diff --git a/internal/app/db/db.go b/internal/app/db/db.go
index 98a0440f..92dcb05f 100644
--- a/internal/app/db/db.go
+++ b/internal/app/db/db.go
@@ -92,7 +92,6 @@ func migrate() {
 		&model.GameChallenge{},
 		&model.GameTeam{},
 		&model.Flag{},
-		&model.FlagGen{},
 		&model.Port{},
 		&model.Nat{},
 		&model.Env{},
diff --git a/internal/files/i18n/en.yaml b/internal/files/i18n/en.yaml
index 8c4abca3..1252d413 100644
--- a/internal/files/i18n/en.yaml
+++ b/internal/files/i18n/en.yaml
@@ -3,7 +3,14 @@ welcome: "welcome"
 user:
   not_found: "user not found"
   login:
-    password_incorrect: "password incorrect"
+    invalid_password: "password incorrect"
 
 team:
-  not_found: "team not found"
\ No newline at end of file
+  not_found: "team not found"
+  join:
+    invalid_token: "invalid token"
+
+pod:
+  not_found: "pod not found"
+  create:
+    invalid_image: "invalid image"
\ No newline at end of file
diff --git a/internal/files/i18n/zh-Hans.yaml b/internal/files/i18n/zh-Hans.yaml
index 53d720f9..84dbe47e 100644
--- a/internal/files/i18n/zh-Hans.yaml
+++ b/internal/files/i18n/zh-Hans.yaml
@@ -3,7 +3,14 @@ welcome: "欢迎"
 user:
   not_found: "用户不存在"
   login:
-    password_incorrect: "密码错误"
+    invalid_password: "密码错误"
 
 team:
-  not_found: "团队不存在"
\ No newline at end of file
+  not_found: "团队不存在"
+  join:
+    invalid_token: "邀请码无效"
+
+pod:
+  not_found: "实例不存在"
+  create:
+    invalid_image: "无效镜像"
\ No newline at end of file
diff --git a/internal/model/flag_gen.go b/internal/model/flag_gen.go
deleted file mode 100644
index fca72e4e..00000000
--- a/internal/model/flag_gen.go
+++ /dev/null
@@ -1,10 +0,0 @@
-package model
-
-// FlagGen is the generated flag which is injected into the container.
-// It will be generated when Flag's type is "dynamic".
-type FlagGen struct {
-	ID    uint   `json:"id"`
-	Flag  string `gorm:"type:varchar(128);" json:"flag"`
-	PodID uint   `gorm:"not null;" json:"pod_id"`
-	Pod   *Pod   `json:"pod"`
-}
diff --git a/internal/model/pod.go b/internal/model/pod.go
index b21f617c..2a053f7c 100644
--- a/internal/model/pod.go
+++ b/internal/model/pod.go
@@ -12,11 +12,14 @@ type Pod struct {
 	Team        *Team      `gorm:"foreignkey:TeamID;association_foreignkey:ID" json:"team,omitempty"`
 	ChallengeID *uint      `gorm:"index;null;default:null" json:"challenge_id"`
 	Challenge   *Challenge `gorm:"foreignkey:ChallengeID;association_foreignkey:ID" json:"challenge,omitempty"`
+	Flag        string     `json:"flag,omitempty"` // The generated flag, which will be injected into the container.
 	RemovedAt   int64      `json:"removed_at"`
+	CreatedAt   int64      `gorm:"autoUpdateTime:milli" json:"created_at,omitempty"`
 	Nats        []*Nat     `json:"nats,omitempty"`
 }
 
 func (p *Pod) Simplify() {
+	p.Flag = ""
 	if p.Challenge != nil {
 		p.Challenge.Simplify()
 	}
@@ -24,6 +27,5 @@ func (p *Pod) Simplify() {
 
 func (p *Pod) BeforeDelete(db *gorm.DB) (err error) {
 	db.Table("nats").Where("pod_id = ?", p.ID).Delete(&Nat{})
-	db.Table("flag_gens").Where("pod_id = ?", p.ID).Delete(&FlagGen{})
 	return nil
 }
diff --git a/internal/repository/flag_gen.go b/internal/repository/flag_gen.go
deleted file mode 100644
index 1085ca54..00000000
--- a/internal/repository/flag_gen.go
+++ /dev/null
@@ -1,32 +0,0 @@
-package repository
-
-import (
-	"github.com/elabosak233/cloudsdale/internal/model"
-	"gorm.io/gorm"
-)
-
-type IFlagGenRepository interface {
-	Create(flag model.FlagGen) (model.FlagGen, error)
-	FindByPodID(podIDs []uint) ([]model.FlagGen, error)
-}
-
-type FlagGenRepository struct {
-	db *gorm.DB
-}
-
-func NewFlagGenRepository(db *gorm.DB) IFlagGenRepository {
-	return &FlagGenRepository{db: db}
-}
-
-func (t *FlagGenRepository) Create(flag model.FlagGen) (model.FlagGen, error) {
-	result := t.db.Table("flag_gens").Create(&flag)
-	return flag, result.Error
-}
-
-func (t *FlagGenRepository) FindByPodID(podIDs []uint) ([]model.FlagGen, error) {
-	var flags []model.FlagGen
-	result := t.db.Table("flag_gens").
-		Where("pod_id IN ?", podIDs).
-		Find(&flags)
-	return flags, result.Error
-}
diff --git a/internal/repository/repository.go b/internal/repository/repository.go
index c6e67d91..97d459fd 100644
--- a/internal/repository/repository.go
+++ b/internal/repository/repository.go
@@ -25,7 +25,6 @@ type Repository struct {
 	PortRepository          IPortRepository
 	NatRepository           INatRepository
 	EnvRepository           IEnvRepository
-	FlagGenRepository       IFlagGenRepository
 	GameTeamRepository      IGameTeamRepository
 	NoticeRepository        INoticeRepository
 }
@@ -55,7 +54,6 @@ func InitRepository() {
 			PortRepository:          NewPortRepository(d),
 			NatRepository:           NewNatRepository(d),
 			EnvRepository:           NewEnvRepository(d),
-			FlagGenRepository:       NewFlagGenRepository(d),
 			GameTeamRepository:      NewGameTeamRepository(d),
 			NoticeRepository:        NewNoticeRepository(d),
 		}
diff --git a/internal/repository/team.go b/internal/repository/team.go
index 618ee5f6..1dd484e1 100644
--- a/internal/repository/team.go
+++ b/internal/repository/team.go
@@ -11,7 +11,7 @@ type ITeamRepository interface {
 	Update(team model.Team) error
 	Delete(id uint) error
 	Find(req request.TeamFindRequest) ([]model.Team, int64, error)
-	FindById(id uint) (model.Team, error)
+	FindByID(id uint) (model.Team, error)
 }
 
 type TeamRepository struct {
@@ -85,7 +85,7 @@ func (t *TeamRepository) Find(req request.TeamFindRequest) ([]model.Team, int64,
 	return teams, total, result.Error
 }
 
-func (t *TeamRepository) FindById(id uint) (model.Team, error) {
+func (t *TeamRepository) FindByID(id uint) (model.Team, error) {
 	var team model.Team
 	result := t.db.Table("teams").Where("id = ?", id).First(&team)
 	return team, result.Error
diff --git a/internal/repository/user.go b/internal/repository/user.go
index 480f04fa..ed2c0945 100644
--- a/internal/repository/user.go
+++ b/internal/repository/user.go
@@ -10,7 +10,7 @@ type IUserRepository interface {
 	Create(user model.User) error
 	Update(user model.User) error
 	Delete(id uint) error
-	FindById(id uint) (model.User, error)
+	FindByID(id uint) (model.User, error)
 	FindByUsername(username string) (model.User, error)
 	Find(req request.UserFindRequest) ([]model.User, int64, error)
 }
@@ -78,7 +78,7 @@ func (t *UserRepository) Find(req request.UserFindRequest) ([]model.User, int64,
 	return users, total, result.Error
 }
 
-func (t *UserRepository) FindById(id uint) (model.User, error) {
+func (t *UserRepository) FindByID(id uint) (model.User, error) {
 	var user model.User
 	result := t.db.Table("users").
 		Where("id = ?", id).
diff --git a/internal/service/auth.go b/internal/service/auth.go
index 2d766f49..9de8b40a 100644
--- a/internal/service/auth.go
+++ b/internal/service/auth.go
@@ -6,7 +6,10 @@ import (
 )
 
 type IAuthService interface {
+	// CanModifyUser will check if the user can modify the target user.
 	CanModifyUser(user *model.User, targetUserID uint) bool
+
+	// CanModifyTeam will check if the user can modify the target team.
 	CanModifyTeam(user *model.User, targetTeamID uint) bool
 }
 
diff --git a/internal/service/category.go b/internal/service/category.go
index 7007d927..83737a5d 100644
--- a/internal/service/category.go
+++ b/internal/service/category.go
@@ -7,10 +7,17 @@ import (
 )
 
 type ICategoryService interface {
-	Create(req model.Category) (err error)
-	Update(req model.Category) (err error)
-	Find(req request.CategoryFindRequest) (categories []model.Category, err error)
-	Delete(req request.CategoryDeleteRequest) (err error)
+	// Create will create a new category with the given request.
+	Create(req model.Category) error
+
+	// Update will update the category with the given request.
+	Update(req model.Category) error
+
+	// Find will find the category with the given request, and return the categories.
+	Find(req request.CategoryFindRequest) ([]model.Category, error)
+
+	// Delete will delete the category with the given request.
+	Delete(req request.CategoryDeleteRequest) error
 }
 
 type CategoryService struct {
@@ -23,18 +30,18 @@ func NewCategoryService(r *repository.Repository) ICategoryService {
 	}
 }
 
-func (c *CategoryService) Create(req model.Category) (err error) {
+func (c *CategoryService) Create(req model.Category) error {
 	return c.categoryRepository.Create(req)
 }
 
-func (c *CategoryService) Update(req model.Category) (err error) {
+func (c *CategoryService) Update(req model.Category) error {
 	return c.categoryRepository.Update(req)
 }
 
-func (c *CategoryService) Find(req request.CategoryFindRequest) (categories []model.Category, err error) {
+func (c *CategoryService) Find(req request.CategoryFindRequest) ([]model.Category, error) {
 	return c.categoryRepository.Find(req)
 }
 
-func (c *CategoryService) Delete(req request.CategoryDeleteRequest) (err error) {
+func (c *CategoryService) Delete(req request.CategoryDeleteRequest) error {
 	return c.categoryRepository.Delete(req.ID)
 }
diff --git a/internal/service/challenge.go b/internal/service/challenge.go
index 3ecbe5e3..48bf3484 100644
--- a/internal/service/challenge.go
+++ b/internal/service/challenge.go
@@ -8,9 +8,16 @@ import (
 )
 
 type IChallengeService interface {
+	// Find will find the challenge with the given request, and return the challenges and the total number of challenges.
 	Find(req request.ChallengeFindRequest) ([]model.Challenge, int64, error)
+
+	// Create will create a new challenge with the given request.
 	Create(req request.ChallengeCreateRequest) error
+
+	// Update will update the challenge with the given request.
 	Update(req request.ChallengeUpdateRequest) error
+
+	// Delete will delete the challenge with the given request.
 	Delete(id uint) error
 }
 
diff --git a/internal/service/config.go b/internal/service/config.go
index 28334092..daa7a1c3 100644
--- a/internal/service/config.go
+++ b/internal/service/config.go
@@ -6,6 +6,7 @@ import (
 )
 
 type IConfigService interface {
+	// Update will update the config with the given request.
 	Update(req request.ConfigUpdateRequest) error
 }
 
diff --git a/internal/service/flag.go b/internal/service/flag.go
index 5725c328..5ae0eb97 100644
--- a/internal/service/flag.go
+++ b/internal/service/flag.go
@@ -8,8 +8,13 @@ import (
 )
 
 type IFlagService interface {
+	// Create will create a new flag with the given request.
 	Create(req request.FlagCreateRequest) error
+
+	// Update will update the flag with the given request.
 	Update(req request.FlagUpdateRequest) error
+
+	// Delete will delete the flag with the given request.
 	Delete(req request.FlagDeleteRequest) error
 }
 
diff --git a/internal/service/game.go b/internal/service/game.go
index 090cc3c6..5b22aaf8 100644
--- a/internal/service/game.go
+++ b/internal/service/game.go
@@ -11,10 +11,17 @@ import (
 )
 
 type IGameService interface {
-	Find(req request.GameFindRequest) (games []model.Game, total int64, err error)
-	Create(req request.GameCreateRequest) (err error)
-	Update(req request.GameUpdateRequest) (err error)
-	Delete(req request.GameDeleteRequest) (err error)
+	// Find will find games with the given request, and return the games and total count.
+	Find(req request.GameFindRequest) ([]model.Game, int64, error)
+
+	// Create will create a new game with the given request.
+	Create(req request.GameCreateRequest) error
+
+	// Update will update the game with the given request.
+	Update(req request.GameUpdateRequest) error
+
+	// Delete will delete the game with the given request.
+	Delete(req request.GameDeleteRequest) error
 }
 
 type GameService struct {
@@ -39,7 +46,7 @@ func NewGameService(r *repository.Repository) IGameService {
 	}
 }
 
-func (g *GameService) Create(req request.GameCreateRequest) (err error) {
+func (g *GameService) Create(req request.GameCreateRequest) error {
 	publicKey, privateKey, err := ed25519.GenerateKey(rand.Reader)
 	game := model.Game{
 		PublicKey:  base64.StdEncoding.EncodeToString(publicKey),
@@ -50,20 +57,20 @@ func (g *GameService) Create(req request.GameCreateRequest) (err error) {
 	return err
 }
 
-func (g *GameService) Update(req request.GameUpdateRequest) (err error) {
+func (g *GameService) Update(req request.GameUpdateRequest) error {
 	game := model.Game{}
-	err = mapstructure.Decode(req, &game)
+	err := mapstructure.Decode(req, &game)
 	err = g.gameRepository.Update(game)
 	return err
 }
 
-func (g *GameService) Delete(req request.GameDeleteRequest) (err error) {
+func (g *GameService) Delete(req request.GameDeleteRequest) error {
 	return g.gameRepository.Delete(model.Game{
 		ID: req.ID,
 	})
 }
 
-func (g *GameService) Find(req request.GameFindRequest) (games []model.Game, total int64, err error) {
-	games, total, err = g.gameRepository.Find(req)
+func (g *GameService) Find(req request.GameFindRequest) ([]model.Game, int64, error) {
+	games, total, err := g.gameRepository.Find(req)
 	return games, total, err
 }
diff --git a/internal/service/game_challenge.go b/internal/service/game_challenge.go
index ef545310..d0e5e03e 100644
--- a/internal/service/game_challenge.go
+++ b/internal/service/game_challenge.go
@@ -9,9 +9,16 @@ import (
 )
 
 type IGameChallengeService interface {
+	// Find will find the challenges in game with the given request.
 	Find(req request.GameChallengeFindRequest) ([]model.GameChallenge, error)
+
+	// Create will create a new game challenge with the given request.
 	Create(req request.GameChallengeCreateRequest) error
+
+	// Update will update the game challenge with the given request.
 	Update(req request.GameChallengeUpdateRequest) error
+
+	// Delete will delete the game challenge with the given request.
 	Delete(req request.GameChallengeDeleteRequest) error
 }
 
diff --git a/internal/service/game_team.go b/internal/service/game_team.go
index 1a242d4c..ea200019 100644
--- a/internal/service/game_team.go
+++ b/internal/service/game_team.go
@@ -12,9 +12,16 @@ import (
 )
 
 type IGameTeamService interface {
+	// Find will find the game team with the given request.
 	Find(req request.GameTeamFindRequest) ([]model.GameTeam, int64, error)
+
+	// Create will create a new game team with the given request.
 	Create(req request.GameTeamCreateRequest) error
+
+	// Update will update the game team with the given request.
 	Update(req request.GameTeamUpdateRequest) error
+
+	// Delete will delete the game team with the given request.
 	Delete(req request.GameTeamDeleteRequest) error
 }
 
diff --git a/internal/service/media.go b/internal/service/media.go
index f6368999..18d4b971 100644
--- a/internal/service/media.go
+++ b/internal/service/media.go
@@ -10,13 +10,28 @@ import (
 )
 
 type IMediaService interface {
+	// SaveGamePoster will save the game poster to the media folder with the game id as the folder name.
 	SaveGamePoster(id uint, fileHeader *multipart.FileHeader) error
+
+	// DeleteGamePoster will delete the game poster from the media folder with the game id as the folder name.
 	DeleteGamePoster(id uint) error
+
+	// SaveUserAvatar will save the user avatar to the media folder with the user id as the folder name.
 	SaveUserAvatar(id uint, fileHeader *multipart.FileHeader) error
+
+	// DeleteUserAvatar will delete the user avatar from the media folder with the user id as the folder name.
 	DeleteUserAvatar(id uint) error
+
+	// SaveTeamAvatar will save the team avatar to the media folder with the team id as the folder name.
 	SaveTeamAvatar(id uint, fileHeader *multipart.FileHeader) error
+
+	// DeleteTeamAvatar will delete the team avatar from the media folder with the team id as the folder name.
 	DeleteTeamAvatar(id uint) error
+
+	// SaveChallengeAttachment will save the challenge attachment to the media folder with the challenge id as the folder name.
 	SaveChallengeAttachment(id uint, fileHeader *multipart.FileHeader) error
+
+	// DeleteChallengeAttachment will delete the challenge attachment from the media folder with the challenge id as the folder name.
 	DeleteChallengeAttachment(id uint) error
 }
 
diff --git a/internal/service/notice.go b/internal/service/notice.go
index f8c57a71..6762c25c 100644
--- a/internal/service/notice.go
+++ b/internal/service/notice.go
@@ -8,9 +8,16 @@ import (
 )
 
 type INoticeService interface {
+	// Find will find the notice with the given request.
 	Find(req request.NoticeFindRequest) ([]model.Notice, int64, error)
+
+	// Create will create a new notice with the given request.
 	Create(req request.NoticeCreateRequest) error
+
+	// Update will update the notice with the given request.
 	Update(req request.NoticeUpdateRequest) error
+
+	// Delete will delete the notice with the given request.
 	Delete(req request.NoticeDeleteRequest) error
 }
 
diff --git a/internal/service/pod.go b/internal/service/pod.go
index 58d2f1cf..841056af 100644
--- a/internal/service/pod.go
+++ b/internal/service/pod.go
@@ -50,20 +50,19 @@ type PodService struct {
 	challengeRepository repository.IChallengeRepository
 	podRepository       repository.IPodRepository
 	natRepository       repository.INatRepository
-	flagGenRepository   repository.IFlagGenRepository
 }
 
 func NewPodService(r *repository.Repository) IPodService {
 	return &PodService{
 		challengeRepository: r.ChallengeRepository,
-		flagGenRepository:   r.FlagGenRepository,
 		podRepository:       r.PodRepository,
 		natRepository:       r.NatRepository,
 	}
 }
 
-func GenerateFlag(flagFmt string) (flag string) {
-	flag = strings.Replace(flagFmt, "[UUID]", utils.HyphenlessUUID(), -1)
+func GenerateFlag(flag string) string {
+	flag = strings.Replace(flag, "[UUID]", utils.HyphenlessUUID(), -1)
+	flag = strings.Replace(flag, "[uuid]", utils.HyphenlessUUID(), -1)
 	return flag
 }
 
@@ -130,24 +129,22 @@ func (t *PodService) Create(req request.PodCreateRequest) (model.Pod, error) {
 
 	removedAt := time.Now().Add(time.Duration(challenge.Duration) * time.Second).Unix()
 
-	// Select the first one as the target flag which will be injected
-	var flag model.Flag
-	for _, f := range challenge.Flags {
-		if f.Type == "dynamic" {
-			flag = *f
-			flag.Value = GenerateFlag(flag.Value)
-		} else {
-			if f.Env == "" {
-				f.Env = "FLAG"
-			}
-			flag = *f
+	// Select the first one as the target flag which will be injected into the container.
+	generatedFlag := model.Flag{}
+	for _, flag := range challenge.Flags {
+		generatedFlag = *flag
+		if flag.Type == "dynamic" {
+			generatedFlag.Value = GenerateFlag(flag.Value)
+		}
+		if flag.Env == "" {
+			generatedFlag.Env = "FLAG"
 		}
 		break
 	}
 
 	ctnManager := manager.NewContainerManager(
 		challenge,
-		flag,
+		generatedFlag,
 		time.Duration(challenge.Duration)*time.Second,
 	)
 
@@ -161,15 +158,11 @@ func (t *PodService) Create(req request.PodCreateRequest) (model.Pod, error) {
 		TeamID:      req.TeamID,
 		RemovedAt:   removedAt,
 		Nats:        nats,
+		Flag:        generatedFlag.Value,
 	})
 
 	ctnManager.SetPodID(pod.ID)
 
-	_, _ = t.flagGenRepository.Create(model.FlagGen{
-		Flag:  flag.Value,
-		PodID: pod.ID,
-	})
-
 	go func() {
 		if ctnManager.RemoveAfterDuration() {
 			delete(PodManagers, pod.ID)
@@ -193,12 +186,12 @@ func (t *PodService) Renew(req request.PodRenewRequest) error {
 		ID: req.ID,
 	})
 	if total == 0 {
-		return errors.New("实例不存在")
+		return errors.New("pod.not_found")
 	}
 	pod := pods[0]
 	ctn, ok := PodManagers[req.ID]
 	if !ok {
-		return errors.New("实例不存在")
+		return errors.New("pod.not_found")
 	}
 	ctn.Renew(ctn.Duration())
 	pod.RemovedAt = time.Now().Add(ctn.Duration()).Unix()
diff --git a/internal/service/submission.go b/internal/service/submission.go
index 58ea1a6c..6231a510 100644
--- a/internal/service/submission.go
+++ b/internal/service/submission.go
@@ -11,8 +11,13 @@ import (
 )
 
 type ISubmissionService interface {
+	// Create will create a new submission with the given request, and return the status and rank.
 	Create(req request.SubmissionCreateRequest) (status int, rank int64, err error)
-	Delete(id uint) (err error)
+
+	// Delete will delete the submission with the given id.
+	Delete(id uint) error
+
+	// Find will find the submissions with the given request.
 	Find(req request.SubmissionFindRequest) ([]model.Submission, int64, error)
 }
 
@@ -23,7 +28,6 @@ type SubmissionService struct {
 	teamRepository          repository.ITeamRepository
 	userRepository          repository.IUserRepository
 	gameChallengeRepository repository.IGameChallengeRepository
-	flagGenRepository       repository.IFlagGenRepository
 	gameRepository          repository.IGameRepository
 	noticeRepository        repository.INoticeRepository
 }
@@ -36,7 +40,6 @@ func NewSubmissionService(r *repository.Repository) ISubmissionService {
 		teamRepository:          r.TeamRepository,
 		userRepository:          r.UserRepository,
 		gameChallengeRepository: r.GameChallengeRepository,
-		flagGenRepository:       r.FlagGenRepository,
 		gameRepository:          r.GameRepository,
 		noticeRepository:        r.NoticeRepository,
 	}
@@ -53,13 +56,8 @@ func (t *SubmissionService) JudgeDynamicChallenge(req request.SubmissionCreateRe
 	for _, pod := range perhapsPods {
 		podIDs = append(podIDs, pod.ID)
 	}
-	flags, err := t.flagGenRepository.FindByPodID(podIDs)
-	flagMap := make(map[uint]string)
-	for _, flag := range flags {
-		flagMap[flag.PodID] = flag.Flag
-	}
 	for _, pod := range perhapsPods {
-		if req.Flag == flagMap[pod.ID] {
+		if req.Flag == pod.Flag {
 			if (pod.UserID != nil && req.UserID == *(pod.UserID) && req.UserID != 0) || (pod.TeamID != nil && req.TeamID != nil && *(req.TeamID) == *(pod.TeamID)) {
 				status = 2
 			} else {
diff --git a/internal/service/team.go b/internal/service/team.go
index 93e84f5f..1fd76592 100644
--- a/internal/service/team.go
+++ b/internal/service/team.go
@@ -43,7 +43,7 @@ func NewTeamService(r *repository.Repository) ITeamService {
 }
 
 func (t *TeamService) Create(req request.TeamCreateRequest) error {
-	user, err := t.userRepository.FindById(req.CaptainId)
+	user, err := t.userRepository.FindByID(req.CaptainId)
 	if err != nil || user.ID == 0 {
 		return errors.New("user.not_found")
 	}
@@ -61,7 +61,7 @@ func (t *TeamService) Create(req request.TeamCreateRequest) error {
 }
 
 func (t *TeamService) Update(req request.TeamUpdateRequest) error {
-	team, err := t.teamRepository.FindById(req.ID)
+	team, err := t.teamRepository.FindByID(req.ID)
 	if err != nil || team.ID == 0 {
 		return errors.New("team.not_found")
 	}
@@ -77,7 +77,7 @@ func (t *TeamService) Update(req request.TeamUpdateRequest) error {
 }
 
 func (t *TeamService) Delete(id uint) error {
-	team, err := t.teamRepository.FindById(id)
+	team, err := t.teamRepository.FindByID(id)
 	if err != nil || team.ID == 0 {
 		return errors.New("team.not_found")
 	}
@@ -95,7 +95,7 @@ func (t *TeamService) Find(req request.TeamFindRequest) ([]model.Team, int64, er
 }
 
 func (t *TeamService) GetInviteToken(req request.TeamGetInviteTokenRequest) (token string, err error) {
-	team, err := t.teamRepository.FindById(req.ID)
+	team, err := t.teamRepository.FindByID(req.ID)
 	if err != nil || team.ID == 0 {
 		return "", errors.New("team.not_found")
 	}
@@ -103,7 +103,7 @@ func (t *TeamService) GetInviteToken(req request.TeamGetInviteTokenRequest) (tok
 }
 
 func (t *TeamService) UpdateInviteToken(req request.TeamUpdateInviteTokenRequest) (token string, err error) {
-	team, err := t.teamRepository.FindById(req.ID)
+	team, err := t.teamRepository.FindByID(req.ID)
 	if err != nil || team.ID == 0 {
 		return "", errors.New("team.not_found")
 	}
diff --git a/internal/service/user.go b/internal/service/user.go
index 95562173..787ec044 100644
--- a/internal/service/user.go
+++ b/internal/service/user.go
@@ -145,7 +145,7 @@ func (t *UserService) Login(req request.UserLoginRequest) (model.User, string, e
 	}
 	err = bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(req.Password))
 	if err != nil {
-		return user, "", errors.New("user.login.password_incorrect")
+		return user, "", errors.New("user.login.invalid_password")
 	}
 	token, err := t.GetJwtTokenByID(user)
 	return user, token, err
diff --git a/internal/service/user_team.go b/internal/service/user_team.go
index 040f3505..4b957479 100644
--- a/internal/service/user_team.go
+++ b/internal/service/user_team.go
@@ -28,13 +28,16 @@ func NewUserTeamService(r *repository.Repository) IUserTeamService {
 }
 
 func (t *UserTeamService) Join(req request.TeamUserJoinRequest) error {
-	user, err := t.userRepository.FindById(req.UserID)
-	team, err := t.teamRepository.FindById(req.TeamID)
-	if err != nil || user.ID == 0 || team.ID == 0 {
-		return errors.New("user_or_team_not_found")
+	user, err := t.userRepository.FindByID(req.UserID)
+	if err != nil || user.ID == 0 {
+		return errors.New("user.not_found")
+	}
+	team, err := t.teamRepository.FindByID(req.TeamID)
+	if err != nil || team.ID == 0 {
+		return errors.New("team.not_found")
 	}
 	if team.InviteToken != req.InviteToken {
-		return errors.New("invalid_invite_token")
+		return errors.New("team.join.invalid_token")
 	}
 	err = t.userTeamRepository.Create(model.UserTeam{
 		TeamID: team.ID,
@@ -44,10 +47,13 @@ func (t *UserTeamService) Join(req request.TeamUserJoinRequest) error {
 }
 
 func (t *UserTeamService) Create(req request.TeamUserCreateRequest) error {
-	user, err := t.userRepository.FindById(req.UserID)
-	team, err := t.teamRepository.FindById(req.TeamID)
-	if err != nil || user.ID == 0 || team.ID == 0 {
-		return errors.New("user_or_team_not_found")
+	user, err := t.userRepository.FindByID(req.UserID)
+	if err != nil || user.ID == 0 {
+		return errors.New("user.not_found")
+	}
+	team, err := t.teamRepository.FindByID(req.TeamID)
+	if err != nil || team.ID == 0 {
+		return errors.New("team.not_found")
 	}
 	err = t.userTeamRepository.Create(model.UserTeam{
 		TeamID: team.ID,
@@ -57,10 +63,13 @@ func (t *UserTeamService) Create(req request.TeamUserCreateRequest) error {
 }
 
 func (t *UserTeamService) Delete(req request.TeamUserDeleteRequest) error {
-	user, err := t.userRepository.FindById(req.UserID)
-	team, err := t.teamRepository.FindById(req.TeamID)
-	if err != nil || user.ID == 0 || team.ID == 0 {
-		return errors.New("user_or_team_not_found")
+	user, err := t.userRepository.FindByID(req.UserID)
+	if err != nil || user.ID == 0 {
+		return errors.New("user.not_found")
+	}
+	team, err := t.teamRepository.FindByID(req.TeamID)
+	if err != nil || team.ID == 0 {
+		return errors.New("team.not_found")
 	}
 	err = t.userTeamRepository.Delete(model.UserTeam{
 		TeamID: team.ID,