diff --git a/LICENSE b/LICENSE
index bfac567..ea1d6f0 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2022 Yusuke Komatsu
+Copyright (c) 2023 Yusuke Komatsu
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index 9a3d675..45d4484 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,11 @@
 # easyindex-cli  <!-- omit in toc -->
 
+`easyindex-cli` makes super easy to use Google Index API and IndexNow API!!
+
+![Demo](demo.gif)
+
+## index  <!-- omit in toc -->
+
 - [preinstall](#preinstall)
 - [required](#required)
 - [install](#install)
@@ -15,6 +21,7 @@
     - [set quota](#set-quota-1)
     - [use csv](#use-csv)
   - [Google \& IndexNow](#google--indexnow)
+  - [Use as Golang package](#use-as-golang-package)
 - [Parameters](#parameters)
   - [common](#common)
   - [Google indexing API](#google-indexing-api)
@@ -196,6 +203,10 @@ easyindex-cli publish --csv index.csv
 easyindex-cli.exe publish --csv index.csv
 ```
 
+### Use as Golang package
+
+ref. [core package](https://github.com/usk81/easyindex)
+
 ## Parameters
 
 ### common
diff --git a/commands/publish.go b/commands/publish.go
index 22dbb5c..e464525 100644
--- a/commands/publish.go
+++ b/commands/publish.go
@@ -65,7 +65,7 @@ Total: {{.Total}}
   [errors]
 {{range $i, $v := .Google.Errors }}  - [{{$v.NotificationType}}] {{$v.URL}} : {{$v.Reason.Error}}
 {{ end -}}
-{{- end -}}
+{{- end }}
 `
 )
 
diff --git a/commands/publish_test.go b/commands/publish_test.go
index 1eb8b3b..27210ea 100644
--- a/commands/publish_test.go
+++ b/commands/publish_test.go
@@ -62,6 +62,7 @@ Total: 2
   [skips]
   - [URL_UPDATED] https://example.com/b70b060b-1997-428d-afa3-35868614500e : Not Found
   - [URL_UPDATED] https://example.com/fabc6b58-827e-4177-827d-a0ee55c8b435 : quota exceeded
+
 `,
 			wantErr: false,
 		},
@@ -106,6 +107,7 @@ Total: 2
   [errors]
   - [URL_UPDATED] https://example.com/b70b060b-1997-428d-afa3-35868614500e : Internal Server Error
   - [URL_UPDATED] https://example.com/fabc6b58-827e-4177-827d-a0ee55c8b435 : Internal Server Error
+
 `,
 			wantErr: false,
 		},
diff --git a/demo.gif b/demo.gif
new file mode 100644
index 0000000..f507215
Binary files /dev/null and b/demo.gif differ
diff --git a/mock/google.go b/mock/google.go
index c054e0f..7430f07 100644
--- a/mock/google.go
+++ b/mock/google.go
@@ -7,21 +7,21 @@ import (
 )
 
 type (
-	PrecheckScenario func(request *google.PublishRequest) (skipReason error)
-	PublishScenario  func(request google.PublishRequest) (skip bool, err error)
+	GooglePrecheckScenario func(request *google.PublishRequest) (skipReason error)
+	GooglePublishScenario  func(request google.PublishRequest) (skip bool, err error)
 
 	mockPublisherImpl struct {
 		config           google.Config
-		precheckScenario PrecheckScenario
-		publishScenario  PublishScenario
+		precheckScenario GooglePrecheckScenario
+		publishScenario  GooglePublishScenario
 		quota            int
 	}
 )
 
 func Publisher(
 	config google.Config,
-	precheck PrecheckScenario,
-	publish PublishScenario,
+	precheck GooglePrecheckScenario,
+	publish GooglePublishScenario,
 ) google.Publisher {
 	quota := 200
 	if config.Quota != nil && *config.Quota > 0 {
diff --git a/mock/indexnow.go b/mock/indexnow.go
new file mode 100644
index 0000000..b4c8078
--- /dev/null
+++ b/mock/indexnow.go
@@ -0,0 +1,55 @@
+package mock
+
+import (
+	"context"
+
+	"github.com/usk81/easyindex/indexnow"
+)
+
+type (
+	IndexNowPrecheckScenario func(request string) (skipReason error)
+	IndexNowSubmitScenario   func(request indexnow.SubmitInput) (err error)
+
+	mockSubmitterrImpl struct {
+		config           indexnow.Config
+		precheckScenario IndexNowPrecheckScenario
+		submitScenario   IndexNowSubmitScenario
+		quota            int
+	}
+)
+
+func Submitter(
+	config indexnow.Config,
+	precheck IndexNowPrecheckScenario,
+	submit IndexNowSubmitScenario,
+) indexnow.Submitter {
+	quota := 10000
+	if config.Quota != nil && *config.Quota > 0 {
+		quota = *config.Quota
+	}
+
+	return &mockSubmitterrImpl{
+		config:           config,
+		precheckScenario: precheck,
+		submitScenario:   submit,
+		quota:            quota,
+	}
+}
+
+func (m *mockSubmitterrImpl) Precheck(ctx context.Context, input []string) (requests []string, skips []indexnow.SkipedPublishRequest) {
+	for _, v := range input {
+		if skip := m.precheckScenario(v); skip != nil {
+			skips = append(skips, indexnow.SkipedPublishRequest{
+				URL:    v,
+				Reason: skip,
+			})
+		} else {
+			requests = append(requests, v)
+		}
+	}
+	return
+}
+
+func (m *mockSubmitterrImpl) Execute(input indexnow.SubmitInput) (err error) {
+	return m.submitScenario(input)
+}