diff --git a/zrpc/client.go b/zrpc/client.go
index 81d370f3..f3fb199a 100644
--- a/zrpc/client.go
+++ b/zrpc/client.go
@@ -11,23 +11,27 @@ import (
 )
 
 var (
-	WithDialOption             = internal.WithDialOption
-	WithTimeout                = internal.WithTimeout
+	// WithDialOption is an alias of internal.WithDialOption.
+	WithDialOption = internal.WithDialOption
+	// WithTimeout is an alias of internal.WithTimeout.
+	WithTimeout = internal.WithTimeout
+	// WithUnaryClientInterceptor is an alias of internal.WithUnaryClientInterceptor.
 	WithUnaryClientInterceptor = internal.WithUnaryClientInterceptor
 )
 
 type (
+	// Client is an alias of internal.Client.
+	Client = internal.Client
+	// ClientOption is an alias of internal.ClientOption.
 	ClientOption = internal.ClientOption
 
-	Client interface {
-		Conn() *grpc.ClientConn
-	}
-
+	// A RpcClient is a rpc client.
 	RpcClient struct {
 		client Client
 	}
 )
 
+// MustNewClient returns a Client, exits on any error.
 func MustNewClient(c RpcClientConf, options ...ClientOption) Client {
 	cli, err := NewClient(c, options...)
 	if err != nil {
@@ -37,6 +41,7 @@ func MustNewClient(c RpcClientConf, options ...ClientOption) Client {
 	return cli
 }
 
+// NewClient returns a Client.
 func NewClient(c RpcClientConf, options ...ClientOption) (Client, error) {
 	var opts []ClientOption
 	if c.HasCredential() {
@@ -66,6 +71,7 @@ func NewClient(c RpcClientConf, options ...ClientOption) (Client, error) {
 	}, nil
 }
 
+// NewClientNoAuth returns a Client without authentication.
 func NewClientNoAuth(c discov.EtcdConf, opts ...ClientOption) (Client, error) {
 	client, err := internal.NewClient(internal.BuildDiscovTarget(c.Hosts, c.Key), opts...)
 	if err != nil {
@@ -77,10 +83,12 @@ func NewClientNoAuth(c discov.EtcdConf, opts ...ClientOption) (Client, error) {
 	}, nil
 }
 
+// NewClientWithTarget returns a Client with connecting to given target.
 func NewClientWithTarget(target string, opts ...ClientOption) (Client, error) {
 	return internal.NewClient(target, opts...)
 }
 
+// Conn returns the underlying grpc.ClientConn.
 func (rc *RpcClient) Conn() *grpc.ClientConn {
 	return rc.client.Conn()
 }
diff --git a/zrpc/config.go b/zrpc/config.go
index 31c3675c..7188ae98 100644
--- a/zrpc/config.go
+++ b/zrpc/config.go
@@ -7,6 +7,7 @@ import (
 )
 
 type (
+	// A RpcServerConf is a rpc server config.
 	RpcServerConf struct {
 		service.ServiceConf
 		ListenOn      string
@@ -19,6 +20,7 @@ type (
 		CpuThreshold int64 `json:",default=900,range=[0:1000]"`
 	}
 
+	// A RpcClientConf is a rpc client config.
 	RpcClientConf struct {
 		Etcd      discov.EtcdConf `json:",optional"`
 		Endpoints []string        `json:",optional=!Etcd"`
@@ -28,6 +30,7 @@ type (
 	}
 )
 
+// NewDirectClientConf returns a RpcClientConf.
 func NewDirectClientConf(endpoints []string, app, token string) RpcClientConf {
 	return RpcClientConf{
 		Endpoints: endpoints,
@@ -36,6 +39,7 @@ func NewDirectClientConf(endpoints []string, app, token string) RpcClientConf {
 	}
 }
 
+// NewEtcdClientConf returns a RpcClientConf.
 func NewEtcdClientConf(hosts []string, key, app, token string) RpcClientConf {
 	return RpcClientConf{
 		Etcd: discov.EtcdConf{
@@ -47,10 +51,12 @@ func NewEtcdClientConf(hosts []string, key, app, token string) RpcClientConf {
 	}
 }
 
+// HasEtcd checks if there is etcd settings in config.
 func (sc RpcServerConf) HasEtcd() bool {
 	return len(sc.Etcd.Hosts) > 0 && len(sc.Etcd.Key) > 0
 }
 
+// Validate validates the config.
 func (sc RpcServerConf) Validate() error {
 	if sc.Auth {
 		if err := sc.Redis.Validate(); err != nil {
@@ -61,6 +67,7 @@ func (sc RpcServerConf) Validate() error {
 	return nil
 }
 
+// HasCredential checks if there is a credential in config.
 func (cc RpcClientConf) HasCredential() bool {
 	return len(cc.App) > 0 && len(cc.Token) > 0
 }
diff --git a/zrpc/internal/auth/auth.go b/zrpc/internal/auth/auth.go
index 23761409..fe02e6fa 100644
--- a/zrpc/internal/auth/auth.go
+++ b/zrpc/internal/auth/auth.go
@@ -13,6 +13,7 @@ import (
 
 const defaultExpiration = 5 * time.Minute
 
+// An Authenticator is used to authenticate the rpc requests.
 type Authenticator struct {
 	store  *redis.Redis
 	key    string
@@ -20,6 +21,7 @@ type Authenticator struct {
 	strict bool
 }
 
+// NewAuthenticator returns an Authenticator.
 func NewAuthenticator(store *redis.Redis, key string, strict bool) (*Authenticator, error) {
 	cache, err := collection.NewCache(defaultExpiration)
 	if err != nil {
@@ -34,6 +36,7 @@ func NewAuthenticator(store *redis.Redis, key string, strict bool) (*Authenticat
 	}, nil
 }
 
+// Authenticate authenticates the given ctx.
 func (a *Authenticator) Authenticate(ctx context.Context) error {
 	md, ok := metadata.FromIncomingContext(ctx)
 	if !ok {
diff --git a/zrpc/internal/auth/credential.go b/zrpc/internal/auth/credential.go
index 5855113f..72ba57eb 100644
--- a/zrpc/internal/auth/credential.go
+++ b/zrpc/internal/auth/credential.go
@@ -6,11 +6,13 @@ import (
 	"google.golang.org/grpc/metadata"
 )
 
+// A Credential is used to authenticate.
 type Credential struct {
 	App   string
 	Token string
 }
 
+// GetRequestMetadata gets the request metadata.
 func (c *Credential) GetRequestMetadata(context.Context, ...string) (map[string]string, error) {
 	return map[string]string{
 		appKey:   c.App,
@@ -18,10 +20,12 @@ func (c *Credential) GetRequestMetadata(context.Context, ...string) (map[string]
 	}, nil
 }
 
+// RequireTransportSecurity always returns false.
 func (c *Credential) RequireTransportSecurity() bool {
 	return false
 }
 
+// ParseCredential parses credential from given ctx.
 func ParseCredential(ctx context.Context) Credential {
 	var credential Credential
 
diff --git a/zrpc/internal/balancer/p2c/p2c.go b/zrpc/internal/balancer/p2c/p2c.go
index 8125b605..abaee516 100644
--- a/zrpc/internal/balancer/p2c/p2c.go
+++ b/zrpc/internal/balancer/p2c/p2c.go
@@ -20,7 +20,9 @@ import (
 )
 
 const (
-	Name            = "p2c_ewma"
+	// Name is the name of p2c balancer.
+	Name = "p2c_ewma"
+
 	decayTime       = int64(time.Second * 10) // default value from finagle
 	forcePick       = int64(time.Second)
 	initSuccess     = 1000
diff --git a/zrpc/internal/chainclientinterceptors.go b/zrpc/internal/chainclientinterceptors.go
index 3c4fba0c..9465e102 100644
--- a/zrpc/internal/chainclientinterceptors.go
+++ b/zrpc/internal/chainclientinterceptors.go
@@ -2,10 +2,12 @@ package internal
 
 import "google.golang.org/grpc"
 
+// WithStreamClientInterceptors uses given client stream interceptors.
 func WithStreamClientInterceptors(interceptors ...grpc.StreamClientInterceptor) grpc.DialOption {
 	return grpc.WithChainStreamInterceptor(interceptors...)
 }
 
+// WithUnaryClientInterceptors uses given client unary interceptors.
 func WithUnaryClientInterceptors(interceptors ...grpc.UnaryClientInterceptor) grpc.DialOption {
 	return grpc.WithChainUnaryInterceptor(interceptors...)
 }
diff --git a/zrpc/internal/chainserverinterceptors.go b/zrpc/internal/chainserverinterceptors.go
index e6e3b7ae..4d67632e 100644
--- a/zrpc/internal/chainserverinterceptors.go
+++ b/zrpc/internal/chainserverinterceptors.go
@@ -2,10 +2,12 @@ package internal
 
 import "google.golang.org/grpc"
 
+// WithStreamServerInterceptors uses given server stream interceptors.
 func WithStreamServerInterceptors(interceptors ...grpc.StreamServerInterceptor) grpc.ServerOption {
 	return grpc.ChainStreamInterceptor(interceptors...)
 }
 
+// WithUnaryServerInterceptors uses given server unary interceptors.
 func WithUnaryServerInterceptors(interceptors ...grpc.UnaryServerInterceptor) grpc.ServerOption {
 	return grpc.ChainUnaryInterceptor(interceptors...)
 }
diff --git a/zrpc/internal/client.go b/zrpc/internal/client.go
index 08019566..26272fba 100644
--- a/zrpc/internal/client.go
+++ b/zrpc/internal/client.go
@@ -23,11 +23,18 @@ func init() {
 }
 
 type (
+	// Client interface wraps the Conn method.
+	Client interface {
+		Conn() *grpc.ClientConn
+	}
+
+	// A ClientOptions is a client options.
 	ClientOptions struct {
 		Timeout     time.Duration
 		DialOptions []grpc.DialOption
 	}
 
+	// ClientOption defines the method to customize a ClientOptions.
 	ClientOption func(options *ClientOptions)
 
 	client struct {
@@ -35,7 +42,8 @@ type (
 	}
 )
 
-func NewClient(target string, opts ...ClientOption) (*client, error) {
+// NewClient returns a Client.
+func NewClient(target string, opts ...ClientOption) (Client, error) {
 	var cli client
 	opts = append([]ClientOption{WithDialOption(grpc.WithBalancerName(p2c.Name))}, opts...)
 	if err := cli.dial(target, opts...); err != nil {
@@ -92,18 +100,21 @@ func (c *client) dial(server string, opts ...ClientOption) error {
 	return nil
 }
 
+// WithDialOption returns a func to customize a ClientOptions with given dial option.
 func WithDialOption(opt grpc.DialOption) ClientOption {
 	return func(options *ClientOptions) {
 		options.DialOptions = append(options.DialOptions, opt)
 	}
 }
 
+// WithTimeout returns a func to customize a ClientOptions with given timeout.
 func WithTimeout(timeout time.Duration) ClientOption {
 	return func(options *ClientOptions) {
 		options.Timeout = timeout
 	}
 }
 
+// WithUnaryClientInterceptor returns a func to customize a ClientOptions with given interceptor.
 func WithUnaryClientInterceptor(interceptor grpc.UnaryClientInterceptor) ClientOption {
 	return func(options *ClientOptions) {
 		options.DialOptions = append(options.DialOptions, WithUnaryClientInterceptors(interceptor))
diff --git a/zrpc/internal/clientinterceptors/breakerinterceptor.go b/zrpc/internal/clientinterceptors/breakerinterceptor.go
index 2163a497..163aa62b 100644
--- a/zrpc/internal/clientinterceptors/breakerinterceptor.go
+++ b/zrpc/internal/clientinterceptors/breakerinterceptor.go
@@ -9,6 +9,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// BreakerInterceptor is an interceptor that acts as a circuit breaker.
 func BreakerInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	breakerName := path.Join(cc.Target(), method)
diff --git a/zrpc/internal/clientinterceptors/durationinterceptor.go b/zrpc/internal/clientinterceptors/durationinterceptor.go
index b5ace685..5eda2ebf 100644
--- a/zrpc/internal/clientinterceptors/durationinterceptor.go
+++ b/zrpc/internal/clientinterceptors/durationinterceptor.go
@@ -12,6 +12,7 @@ import (
 
 const slowThreshold = time.Millisecond * 500
 
+// DurationInterceptor is an interceptor that logs the processing time.
 func DurationInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	serverName := path.Join(cc.Target(), method)
diff --git a/zrpc/internal/clientinterceptors/prometheusinterceptor.go b/zrpc/internal/clientinterceptors/prometheusinterceptor.go
index a330410c..4efb3385 100644
--- a/zrpc/internal/clientinterceptors/prometheusinterceptor.go
+++ b/zrpc/internal/clientinterceptors/prometheusinterceptor.go
@@ -32,6 +32,7 @@ var (
 	})
 )
 
+// PrometheusInterceptor is an interceptor that reports to prometheus server.
 func PrometheusInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	startTime := timex.Now()
diff --git a/zrpc/internal/clientinterceptors/timeoutinterceptor.go b/zrpc/internal/clientinterceptors/timeoutinterceptor.go
index 86150e02..5d9a380a 100644
--- a/zrpc/internal/clientinterceptors/timeoutinterceptor.go
+++ b/zrpc/internal/clientinterceptors/timeoutinterceptor.go
@@ -8,6 +8,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// TimeoutInterceptor is an interceptor that controls timeout.
 func TimeoutInterceptor(timeout time.Duration) grpc.UnaryClientInterceptor {
 	return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn,
 		invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
diff --git a/zrpc/internal/clientinterceptors/tracinginterceptor.go b/zrpc/internal/clientinterceptors/tracinginterceptor.go
index d05a23a0..afd5312f 100644
--- a/zrpc/internal/clientinterceptors/tracinginterceptor.go
+++ b/zrpc/internal/clientinterceptors/tracinginterceptor.go
@@ -8,6 +8,7 @@ import (
 	"google.golang.org/grpc/metadata"
 )
 
+// TracingInterceptor is an interceptor that handles tracing.
 func TracingInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	ctx, span := trace.StartClientSpan(ctx, cc.Target(), method)
diff --git a/zrpc/internal/codes/accept.go b/zrpc/internal/codes/accept.go
index 91191083..0ecb1275 100644
--- a/zrpc/internal/codes/accept.go
+++ b/zrpc/internal/codes/accept.go
@@ -5,6 +5,7 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+// Acceptable checks if given error is acceptable.
 func Acceptable(err error) bool {
 	switch status.Code(err) {
 	case codes.DeadlineExceeded, codes.Internal, codes.Unavailable, codes.DataLoss:
diff --git a/zrpc/internal/resolver/resolver.go b/zrpc/internal/resolver/resolver.go
index f86009c6..76d56be2 100644
--- a/zrpc/internal/resolver/resolver.go
+++ b/zrpc/internal/resolver/resolver.go
@@ -7,18 +7,25 @@ import (
 )
 
 const (
-	DirectScheme    = "direct"
-	DiscovScheme    = "discov"
+	// DirectScheme stands for direct schema.
+	DirectScheme = "direct"
+	// DiscovSchema stands for discov schema.
+	DiscovScheme = "discov"
+	// EnpointSepChar is the separator cha in endpoints.
 	EndpointSepChar = ','
-	subsetSize      = 32
+
+	subsetSize = 32
 )
 
 var (
+	// EnpointSep is the separator string in endpoints.
 	EndpointSep = fmt.Sprintf("%c", EndpointSepChar)
-	dirBuilder  directBuilder
-	disBuilder  discovBuilder
+
+	dirBuilder directBuilder
+	disBuilder discovBuilder
 )
 
+// RegisterResolver registers the direct and discov schemas to the resolver.
 func RegisterResolver() {
 	resolver.Register(&dirBuilder)
 	resolver.Register(&disBuilder)
diff --git a/zrpc/internal/rpclogger.go b/zrpc/internal/rpclogger.go
index 8761fe98..8cefd149 100644
--- a/zrpc/internal/rpclogger.go
+++ b/zrpc/internal/rpclogger.go
@@ -12,62 +12,77 @@ const errorLevel = 2
 
 var once sync.Once
 
+// A Logger is a rpc logger.
 type Logger struct{}
 
+// InitLogger initializes the rpc logger.
 func InitLogger() {
 	once.Do(func() {
 		grpclog.SetLoggerV2(new(Logger))
 	})
 }
 
+// Error logs the given args into error log.
 func (l *Logger) Error(args ...interface{}) {
 	logx.Error(args...)
 }
 
+// Errorf logs the given args with format into error log.
 func (l *Logger) Errorf(format string, args ...interface{}) {
 	logx.Errorf(format, args...)
 }
 
+// Errorln logs the given args into error log with newline.
 func (l *Logger) Errorln(args ...interface{}) {
 	logx.Error(args...)
 }
 
+// Fatal logs the given args into error log.
 func (l *Logger) Fatal(args ...interface{}) {
 	logx.Error(args...)
 }
 
+// Fatalf logs the given args with format into error log.
 func (l *Logger) Fatalf(format string, args ...interface{}) {
 	logx.Errorf(format, args...)
 }
 
+// Fatalln logs args into error log with newline.
 func (l *Logger) Fatalln(args ...interface{}) {
 	logx.Error(args...)
 }
 
+// Info ignores the grpc info logs.
 func (l *Logger) Info(args ...interface{}) {
 	// ignore builtin grpc info
 }
 
+// Infoln ignores the grpc info logs.
 func (l *Logger) Infoln(args ...interface{}) {
 	// ignore builtin grpc info
 }
 
+// Infof ignores the grpc info logs.
 func (l *Logger) Infof(format string, args ...interface{}) {
 	// ignore builtin grpc info
 }
 
+// V checks if meet required log level.
 func (l *Logger) V(v int) bool {
 	return v >= errorLevel
 }
 
+// Warning ignores the grpc warning logs.
 func (l *Logger) Warning(args ...interface{}) {
 	// ignore builtin grpc warning
 }
 
+// Warningf ignores the grpc warning logs.
 func (l *Logger) Warningf(format string, args ...interface{}) {
 	// ignore builtin grpc warning
 }
 
+// Warningln ignores the grpc warning logs.
 func (l *Logger) Warningln(args ...interface{}) {
 	// ignore builtin grpc warning
 }
diff --git a/zrpc/internal/rpcpubserver.go b/zrpc/internal/rpcpubserver.go
index 334853b5..10ec8014 100644
--- a/zrpc/internal/rpcpubserver.go
+++ b/zrpc/internal/rpcpubserver.go
@@ -13,6 +13,7 @@ const (
 	envPodIp = "POD_IP"
 )
 
+// NewRpcPubServer returns a Server.
 func NewRpcPubServer(etcdEndpoints []string, etcdKey, listenOn string, opts ...ServerOption) (Server, error) {
 	registerEtcd := func() error {
 		pubListenOn := figureOutListenOn(listenOn)
diff --git a/zrpc/internal/rpcserver.go b/zrpc/internal/rpcserver.go
index 2f4a71e9..9d16901d 100644
--- a/zrpc/internal/rpcserver.go
+++ b/zrpc/internal/rpcserver.go
@@ -10,6 +10,7 @@ import (
 )
 
 type (
+	// ServerOption defines the method to customize a rpcServerOptions.
 	ServerOption func(options *rpcServerOptions)
 
 	rpcServerOptions struct {
@@ -26,6 +27,7 @@ func init() {
 	InitLogger()
 }
 
+// NewRpcServer returns a Server.
 func NewRpcServer(address string, opts ...ServerOption) Server {
 	var options rpcServerOptions
 	for _, opt := range opts {
@@ -76,6 +78,7 @@ func (s *rpcServer) Start(register RegisterFn) error {
 	return server.Serve(lis)
 }
 
+// WithMetrics returns a func that sets metrics to a Server.
 func WithMetrics(metrics *stat.Metrics) ServerOption {
 	return func(options *rpcServerOptions) {
 		options.metrics = metrics
diff --git a/zrpc/internal/server.go b/zrpc/internal/server.go
index 98aea89c..10b0c818 100644
--- a/zrpc/internal/server.go
+++ b/zrpc/internal/server.go
@@ -6,8 +6,10 @@ import (
 )
 
 type (
+	// RegisterFn defines the method to register a server.
 	RegisterFn func(*grpc.Server)
 
+	// Server interface represents a rpc server.
 	Server interface {
 		AddOptions(options ...grpc.ServerOption)
 		AddStreamInterceptors(interceptors ...grpc.StreamServerInterceptor)
diff --git a/zrpc/internal/serverinterceptors/authinterceptor.go b/zrpc/internal/serverinterceptors/authinterceptor.go
index 102cac34..06193e99 100644
--- a/zrpc/internal/serverinterceptors/authinterceptor.go
+++ b/zrpc/internal/serverinterceptors/authinterceptor.go
@@ -7,6 +7,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// StreamAuthorizeInterceptor returns a func that uses given authenticator in processing stream requests.
 func StreamAuthorizeInterceptor(authenticator *auth.Authenticator) grpc.StreamServerInterceptor {
 	return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo,
 		handler grpc.StreamHandler) error {
@@ -18,6 +19,7 @@ func StreamAuthorizeInterceptor(authenticator *auth.Authenticator) grpc.StreamSe
 	}
 }
 
+// UnaryAuthorizeInterceptor returns a func that uses given authenticator in processing unary requests.
 func UnaryAuthorizeInterceptor(authenticator *auth.Authenticator) grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo,
 		handler grpc.UnaryHandler) (interface{}, error) {
diff --git a/zrpc/internal/serverinterceptors/crashinterceptor.go b/zrpc/internal/serverinterceptors/crashinterceptor.go
index 8fe32d37..e3126860 100644
--- a/zrpc/internal/serverinterceptors/crashinterceptor.go
+++ b/zrpc/internal/serverinterceptors/crashinterceptor.go
@@ -10,6 +10,7 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+// StreamCrashInterceptor catches panics in processing stream requests and recovers.
 func StreamCrashInterceptor(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo,
 	handler grpc.StreamHandler) (err error) {
 	defer handleCrash(func(r interface{}) {
@@ -19,6 +20,7 @@ func StreamCrashInterceptor(srv interface{}, stream grpc.ServerStream, info *grp
 	return handler(srv, stream)
 }
 
+// UnaryCrashInterceptor catches panics in processing unary requests and recovers.
 func UnaryCrashInterceptor() grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo,
 		handler grpc.UnaryHandler) (resp interface{}, err error) {
diff --git a/zrpc/internal/serverinterceptors/prometheusinterceptor.go b/zrpc/internal/serverinterceptors/prometheusinterceptor.go
index 7925fcba..b0120daf 100644
--- a/zrpc/internal/serverinterceptors/prometheusinterceptor.go
+++ b/zrpc/internal/serverinterceptors/prometheusinterceptor.go
@@ -32,6 +32,7 @@ var (
 	})
 )
 
+// UnaryPrometheusInterceptor returns a func that reports to the prometheus server.
 func UnaryPrometheusInterceptor() grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (
 		interface{}, error) {
diff --git a/zrpc/internal/serverinterceptors/sheddinginterceptor.go b/zrpc/internal/serverinterceptors/sheddinginterceptor.go
index a76f1e73..c1386e6b 100644
--- a/zrpc/internal/serverinterceptors/sheddinginterceptor.go
+++ b/zrpc/internal/serverinterceptors/sheddinginterceptor.go
@@ -16,6 +16,7 @@ var (
 	lock         sync.Mutex
 )
 
+// UnarySheddingInterceptor returns a func that does load shedding on processing unary requests.
 func UnarySheddingInterceptor(shedder load.Shedder, metrics *stat.Metrics) grpc.UnaryServerInterceptor {
 	ensureSheddingStat()
 
diff --git a/zrpc/internal/serverinterceptors/statinterceptor.go b/zrpc/internal/serverinterceptors/statinterceptor.go
index 3c653c62..8eacd4a0 100644
--- a/zrpc/internal/serverinterceptors/statinterceptor.go
+++ b/zrpc/internal/serverinterceptors/statinterceptor.go
@@ -14,6 +14,7 @@ import (
 
 const serverSlowThreshold = time.Millisecond * 500
 
+// UnaryStatInterceptor returns a func that uses given metrics to report stats.
 func UnaryStatInterceptor(metrics *stat.Metrics) grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo,
 		handler grpc.UnaryHandler) (resp interface{}, err error) {
diff --git a/zrpc/internal/serverinterceptors/timeoutinterceptor.go b/zrpc/internal/serverinterceptors/timeoutinterceptor.go
index 26990456..fbd04c53 100644
--- a/zrpc/internal/serverinterceptors/timeoutinterceptor.go
+++ b/zrpc/internal/serverinterceptors/timeoutinterceptor.go
@@ -8,6 +8,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// UnaryTimeoutInterceptor returns a func that sets timeout to incoming unary requests.
 func UnaryTimeoutInterceptor(timeout time.Duration) grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo,
 		handler grpc.UnaryHandler) (resp interface{}, err error) {
diff --git a/zrpc/internal/serverinterceptors/tracinginterceptor.go b/zrpc/internal/serverinterceptors/tracinginterceptor.go
index 50023e5c..3ec81a27 100644
--- a/zrpc/internal/serverinterceptors/tracinginterceptor.go
+++ b/zrpc/internal/serverinterceptors/tracinginterceptor.go
@@ -8,6 +8,7 @@ import (
 	"google.golang.org/grpc/metadata"
 )
 
+// UnaryTracingInterceptor returns a func that handles tracing with given service name.
 func UnaryTracingInterceptor(serviceName string) grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo,
 		handler grpc.UnaryHandler) (resp interface{}, err error) {
diff --git a/zrpc/internal/target.go b/zrpc/internal/target.go
index ff979fa8..25830667 100644
--- a/zrpc/internal/target.go
+++ b/zrpc/internal/target.go
@@ -7,11 +7,13 @@ import (
 	"github.com/tal-tech/go-zero/zrpc/internal/resolver"
 )
 
+// BuildDirectTarget returns a string that represents the given endpoints with direct schema.
 func BuildDirectTarget(endpoints []string) string {
 	return fmt.Sprintf("%s:///%s", resolver.DirectScheme,
 		strings.Join(endpoints, resolver.EndpointSep))
 }
 
+// BuildDiscovTarget returns a string that represents the given endpoints with discov schema.
 func BuildDiscovTarget(endpoints []string, key string) string {
 	return fmt.Sprintf("%s://%s/%s", resolver.DiscovScheme,
 		strings.Join(endpoints, resolver.EndpointSep), key)
diff --git a/zrpc/proxy.go b/zrpc/proxy.go
index f7bc6f79..6bcb7dab 100644
--- a/zrpc/proxy.go
+++ b/zrpc/proxy.go
@@ -10,6 +10,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// A RpcProxy is a rpc proxy.
 type RpcProxy struct {
 	backend     string
 	clients     map[string]Client
@@ -18,6 +19,7 @@ type RpcProxy struct {
 	lock        sync.Mutex
 }
 
+// NewProxy returns a RpcProxy.
 func NewProxy(backend string, opts ...internal.ClientOption) *RpcProxy {
 	return &RpcProxy{
 		backend:     backend,
@@ -27,6 +29,7 @@ func NewProxy(backend string, opts ...internal.ClientOption) *RpcProxy {
 	}
 }
 
+// TakeConn returns a grpc.ClientConn.
 func (p *RpcProxy) TakeConn(ctx context.Context) (*grpc.ClientConn, error) {
 	cred := auth.ParseCredential(ctx)
 	key := cred.App + "/" + cred.Token
diff --git a/zrpc/server.go b/zrpc/server.go
index f1557929..9b367667 100644
--- a/zrpc/server.go
+++ b/zrpc/server.go
@@ -13,11 +13,13 @@ import (
 	"google.golang.org/grpc"
 )
 
+// A RpcServer is a rpc server.
 type RpcServer struct {
 	server   internal.Server
 	register internal.RegisterFn
 }
 
+// MustNewServer returns a RpcSever, exits on any error.
 func MustNewServer(c RpcServerConf, register internal.RegisterFn) *RpcServer {
 	server, err := NewServer(c, register)
 	if err != nil {
@@ -27,6 +29,7 @@ func MustNewServer(c RpcServerConf, register internal.RegisterFn) *RpcServer {
 	return server
 }
 
+// NewServer returns a RpcServer.
 func NewServer(c RpcServerConf, register internal.RegisterFn) (*RpcServer, error) {
 	var err error
 	if err = c.Validate(); err != nil {
@@ -60,18 +63,22 @@ func NewServer(c RpcServerConf, register internal.RegisterFn) (*RpcServer, error
 	return rpcServer, nil
 }
 
+// AddOptions adds given options.
 func (rs *RpcServer) AddOptions(options ...grpc.ServerOption) {
 	rs.server.AddOptions(options...)
 }
 
+// AddStreamInterceptors adds given stream interceptors.
 func (rs *RpcServer) AddStreamInterceptors(interceptors ...grpc.StreamServerInterceptor) {
 	rs.server.AddStreamInterceptors(interceptors...)
 }
 
+// AddUnaryInterceptors adds given unary interceptors.
 func (rs *RpcServer) AddUnaryInterceptors(interceptors ...grpc.UnaryServerInterceptor) {
 	rs.server.AddUnaryInterceptors(interceptors...)
 }
 
+// Start starts the RpcServer.
 func (rs *RpcServer) Start() {
 	if err := rs.server.Start(rs.register); err != nil {
 		logx.Error(err)
@@ -79,6 +86,7 @@ func (rs *RpcServer) Start() {
 	}
 }
 
+// Stop stops the RpcServer.
 func (rs *RpcServer) Stop() {
 	logx.Close()
 }