = bh.ih.verifyAndInsertBlock(b); err != nil {
+		// TODO: Instruct the beacon helper to verify signatures. This may require some forks
+		//       in pub-sub message (add commit sigs in node.block.sync messages)
+		if _, err = bh.bc.InsertChain(types.Blocks{b}, true); err != nil {
 			bn--
 			return
 		}
diff --git a/hmy/downloader/const.go b/hmy/downloader/const.go
index c7246c64c..06da5c742 100644
--- a/hmy/downloader/const.go
+++ b/hmy/downloader/const.go
@@ -25,6 +25,10 @@ const (
 type (
 	// Config is the downloader config
 	Config struct {
+		// Only run stream sync protocol as a server.
+		// TODO: remove this when stream sync is fully up.
+		ServerOnly bool
+
 		// parameters
 		Network     nodeconfig.NetworkType
 		Concurrency int // Number of concurrent sync requests
diff --git a/hmy/downloader/downloader.go b/hmy/downloader/downloader.go
index a4e8d23f3..de967a61a 100644
--- a/hmy/downloader/downloader.go
+++ b/hmy/downloader/downloader.go
@@ -82,6 +82,10 @@ func NewDownloader(host p2p.Host, bc *core.BlockChain, config Config) *Downloade
 
 // Start start the downloader
 func (d *Downloader) Start() {
+	if d.config.ServerOnly {
+		return
+	}
+
 	go d.run()
 
 	if d.bh != nil {
@@ -91,6 +95,10 @@ func (d *Downloader) Start() {
 
 // Close close the downloader
 func (d *Downloader) Close() {
+	if d.config.ServerOnly {
+		return
+	}
+
 	close(d.closeC)
 	d.cancel()
 
diff --git a/hmy/downloader/shortrange.go b/hmy/downloader/shortrange.go
index 2c0e52e8c..f898f20fd 100644
--- a/hmy/downloader/shortrange.go
+++ b/hmy/downloader/shortrange.go
@@ -15,6 +15,8 @@ import (
 	"github.com/rs/zerolog"
 )
 
+var emptySigVerifyError *sigVerifyError
+
 // doShortRangeSync does the short range sync.
 // Compared with long range sync, short range sync is more focused on syncing to the latest block.
 // It consist of 3 steps:
@@ -56,7 +58,7 @@ func (d *Downloader) doShortRangeSync() (int, error) {
 	}
 	n, err := d.ih.verifyAndInsertBlocks(blocks)
 	if err != nil {
-		if !errors.As(err, &sigVerifyError{}) {
+		if !errors.As(err, &emptySigVerifyError) {
 			sh.removeStreams(whitelist) // Data provided by remote nodes is corrupted
 		}
 		return n, errors.Wrap(err, "InsertChain")
diff --git a/hmy/hmy.go b/hmy/hmy.go
index 8962c51b5..d2f4c992b 100644
--- a/hmy/hmy.go
+++ b/hmy/hmy.go
@@ -87,8 +87,9 @@ type NodeAPI interface {
 	GetTransactionsCount(address, txType string) (uint64, error)
 	GetStakingTransactionsCount(address, txType string) (uint64, error)
 	IsCurrentlyLeader() bool
-	IsOutOfSync(*core.BlockChain) bool
-	GetMaxPeerHeight() uint64
+	IsOutOfSync(shardID uint32) bool
+	SyncStatus(shardID uint32) (bool, uint64)
+	SyncPeers() map[string]int
 	ReportStakingErrorSink() types.TransactionErrorReports
 	ReportPlainErrorSink() types.TransactionErrorReports
 	PendingCXReceipts() []*types.CXReceiptsProof
@@ -186,6 +187,7 @@ func (hmy *Harmony) GetNodeMetadata() commonRPC.NodeMetadata {
 	c := commonRPC.C{}
 	c.TotalKnownPeers, c.Connected, c.NotConnected = hmy.NodeAPI.PeerConnectivity()
 
+	syncPeers := hmy.NodeAPI.SyncPeers()
 	consensusInternal := hmy.NodeAPI.GetConsensusInternal()
 
 	return commonRPC.NodeMetadata{
@@ -204,6 +206,7 @@ func (hmy *Harmony) GetNodeMetadata() commonRPC.NodeMetadata {
 		PeerID:         nodeconfig.GetPeerID(),
 		Consensus:      consensusInternal,
 		C:              c,
+		SyncPeers:      syncPeers,
 	}
 }
 
diff --git a/internal/configs/node/config.go b/internal/configs/node/config.go
index bebc515b6..4897c6e43 100644
--- a/internal/configs/node/config.go
+++ b/internal/configs/node/config.go
@@ -80,6 +80,7 @@ type ConfigType struct {
 	RPCServer       RPCServerConfig     // RPC server port and ip
 	RosettaServer   RosettaServerConfig // rosetta server port and ip
 	IsOffline       bool
+	Downloader      bool // Whether stream downloader is running; TODO: remove this after sync up
 	NtpServer       string
 	StringRole      string
 	P2PPriKey       p2p_crypto.PrivKey
diff --git a/node/double_signing.go b/node/double_signing.go
index a8c40eda8..dd9787941 100644
--- a/node/double_signing.go
+++ b/node/double_signing.go
@@ -3,13 +3,12 @@ package node
 import (
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/harmony-one/harmony/internal/utils"
-	"github.com/harmony-one/harmony/shard"
 	"github.com/harmony-one/harmony/staking/slash"
 )
 
 // ProcessSlashCandidateMessage ..
 func (node *Node) processSlashCandidateMessage(msgPayload []byte) {
-	if node.NodeConfig.ShardID != shard.BeaconChainShardID {
+	if !node.IsRunningBeaconChain() {
 		return
 	}
 	candidates := slash.Records{}
diff --git a/node/node.go b/node/node.go
index bb479ebf4..2de5dc463 100644
--- a/node/node.go
+++ b/node/node.go
@@ -217,7 +217,7 @@ func (node *Node) addPendingTransactions(newTxs types.Transactions) []error {
 
 // Add new staking transactions to the pending staking transaction list.
 func (node *Node) addPendingStakingTransactions(newStakingTxs staking.StakingTransactions) []error {
-	if node.NodeConfig.ShardID == shard.BeaconChainShardID {
+	if node.IsRunningBeaconChain() {
 		if node.Blockchain().Config().IsPreStaking(node.Blockchain().CurrentHeader().Epoch()) {
 			poolTxs := types.PoolTransactions{}
 			for _, tx := range newStakingTxs {
@@ -245,7 +245,7 @@ func (node *Node) addPendingStakingTransactions(newStakingTxs staking.StakingTra
 func (node *Node) AddPendingStakingTransaction(
 	newStakingTx *staking.StakingTransaction,
 ) error {
-	if node.NodeConfig.ShardID == shard.BeaconChainShardID {
+	if node.IsRunningBeaconChain() {
 		errs := node.addPendingStakingTransactions(staking.StakingTransactions{newStakingTx})
 		var err error
 		for i := range errs {
@@ -404,7 +404,7 @@ func (node *Node) validateNodeMessage(ctx context.Context, payload []byte) (
 		case proto_node.SlashCandidate:
 			nodeNodeMessageCounterVec.With(prometheus.Labels{"type": "slash"}).Inc()
 			// only beacon chain node process slash candidate messages
-			if node.NodeConfig.ShardID != shard.BeaconChainShardID {
+			if !node.IsRunningBeaconChain() {
 				return nil, 0, errIgnoreBeaconMsg
 			}
 		case proto_node.Receipt:
@@ -412,7 +412,7 @@ func (node *Node) validateNodeMessage(ctx context.Context, payload []byte) (
 		case proto_node.CrossLink:
 			nodeNodeMessageCounterVec.With(prometheus.Labels{"type": "crosslink"}).Inc()
 			// only beacon chain node process crosslink messages
-			if node.NodeConfig.ShardID != shard.BeaconChainShardID ||
+			if !node.IsRunningBeaconChain() ||
 				node.NodeConfig.Role() == nodeconfig.ExplorerNode {
 				return nil, 0, errIgnoreBeaconMsg
 			}
@@ -1016,7 +1016,7 @@ func New(
 						go func() { webhooks.DoPost(url, &doubleSign) }()
 					}
 				}
-				if node.NodeConfig.ShardID != shard.BeaconChainShardID {
+				if !node.IsRunningBeaconChain() {
 					go node.BroadcastSlash(&doubleSign)
 				} else {
 					records := slash.Records{doubleSign}
@@ -1282,3 +1282,8 @@ func (node *Node) GetAddresses(epoch *big.Int) map[string]common.Address {
 	// self addresses map can never be nil
 	return node.KeysToAddrs
 }
+
+// IsRunningBeaconChain returns whether the node is running on beacon chain.
+func (node *Node) IsRunningBeaconChain() bool {
+	return node.NodeConfig.ShardID == shard.BeaconChainShardID
+}
diff --git a/node/node_cross_link.go b/node/node_cross_link.go
index f951807ce..0d52ccd46 100644
--- a/node/node_cross_link.go
+++ b/node/node_cross_link.go
@@ -61,7 +61,7 @@ func (node *Node) VerifyBlockCrossLinks(block *types.Block) error {
 
 // ProcessCrossLinkMessage verify and process Node/CrossLink message into crosslink when it's valid
 func (node *Node) ProcessCrossLinkMessage(msgPayload []byte) {
-	if node.NodeConfig.ShardID == shard.BeaconChainShardID {
+	if node.IsRunningBeaconChain() {
 		pendingCLs, err := node.Blockchain().ReadPendingCrossLinks()
 		if err == nil && len(pendingCLs) >= maxPendingCrossLinkSize {
 			utils.Logger().Debug().
diff --git a/node/node_handler.go b/node/node_handler.go
index 8a86a8fa9..3e02a6b94 100644
--- a/node/node_handler.go
+++ b/node/node_handler.go
@@ -171,7 +171,7 @@ func (node *Node) BroadcastCrossLink() {
 		return
 	}
 
-	if node.NodeConfig.ShardID == shard.BeaconChainShardID ||
+	if node.IsRunningBeaconChain() ||
 		!node.Blockchain().Config().IsCrossLink(curBlock.Epoch()) {
 		// no need to broadcast crosslink if it's beacon chain or it's not crosslink epoch
 		return
@@ -308,7 +308,7 @@ func (node *Node) VerifyNewBlock(newBlock *types.Block) error {
 
 	// Verify cross links
 	// TODO: move into ValidateNewBlock
-	if node.NodeConfig.ShardID == shard.BeaconChainShardID {
+	if node.IsRunningBeaconChain() {
 		err := node.VerifyBlockCrossLinks(newBlock)
 		if err != nil {
 			utils.Logger().Debug().Err(err).Msg("ops2 VerifyBlockCrossLinks Failed")
@@ -336,7 +336,7 @@ func (node *Node) VerifyNewBlock(newBlock *types.Block) error {
 // 3. [leader] send cross shard tx receipts to destination shard
 func (node *Node) PostConsensusProcessing(newBlock *types.Block) error {
 	if node.Consensus.IsLeader() {
-		if node.NodeConfig.ShardID == shard.BeaconChainShardID {
+		if node.IsRunningBeaconChain() {
 			node.BroadcastNewBlock(newBlock)
 		}
 		node.BroadcastCXReceipts(newBlock)
@@ -360,7 +360,7 @@ func (node *Node) PostConsensusProcessing(newBlock *types.Block) error {
 			rnd := rand.Intn(100)
 			if rnd < 1 {
 				// Beacon validators also broadcast new blocks to make sure beacon sync is strong.
-				if node.NodeConfig.ShardID == shard.BeaconChainShardID {
+				if node.IsRunningBeaconChain() {
 					node.BroadcastNewBlock(newBlock)
 				}
 				node.BroadcastCXReceipts(newBlock)
diff --git a/node/node_syncing.go b/node/node_syncing.go
index 75ace9333..2f7e32cc8 100644
--- a/node/node_syncing.go
+++ b/node/node_syncing.go
@@ -9,17 +9,22 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/rlp"
+	lru "github.com/hashicorp/golang-lru"
+	"github.com/pkg/errors"
+
+	"github.com/harmony-one/harmony/api/service"
 	"github.com/harmony-one/harmony/api/service/legacysync"
-	"github.com/harmony-one/harmony/api/service/legacysync/downloader"
+	legdownloader "github.com/harmony-one/harmony/api/service/legacysync/downloader"
 	downloader_pb "github.com/harmony-one/harmony/api/service/legacysync/downloader/proto"
+	"github.com/harmony-one/harmony/api/service/synchronize"
 	"github.com/harmony-one/harmony/core"
 	"github.com/harmony-one/harmony/core/types"
+	"github.com/harmony-one/harmony/hmy/downloader"
 	nodeconfig "github.com/harmony-one/harmony/internal/configs/node"
 	"github.com/harmony-one/harmony/internal/utils"
 	"github.com/harmony-one/harmony/node/worker"
 	"github.com/harmony-one/harmony/p2p"
-	lru "github.com/hashicorp/golang-lru"
-	"github.com/pkg/errors"
+	"github.com/harmony-one/harmony/shard"
 )
 
 // Constants related to doing syncing.
@@ -33,6 +38,16 @@ func init() {
 	rand.Seed(time.Now().UnixNano())
 }
 
+// BeaconSyncHook is the hook function called after inserted beacon in downloader
+// TODO: This is a small misc piece of consensus logic. Better put it to consensus module.
+func (node *Node) BeaconSyncHook() {
+	if node.Consensus.IsLeader() {
+		// TODO: Instead of leader, it would better be validator do this broadcast since leader do
+		//       not have much idle resources.
+		node.BroadcastCrossLink()
+	}
+}
+
 // GenerateRandomString generates a random string with given length
 func GenerateRandomString(n int) string {
 	b := make([]rune, n)
@@ -176,28 +191,31 @@ func (p *LocalSyncingPeerProvider) SyncingPeers(shardID uint32) (peers []p2p.Pee
 	return peers, nil
 }
 
-// DoBeaconSyncing update received beaconchain blocks and downloads missing beacon chain blocks
-func (node *Node) DoBeaconSyncing() {
+// doBeaconSyncing update received beaconchain blocks and downloads missing beacon chain blocks
+func (node *Node) doBeaconSyncing() {
 	if node.NodeConfig.IsOffline {
 		return
 	}
 
-	go func(node *Node) {
-		// TODO ek – infinite loop; add shutdown/cleanup logic
-		for beaconBlock := range node.BeaconBlockChannel {
-			if node.beaconSync != nil {
-				err := node.beaconSync.UpdateBlockAndStatus(
-					beaconBlock, node.Beaconchain(), node.BeaconWorker, true,
-				)
-				if err != nil {
-					node.beaconSync.AddLastMileBlock(beaconBlock)
-				} else if node.Consensus.IsLeader() {
-					// Only leader broadcast crosslink to avoid spamming p2p
-					node.BroadcastCrossLink()
+	if !node.NodeConfig.Downloader {
+		// If Downloader is not working, we need also deal with blocks from beaconBlockChannel
+		go func(node *Node) {
+			// TODO ek – infinite loop; add shutdown/cleanup logic
+			for beaconBlock := range node.BeaconBlockChannel {
+				if node.beaconSync != nil {
+					err := node.beaconSync.UpdateBlockAndStatus(
+						beaconBlock, node.Beaconchain(), node.BeaconWorker, true,
+					)
+					if err != nil {
+						node.beaconSync.AddLastMileBlock(beaconBlock)
+					} else if node.Consensus.IsLeader() {
+						// Only leader broadcast crosslink to avoid spamming p2p
+						node.BroadcastCrossLink()
+					}
 				}
 			}
-		}
-	}(node)
+		}(node)
+	}
 
 	// TODO ek – infinite loop; add shutdown/cleanup logic
 	for {
@@ -279,16 +297,25 @@ func (node *Node) doSync(bc *core.BlockChain, worker *worker.Worker, willJoinCon
 	node.IsInSync.Set()
 }
 
-// SupportBeaconSyncing sync with beacon chain for archival node in beacon chan or non-beacon node
-func (node *Node) SupportBeaconSyncing() {
-	go node.DoBeaconSyncing()
-}
-
-// SupportSyncing keeps sleeping until it's doing consensus or it's a leader.
-func (node *Node) SupportSyncing() {
+// SupportGRPCSyncServer do gRPC sync server
+func (node *Node) SupportGRPCSyncServer() {
 	node.InitSyncingServer()
 	node.StartSyncingServer()
+}
 
+// StartGRPCSyncClient start the legacy gRPC sync process
+func (node *Node) StartGRPCSyncClient() {
+	if node.Blockchain().ShardID() != shard.BeaconChainShardID {
+		utils.Logger().Info().
+			Uint32("shardID", node.Blockchain().ShardID()).
+			Msg("SupportBeaconSyncing")
+		go node.doBeaconSyncing()
+	}
+	node.supportSyncing()
+}
+
+// supportSyncing keeps sleeping until it's doing consensus or it's a leader.
+func (node *Node) supportSyncing() {
 	joinConsensus := false
 	// Check if the current node is explorer node.
 	switch node.NodeConfig.Role() {
@@ -313,7 +340,7 @@ func (node *Node) SupportSyncing() {
 // InitSyncingServer starts downloader server.
 func (node *Node) InitSyncingServer() {
 	if node.downloaderServer == nil {
-		node.downloaderServer = downloader.NewServer(node)
+		node.downloaderServer = legdownloader.NewServer(node)
 	}
 }
 
@@ -466,7 +493,7 @@ func (node *Node) CalculateResponse(request *downloader_pb.DownloaderRequest, in
 		} else {
 			response.Type = downloader_pb.DownloaderResponse_FAIL
 			syncPort := legacysync.GetSyncingPort(port)
-			client := downloader.ClientSetup(ip, syncPort)
+			client := legdownloader.ClientSetup(ip, syncPort)
 			if client == nil {
 				utils.Logger().Warn().
 					Str("ip", ip).
@@ -540,12 +567,49 @@ func (node *Node) getEncodedBlockByHash(hash common.Hash) ([]byte, error) {
 	return b, nil
 }
 
-// GetMaxPeerHeight ...
-func (node *Node) GetMaxPeerHeight() uint64 {
-	return node.stateSync.GetMaxPeerHeight()
+// SyncStatus return the syncing status, including whether node is syncing
+// and the target block number.
+func (node *Node) SyncStatus(shardID uint32) (bool, uint64) {
+	ds := node.getDownloaders()
+	if ds == nil {
+		return false, 0
+	}
+	return ds.SyncStatus(shardID)
+}
+
+// IsOutOfSync return whether the node is out of sync of the given hsardID
+func (node *Node) IsOutOfSync(shardID uint32) bool {
+	ds := node.getDownloaders()
+	if ds == nil {
+		return false
+	}
+	isSyncing, _ := ds.SyncStatus(shardID)
+	return !isSyncing
 }
 
-// IsOutOfSync ...
-func (node *Node) IsOutOfSync(bc *core.BlockChain) bool {
-	return node.stateSync.IsOutOfSync(bc, false)
+// SyncPeers return connected sync peers for each shard
+func (node *Node) SyncPeers() map[string]int {
+	ds := node.getDownloaders()
+	if ds == nil {
+		return nil
+	}
+	nums := ds.NumPeers()
+	res := make(map[string]int)
+	for sid, num := range nums {
+		s := fmt.Sprintf("shard-%v", sid)
+		res[s] = num
+	}
+	return res
+}
+
+func (node *Node) getDownloaders() *downloader.Downloaders {
+	syncService := node.serviceManager.GetService(service.Synchronize)
+	if syncService == nil {
+		return nil
+	}
+	dsService, ok := syncService.(*synchronize.Service)
+	if !ok {
+		return nil
+	}
+	return dsService.Downloaders
 }
diff --git a/p2p/host.go b/p2p/host.go
index ba8b1ad77..020f45969 100644
--- a/p2p/host.go
+++ b/p2p/host.go
@@ -10,6 +10,8 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/libp2p/go-libp2p-core/protocol"
+
 	"github.com/harmony-one/bls/ffi/go/bls"
 	nodeconfig "github.com/harmony-one/harmony/internal/configs/node"
 	"github.com/harmony-one/harmony/internal/utils"
@@ -230,8 +232,9 @@ func (host *HostV2) C() (int, int, int) {
 // AddStreamProtocol adds the stream protocols to the host to be started and closed
 // when the host starts or close
 func (host *HostV2) AddStreamProtocol(protocols ...sttypes.Protocol) {
-	for _, protocol := range protocols {
-		host.streamProtos = append(host.streamProtos, protocol)
+	for _, proto := range protocols {
+		host.streamProtos = append(host.streamProtos, proto)
+		host.h.SetStreamHandlerMatch(protocol.ID(proto.ProtoID()), proto.Match, proto.HandleStream)
 	}
 }
 
diff --git a/rosetta/services/network.go b/rosetta/services/network.go
index 707feb24a..2b4d5709a 100644
--- a/rosetta/services/network.go
+++ b/rosetta/services/network.go
@@ -82,12 +82,12 @@ func (s *NetworkAPI) NetworkStatus(
 	if rosettaError != nil {
 		return nil, rosettaError
 	}
-	targetHeight := int64(s.hmy.NodeAPI.GetMaxPeerHeight())
+	isSyncing, targetHeight := s.hmy.NodeAPI.SyncStatus(s.hmy.BlockChain.ShardID())
 	syncStatus := common.SyncingFinish
-	if s.hmy.NodeAPI.IsOutOfSync(s.hmy.BlockChain) {
-		syncStatus = common.SyncingNewBlock
-	} else if targetHeight == 0 {
+	if targetHeight == 0 {
 		syncStatus = common.SyncingUnknown
+	} else if isSyncing {
+		syncStatus = common.SyncingNewBlock
 	}
 	stage := syncStatus.String()
 
@@ -116,6 +116,13 @@ func (s *NetworkAPI) NetworkStatus(
 		}
 	}
 
+	targetInt := int64(targetHeight)
+	ss := &types.SyncStatus{
+		CurrentIndex: currentHeader.Number().Int64(),
+		TargetIndex:  &targetInt,
+		Stage:        &stage,
+	}
+
 	return &types.NetworkStatusResponse{
 		CurrentBlockIdentifier: currentBlockIdentifier,
 		OldestBlockIdentifier:  oldestBlockIdentifier,
@@ -124,12 +131,8 @@ func (s *NetworkAPI) NetworkStatus(
 			Index: genesisHeader.Number().Int64(),
 			Hash:  genesisHeader.Hash().String(),
 		},
-		Peers: peers,
-		SyncStatus: &types.SyncStatus{
-			CurrentIndex: currentHeader.Number().Int64(),
-			TargetIndex:  &targetHeight,
-			Stage:        &stage,
-		},
+		Peers:      peers,
+		SyncStatus: ss,
 	}, nil
 }
 
diff --git a/rpc/blockchain.go b/rpc/blockchain.go
index 88032e41d..b27667165 100644
--- a/rpc/blockchain.go
+++ b/rpc/blockchain.go
@@ -685,12 +685,12 @@ func (s *PublicBlockchainService) GetStakingNetworkInfo(
 
 // InSync returns if shard chain is syncing
 func (s *PublicBlockchainService) InSync(ctx context.Context) (bool, error) {
-	return !s.hmy.NodeAPI.IsOutOfSync(s.hmy.BlockChain), nil
+	return !s.hmy.NodeAPI.IsOutOfSync(s.hmy.BlockChain.ShardID()), nil
 }
 
 // BeaconInSync returns if beacon chain is syncing
 func (s *PublicBlockchainService) BeaconInSync(ctx context.Context) (bool, error) {
-	return !s.hmy.NodeAPI.IsOutOfSync(s.hmy.BeaconChain), nil
+	return !s.hmy.NodeAPI.IsOutOfSync(s.hmy.BeaconChain.ShardID()), nil
 }
 
 func isBlockGreaterThanLatest(hmy *hmy.Harmony, blockNum rpc.BlockNumber) bool {
diff --git a/rpc/common/types.go b/rpc/common/types.go
index 69e418d02..253b6bd14 100644
--- a/rpc/common/types.go
+++ b/rpc/common/types.go
@@ -64,6 +64,7 @@ type NodeMetadata struct {
 	PeerID         peer.ID            `json:"peerid"`
 	Consensus      ConsensusInternal  `json:"consensus"`
 	C              C                  `json:"p2p-connectivity"`
+	SyncPeers      map[string]int     `json:"sync-peers",omitempty`
 }
 
 // P captures the connected peers per topic