diff --git a/executor.go b/executor.go
index dbe39e7..67cc686 100644
--- a/executor.go
+++ b/executor.go
@@ -6,11 +6,11 @@ import (
 	"reflect"
 	"runtime"
 	"sync"
-	"unsafe"
 
 	"go.uber.org/ratelimit"
 )
 
+// Executor is a simple thread pool base on goroutine.
 type Executor struct {
 	RateLimit  ratelimit.Limiter
 	WaitGroup  *sync.WaitGroup
@@ -18,17 +18,23 @@ type Executor struct {
 	NumWorkers int
 }
 
+// Job is a task will be executor execute.
 type Job struct {
 	Handler interface{}
 	Args    []reflect.Value
 }
 
+// ExecutorConfig is a config of executor.
+// ReqPerSeconds is request per seconds. If it is 0, no limit for requests.
+// QueueSize is size of buffer. Executor use synchronize channel, publisher will waiting if channel is full.
+// NumWorkers is a number of goroutine.
 type ExecutorConfig struct {
 	ReqPerSeconds int
 	QueueSize     int
 	NumWorkers    int
 }
 
+// DefaultExecutorConfig is a default config
 func DefaultExecutorConfig() ExecutorConfig {
 	return ExecutorConfig{
 		ReqPerSeconds: 0,
@@ -37,6 +43,7 @@ func DefaultExecutorConfig() ExecutorConfig {
 	}
 }
 
+// NewExecutor returns a Executors that will manage workers.
 func NewExecutor(config ExecutorConfig) (*Executor, error) {
 	err := config.validate()
 
@@ -60,18 +67,7 @@ func NewExecutor(config ExecutorConfig) (*Executor, error) {
 	return pipeline, nil
 }
 
-type rtype struct {
-}
-type funcType struct {
-	inCount  uint16
-	outCount uint16 // top bit is set if last input parameter is ...
-}
-
-func (t *rtype) NumIn() int {
-	tt := (*funcType)(unsafe.Pointer(t))
-	return int(tt.inCount)
-}
-
+// NewJob returns a Job that will be executed in workers.
 func NewJob(handler interface{}, inputArgs ...interface{}) (*Job, error) {
 	var (
 		err  error
@@ -79,7 +75,7 @@ func NewJob(handler interface{}, inputArgs ...interface{}) (*Job, error) {
 	)
 
 	nArgs := len(inputArgs)
-	parsedHandler, err := getFunc(handler, nArgs)
+	parsedHandler, err := validateFunc(handler, nArgs)
 
 	if err != nil {
 		return nil, err
@@ -95,6 +91,8 @@ func NewJob(handler interface{}, inputArgs ...interface{}) (*Job, error) {
 	}, nil
 }
 
+// Publish to publish a handler and arguments
+// Workers will run handler with provided arguments.
 func (pipeline *Executor) Publish(handler interface{}, inputArgs ...interface{}) error {
 	job, err := NewJob(handler, inputArgs...)
 
@@ -136,16 +134,19 @@ func (pipeline *Executor) runWorker() {
 	}
 }
 
+// Wait for all worker done.
 func (pipeline *Executor) Wait() {
 	pipeline.WaitGroup.Wait()
 }
 
+// Close channel and wait all worker done.
 func (pipeline *Executor) Close() {
 	pipeline.WaitGroup.Wait()
 	close(pipeline.Channel)
 }
 
-func getFunc(handler interface{}, nArgs int) (interface{}, error) {
+// validateFunc validate type of handler and number of arguments.
+func validateFunc(handler interface{}, nArgs int) (interface{}, error) {
 	f := reflect.Indirect(reflect.ValueOf(handler))
 
 	if f.Kind() != reflect.Func {