diff --git a/app/internal/domain/permission/codegen/definition/model.go b/app/internal/domain/permission/codegen/definition/model.go
new file mode 100644
index 0000000..fedf7a8
--- /dev/null
+++ b/app/internal/domain/permission/codegen/definition/model.go
@@ -0,0 +1,44 @@
+package definition
+
+type DefaultPermissionValue bool
+
+const (
+	allowedByDefault    DefaultPermissionValue = true
+	restrictedByDefault DefaultPermissionValue = false
+)
+
+func (value DefaultPermissionValue) IsAllowedByDefault() bool {
+	return value == allowedByDefault
+}
+
+type DefinedPermission struct {
+	Name         string
+	DefaultValue DefaultPermissionValue
+}
+
+type DefinedPermissions []DefinedPermission
+
+func permission(name string, value DefaultPermissionValue) DefinedPermission {
+	return DefinedPermission{name, value}
+}
+
+type PermissionDefiner struct {
+	definedPermissions DefinedPermissions
+}
+
+func (def *PermissionDefiner) define(perms ...DefinedPermission) *PermissionDefiner {
+	def.definedPermissions = append(def.definedPermissions, perms...)
+	return def
+}
+
+func (def *PermissionDefiner) GetPermissions() DefinedPermissions {
+	return def.definedPermissions
+}
+
+var definer = &PermissionDefiner{
+	definedPermissions: make(DefinedPermissions, 0, 100),
+}
+
+func GetPermissions() DefinedPermissions {
+	return definer.definedPermissions
+}
diff --git a/app/internal/domain/permission/codegen/definition/permisions_user.go b/app/internal/domain/permission/codegen/definition/permisions_user.go
new file mode 100644
index 0000000..45b0c16
--- /dev/null
+++ b/app/internal/domain/permission/codegen/definition/permisions_user.go
@@ -0,0 +1,15 @@
+package definition
+
+// user permissions
+var _ = definer.define(
+	permission("user.list", restrictedByDefault),
+	permission("user.create", restrictedByDefault),
+	permission("user.edit.nickname", restrictedByDefault),
+	permission("user.delete", restrictedByDefault),
+)
+
+// mypage permissions
+var _ = definer.define(
+	permission("mypage.view", allowedByDefault),
+	permission("mypage.edit.nickname", allowedByDefault),
+)
diff --git a/app/internal/domain/permission/codegen/identifier/identifier.go b/app/internal/domain/permission/codegen/identifier/identifier.go
new file mode 100644
index 0000000..9ab88cd
--- /dev/null
+++ b/app/internal/domain/permission/codegen/identifier/identifier.go
@@ -0,0 +1,50 @@
+package identifier
+
+import (
+	"encoding/json"
+	"github.com/Siroshun09/serrors"
+)
+
+type PermissionIdentifier interface {
+	GetOrCreateID(name string) int16
+	EncodeToJson() ([]byte, error)
+}
+
+type jsonFile struct {
+	PermissionToIdMap map[string]int16 `json:"permissions"`
+	LastUsedID        int16            `json:"last_used_id"`
+}
+
+func DecodeFromJson(data []byte) (PermissionIdentifier, error) {
+	file := &jsonFile{
+		PermissionToIdMap: make(map[string]int16),
+		LastUsedID:        0,
+	}
+
+	if len(data) == 0 {
+		return file, nil
+	}
+
+	if err := json.Unmarshal(data, file); err != nil {
+		return nil, serrors.WithStackTrace(err)
+	}
+	return file, nil
+}
+
+func (i *jsonFile) EncodeToJson() ([]byte, error) {
+	data, err := json.MarshalIndent(*i, "", "  ")
+	if err != nil {
+		return nil, serrors.WithStackTrace(err)
+	}
+	return data, nil
+}
+
+func (i *jsonFile) GetOrCreateID(name string) int16 {
+	if id, ok := i.PermissionToIdMap[name]; ok {
+		return id
+	}
+	i.LastUsedID++
+	id := i.LastUsedID
+	i.PermissionToIdMap[name] = id
+	return id
+}
diff --git a/app/internal/domain/permission/codegen/main.go b/app/internal/domain/permission/codegen/main.go
new file mode 100644
index 0000000..7370aa4
--- /dev/null
+++ b/app/internal/domain/permission/codegen/main.go
@@ -0,0 +1,80 @@
+package main
+
+import (
+	"fmt"
+	"github.com/okocraft/monitor/internal/domain/permission/codegen/definition"
+	"github.com/okocraft/monitor/internal/domain/permission/codegen/identifier"
+	"go/format"
+	"os"
+	"strings"
+	"unicode"
+)
+
+func main() {
+	idFile, err := os.ReadFile("permission_ids.json")
+	if err != nil && !os.IsNotExist(err) {
+		panic(err)
+	}
+
+	idProvider, err := identifier.DecodeFromJson(idFile)
+	if err != nil {
+		panic(err)
+	}
+
+	w := strings.Builder{}
+
+	_, err = w.WriteString("// Code generated by permission/codegen; DO NOT EDIT\n\n")
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = w.WriteString("package permission\n")
+	if err != nil {
+		panic(err)
+	}
+
+	for _, perm := range definition.GetPermissions() {
+		id := idProvider.GetOrCreateID(perm.Name)
+		w.WriteString(fmt.Sprintf(
+			"var %s = Permission{\n"+
+				"ID: %d,\n"+
+				"Name: \"%s\",\n"+
+				"DefaultValue: %v,\n"+
+				"}\n\n",
+			toVarName(perm), id, perm.Name, perm.DefaultValue,
+		))
+	}
+
+	formatted, err := format.Source([]byte(w.String()))
+	err = os.WriteFile("permissions.gen.go", formatted, os.ModePerm)
+	if err != nil {
+		panic(err)
+	}
+
+	data, err := idProvider.EncodeToJson()
+	if err != nil {
+		panic(err)
+	}
+
+	err = os.WriteFile("permission_ids.json", data, os.ModePerm)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func toVarName(perm definition.DefinedPermission) string {
+	upperCase := true
+	varName := strings.Builder{}
+	for _, c := range perm.Name {
+		switch {
+		case c == '.':
+			upperCase = true
+		case upperCase:
+			varName.WriteRune(unicode.ToUpper(c))
+			upperCase = false
+		default:
+			varName.WriteRune(c)
+		}
+	}
+	return varName.String()
+}
diff --git a/app/internal/domain/permission/gen.go b/app/internal/domain/permission/gen.go
new file mode 100644
index 0000000..ff71241
--- /dev/null
+++ b/app/internal/domain/permission/gen.go
@@ -0,0 +1,5 @@
+//go:build tools
+
+package permission
+
+//go:generate go run ./codegen/main.go
diff --git a/app/internal/domain/permission/model.go b/app/internal/domain/permission/model.go
new file mode 100644
index 0000000..6975ea6
--- /dev/null
+++ b/app/internal/domain/permission/model.go
@@ -0,0 +1,9 @@
+package permission
+
+type PermissionID = int16
+
+type Permission struct {
+	ID           PermissionID
+	Name         string
+	DefaultValue bool
+}
diff --git a/app/internal/domain/permission/permission_ids.json b/app/internal/domain/permission/permission_ids.json
new file mode 100644
index 0000000..c342e05
--- /dev/null
+++ b/app/internal/domain/permission/permission_ids.json
@@ -0,0 +1,11 @@
+{
+  "permissions": {
+    "mypage.edit.nickname": 6,
+    "mypage.view": 5,
+    "user.create": 2,
+    "user.delete": 4,
+    "user.edit.nickname": 3,
+    "user.list": 1
+  },
+  "last_used_id": 6
+}
\ No newline at end of file
diff --git a/app/internal/domain/permission/permissions.gen.go b/app/internal/domain/permission/permissions.gen.go
new file mode 100644
index 0000000..49a45ed
--- /dev/null
+++ b/app/internal/domain/permission/permissions.gen.go
@@ -0,0 +1,39 @@
+// Code generated by permission/codegen; DO NOT EDIT
+
+package permission
+
+var UserList = Permission{
+	ID:           1,
+	Name:         "user.list",
+	DefaultValue: false,
+}
+
+var UserCreate = Permission{
+	ID:           2,
+	Name:         "user.create",
+	DefaultValue: false,
+}
+
+var UserEditNickname = Permission{
+	ID:           3,
+	Name:         "user.edit.nickname",
+	DefaultValue: false,
+}
+
+var UserDelete = Permission{
+	ID:           4,
+	Name:         "user.delete",
+	DefaultValue: false,
+}
+
+var MypageView = Permission{
+	ID:           5,
+	Name:         "mypage.view",
+	DefaultValue: true,
+}
+
+var MypageEditNickname = Permission{
+	ID:           6,
+	Name:         "mypage.edit.nickname",
+	DefaultValue: true,
+}