diff --git a/context.go b/context.go
index 063c72f0..809902a3 100644
--- a/context.go
+++ b/context.go
@@ -711,6 +711,7 @@ func (c *Context) Cookie(name string) (string, error) {
 	return val, nil
 }
 
+// Render writes the response headers and calls render.Render to render data.
 func (c *Context) Render(code int, r render.Render) {
 	c.Status(code)
 
@@ -833,6 +834,7 @@ func (c *Context) SSEvent(name string, message interface{}) {
 	})
 }
 
+// Stream sends a streaming response.
 func (c *Context) Stream(step func(w io.Writer) bool) {
 	w := c.Writer
 	clientGone := w.CloseNotify()
@@ -854,6 +856,7 @@ func (c *Context) Stream(step func(w io.Writer) bool) {
 /******** CONTENT NEGOTIATION *******/
 /************************************/
 
+// Negotiate contains all negotiations data.
 type Negotiate struct {
 	Offered  []string
 	HTMLName string
@@ -863,6 +866,7 @@ type Negotiate struct {
 	Data     interface{}
 }
 
+// Negotiate calls different Render according acceptable Accept format.
 func (c *Context) Negotiate(code int, config Negotiate) {
 	switch c.NegotiateFormat(config.Offered...) {
 	case binding.MIMEJSON:
@@ -882,6 +886,7 @@ func (c *Context) Negotiate(code int, config Negotiate) {
 	}
 }
 
+// NegotiateFormat returns an acceptable Accept format.
 func (c *Context) NegotiateFormat(offered ...string) string {
 	assert1(len(offered) > 0, "you must provide at least one offer")
 
@@ -901,6 +906,7 @@ func (c *Context) NegotiateFormat(offered ...string) string {
 	return ""
 }
 
+// SetAccepted sets Accept header data.
 func (c *Context) SetAccepted(formats ...string) {
 	c.Accepted = formats
 }
diff --git a/errors.go b/errors.go
index 6f90377e..477b9d58 100644
--- a/errors.go
+++ b/errors.go
@@ -12,18 +12,24 @@ import (
 	"github.com/gin-gonic/gin/internal/json"
 )
 
+// ErrorType is an unsigned 64-bit error code as defined in the gin spec.
 type ErrorType uint64
 
 const (
-	ErrorTypeBind    ErrorType = 1 << 63 // used when c.Bind() fails
-	ErrorTypeRender  ErrorType = 1 << 62 // used when c.Render() fails
+	// ErrorTypeBind is used when Context.Bind() fails.
+	ErrorTypeBind ErrorType = 1 << 63
+	// ErrorTypeRender is used when Context.Render() fails.
+	ErrorTypeRender ErrorType = 1 << 62
+	// ErrorTypePrivate indicates a private error.
 	ErrorTypePrivate ErrorType = 1 << 0
-	ErrorTypePublic  ErrorType = 1 << 1
-
+	// ErrorTypePublic indicates a public error.
+	ErrorTypePublic ErrorType = 1 << 1
+	// ErrorTypeAny indicates other any error.
 	ErrorTypeAny ErrorType = 1<<64 - 1
 	ErrorTypeNu            = 2
 )
 
+// Error represents a error's specification.
 type Error struct {
 	Err  error
 	Type ErrorType
@@ -34,11 +40,13 @@ type errorMsgs []*Error
 
 var _ error = &Error{}
 
+// SetType sets the error's type.
 func (msg *Error) SetType(flags ErrorType) *Error {
 	msg.Type = flags
 	return msg
 }
 
+// SetMeta sets the error's meta data.
 func (msg *Error) SetMeta(data interface{}) *Error {
 	msg.Meta = data
 	return msg
@@ -70,11 +78,12 @@ func (msg *Error) MarshalJSON() ([]byte, error) {
 	return json.Marshal(msg.JSON())
 }
 
-// Error implements the error interface
+// Error implements the error interface.
 func (msg Error) Error() string {
 	return msg.Err.Error()
 }
 
+// IsType judges one error.
 func (msg *Error) IsType(flags ErrorType) bool {
 	return (msg.Type & flags) > 0
 }
@@ -138,6 +147,7 @@ func (a errorMsgs) JSON() interface{} {
 	}
 }
 
+// MarshalJSON implements the json.Marshaller interface.
 func (a errorMsgs) MarshalJSON() ([]byte, error) {
 	return json.Marshal(a.JSON())
 }
diff --git a/examples/realtime-advanced/main.go b/examples/realtime-advanced/main.go
index a16c58b0..f3ead476 100644
--- a/examples/realtime-advanced/main.go
+++ b/examples/realtime-advanced/main.go
@@ -20,7 +20,7 @@ func ConfigRuntime() {
 	fmt.Printf("Running with %d CPUs\n", nuCPU)
 }
 
-// StartWrokers start starsWorker by goroutine.
+// StartWorkers start starsWorker by goroutine.
 func StartWorkers() {
 	go statsWorker()
 }
diff --git a/gin.go b/gin.go
index aa62e014..6bff3bd5 100644
--- a/gin.go
+++ b/gin.go
@@ -26,7 +26,10 @@ var (
 	defaultAppEngine bool
 )
 
+// HandlerFunc defines the handler used by gin middleware as return value.
 type HandlerFunc func(*Context)
+
+// HandlersChain defines a HandlerFunc array.
 type HandlersChain []HandlerFunc
 
 // Last returns the last handler in the chain. ie. the last handler is the main own.
@@ -37,12 +40,14 @@ func (c HandlersChain) Last() HandlerFunc {
 	return nil
 }
 
+// RouteInfo represents a request route's specification which contains method and path and its handler.
 type RouteInfo struct {
 	Method  string
 	Path    string
 	Handler string
 }
 
+// RoutesInfo defines a RouteInfo array.
 type RoutesInfo []RouteInfo
 
 // Engine is the framework's instance, it contains the muxer, middleware and configuration settings.
@@ -155,6 +160,7 @@ func (engine *Engine) allocateContext() *Context {
 	return &Context{engine: engine}
 }
 
+// Delims sets template left and right delims and returns a Engine instance.
 func (engine *Engine) Delims(left, right string) *Engine {
 	engine.delims = render.Delims{Left: left, Right: right}
 	return engine
diff --git a/mode.go b/mode.go
index 9df4e45f..7cb0143a 100644
--- a/mode.go
+++ b/mode.go
@@ -11,12 +11,16 @@ import (
 	"github.com/gin-gonic/gin/binding"
 )
 
+// ENV_GIN_MODE indicates environment name for gin mode.
 const ENV_GIN_MODE = "GIN_MODE"
 
 const (
-	DebugMode   = "debug"
+	// DebugMode indicates gin mode is debug.
+	DebugMode = "debug"
+	// ReleaseMode indicates gin mode is relase.
 	ReleaseMode = "release"
-	TestMode    = "test"
+	// TestMode indicates gin mode is test.
+	TestMode = "test"
 )
 const (
 	debugCode = iota
@@ -42,6 +46,7 @@ func init() {
 	SetMode(mode)
 }
 
+// SetMode sets gin mode according to input string.
 func SetMode(value string) {
 	switch value {
 	case DebugMode, "":
@@ -59,14 +64,18 @@ func SetMode(value string) {
 	modeName = value
 }
 
+// DisableBindValidation closes the default validator.
 func DisableBindValidation() {
 	binding.Validator = nil
 }
 
+// EnableJsonDecoderUseNumber sets true for binding.EnableDecoderUseNumberto to
+// call the UseNumber method on the JSON Decoder instance.
 func EnableJsonDecoderUseNumber() {
 	binding.EnableDecoderUseNumber = true
 }
 
+// Mode returns currently gin mode.
 func Mode() string {
 	return modeName
 }
diff --git a/render/html.go b/render/html.go
index 4d3d5812..6696ece9 100644
--- a/render/html.go
+++ b/render/html.go
@@ -46,7 +46,7 @@ type HTML struct {
 
 var htmlContentType = []string{"text/html; charset=utf-8"}
 
-// Instance (HTMLProduction) returns an HTML instance which it realizes Render interface..
+// Instance (HTMLProduction) returns an HTML instance which it realizes Render interface.
 func (r HTMLProduction) Instance(name string, data interface{}) Render {
 	return HTML{
 		Template: r.Template,
@@ -55,7 +55,7 @@ func (r HTMLProduction) Instance(name string, data interface{}) Render {
 	}
 }
 
-// Instance (HTMLDebug) returns an HTML instance which it realizes Render interface..
+// Instance (HTMLDebug) returns an HTML instance which it realizes Render interface.
 func (r HTMLDebug) Instance(name string, data interface{}) Render {
 	return HTML{
 		Template: r.loadTemplate(),
diff --git a/routergroup.go b/routergroup.go
index 876a61b8..be561dee 100644
--- a/routergroup.go
+++ b/routergroup.go
@@ -11,11 +11,13 @@ import (
 	"strings"
 )
 
+// IRouter defines all router handle interface includes single and group router.
 type IRouter interface {
 	IRoutes
 	Group(string, ...HandlerFunc) *RouterGroup
 }
 
+// Iroutes defins all router handle interface.
 type IRoutes interface {
 	Use(...HandlerFunc) IRoutes
 
@@ -34,8 +36,8 @@ type IRoutes interface {
 	StaticFS(string, http.FileSystem) IRoutes
 }
 
-// RouterGroup is used internally to configure router, a RouterGroup is associated with a prefix
-// and an array of handlers (middleware).
+// RouterGroup is used internally to configure router, a RouterGroup is associated with
+// a prefix and an array of handlers (middleware).
 type RouterGroup struct {
 	Handlers HandlersChain
 	basePath string
@@ -61,6 +63,8 @@ func (group *RouterGroup) Group(relativePath string, handlers ...HandlerFunc) *R
 	}
 }
 
+// BasePath returns the base path of router group.
+// For example, if v := router.Group("/rest/n/v1/api"), v.BasePath() is "/rest/n/v1/api".
 func (group *RouterGroup) BasePath() string {
 	return group.basePath
 }