diff --git a/cmd/goyco/commands/parallel_processor.go b/cmd/goyco/commands/parallel_processor.go
index fe4ea47..444e56e 100644
--- a/cmd/goyco/commands/parallel_processor.go
+++ b/cmd/goyco/commands/parallel_processor.go
@@ -280,28 +280,53 @@ type voteResult struct {
 	index int
 }
 
+func generateRandomIdentifier() string {
+	const length = 12
+	const chars = "abcdefghijklmnopqrstuvwxyz0123456789"
+	identifier := make([]byte, length)
+	for i := range identifier {
+		num, _ := rand.Int(rand.Reader, big.NewInt(int64(len(chars))))
+		identifier[i] = chars[num.Int64()]
+	}
+	return string(identifier)
+}
+
 func (p *ParallelProcessor) createSingleUser(userRepo repositories.UserRepository, index int) (database.User, error) {
-	username := fmt.Sprintf("user_%d", index)
-	email := fmt.Sprintf("user_%d@goyco.local", index)
 	password := "password123"
+	randomID := generateRandomIdentifier()
+	username := fmt.Sprintf("user_%s", randomID)
+	email := fmt.Sprintf("user_%s@goyco.local", randomID)
 
 	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
 	if err != nil {
 		return database.User{}, fmt.Errorf("hash password: %w", err)
 	}
 
-	user := &database.User{
-		Username:      username,
-		Email:         email,
-		Password:      string(hashedPassword),
-		EmailVerified: true,
+	const maxRetries = 10
+	for attempt := 0; attempt < maxRetries; attempt++ {
+		user, err := userRepo.GetByEmail(email)
+		if err == nil {
+			return *user, nil
+		}
+
+		user = &database.User{
+			Username:      username,
+			Email:         email,
+			Password:      string(hashedPassword),
+			EmailVerified: true,
+		}
+
+		if err := userRepo.Create(user); err != nil {
+			randomID = generateRandomIdentifier()
+			username = fmt.Sprintf("user_%s", randomID)
+			email = fmt.Sprintf("user_%s@goyco.local", randomID)
+			continue
+		}
+
+		return *user, nil
 	}
 
-	if err := userRepo.Create(user); err != nil {
-		return database.User{}, fmt.Errorf("create user: %w", err)
-	}
-
-	return *user, nil
+	return database.User{}, fmt.Errorf("failed to create user after %d attempts", maxRetries)
 }
 
 func (p *ParallelProcessor) createSinglePost(postRepo repositories.PostRepository, authorID uint, index int) (database.Post, error) {
@@ -347,26 +372,35 @@ func (p *ParallelProcessor) createSinglePost(postRepo repositories.PostRepositor
 	}
 
 	domain := sampleDomains[index%len(sampleDomains)]
-	path := generateRandomPath()
+	randomID := generateRandomIdentifier()
+	path := fmt.Sprintf("/article/%s", randomID)
 	url := fmt.Sprintf("https://%s%s", domain, path)
 
 	content := fmt.Sprintf("Autogenerated seed post #%d\n\nThis is sample content for testing purposes. The post discusses %s and provides valuable insights.", index, title)
 
-	post := &database.Post{
-		Title:     title,
-		URL:       url,
-		Content:   content,
-		AuthorID:  &authorID,
-		UpVotes:   0,
-		DownVotes: 0,
-		Score:     0,
+	const maxRetries = 10
+	for attempt := 0; attempt < maxRetries; attempt++ {
+		post := &database.Post{
+			Title:     title,
+			URL:       url,
+			Content:   content,
+			AuthorID:  &authorID,
+			UpVotes:   0,
+			DownVotes: 0,
+			Score:     0,
+		}
+
+		if err := postRepo.Create(post); err != nil {
+			randomID = generateRandomIdentifier()
+			path = fmt.Sprintf("/article/%s", randomID)
+			url = fmt.Sprintf("https://%s%s", domain, path)
+			continue
+		}
+
+		return *post, nil
 	}
 
-	if err := postRepo.Create(post); err != nil {
-		return database.Post{}, fmt.Errorf("create post: %w", err)
-	}
-
-	return *post, nil
+	return database.Post{}, fmt.Errorf("failed to create post after %d attempts", maxRetries)
 }
 
 func (p *ParallelProcessor) createVotesForPost(voteRepo repositories.VoteRepository, users []database.User, post database.Post, avgVotesPerPost int) (int, error) {
@@ -406,8 +440,8 @@ func (p *ParallelProcessor) createVotesForPost(voteRepo repositories.VoteReposit
 			Type:   voteType,
 		}
 
-		if err := voteRepo.Create(vote); err != nil {
-			return totalVotes, fmt.Errorf("create vote: %w", err)
+		if err := voteRepo.CreateOrUpdate(vote); err != nil {
+			return totalVotes, fmt.Errorf("create or update vote: %w", err)
 		}
 
 		totalVotes++
diff --git a/cmd/goyco/commands/seed.go b/cmd/goyco/commands/seed.go
index 4973312..780fa3c 100644
--- a/cmd/goyco/commands/seed.go
+++ b/cmd/goyco/commands/seed.go
@@ -8,11 +8,12 @@ import (
 	"math/big"
 	"os"
 
-	"golang.org/x/crypto/bcrypt"
-	"gorm.io/gorm"
 	"goyco/internal/config"
 	"goyco/internal/database"
 	"goyco/internal/repositories"
+
+	"golang.org/x/crypto/bcrypt"
+	"gorm.io/gorm"
 )
 
 func HandleSeedCommand(cfg *config.Config, name string, args []string) error {
@@ -169,12 +170,12 @@ func seedDatabase(userRepo repositories.UserRepository, postRepo repositories.Po
 	}
 
 	if IsJSONOutput() {
-		outputJSON(map[string]interface{}{
+		outputJSON(map[string]any{
 			"action": "seed_completed",
 			"users":  len(allUsers),
 			"posts":  len(posts),
 			"votes":  votes,
-			"seed_user": map[string]interface{}{
+			"seed_user": map[string]any{
 				"id":       seedUser.ID,
 				"username": seedUser.Username,
 			},
@@ -188,32 +189,41 @@ func seedDatabase(userRepo repositories.UserRepository, postRepo repositories.Po
 }
 
 func ensureSeedUser(userRepo repositories.UserRepository) (*database.User, error) {
-	seedUsername := "seed_admin"
-	seedEmail := "seed_admin@goyco.local"
 	seedPassword := "seed-password"
-
-	user, err := userRepo.GetByEmail(seedEmail)
-	if err == nil {
-		return user, nil
-	}
+	randomID := generateRandomIdentifier()
+	seedUsername := fmt.Sprintf("seed_admin_%s", randomID)
+	seedEmail := fmt.Sprintf("seed_admin_%s@goyco.local", randomID)
 
 	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(seedPassword), bcrypt.DefaultCost)
 	if err != nil {
 		return nil, fmt.Errorf("hash password: %w", err)
 	}
 
-	user = &database.User{
-		Username:      seedUsername,
-		Email:         seedEmail,
-		Password:      string(hashedPassword),
-		EmailVerified: true,
+	const maxRetries = 10
+	for range maxRetries {
+		user, err := userRepo.GetByEmail(seedEmail)
+		if err == nil {
+			return user, nil
+		}
+
+		user = &database.User{
+			Username:      seedUsername,
+			Email:         seedEmail,
+			Password:      string(hashedPassword),
+			EmailVerified: true,
+		}
+
+		if err := userRepo.Create(user); err != nil {
+			randomID = generateRandomIdentifier()
+			seedUsername = fmt.Sprintf("seed_admin_%s", randomID)
+			seedEmail = fmt.Sprintf("seed_admin_%s@goyco.local", randomID)
+			continue
+		}
+
+		return user, nil
 	}
 
-	if err := userRepo.Create(user); err != nil {
-		return nil, fmt.Errorf("create seed user: %w", err)
-	}
-
-	return user, nil
+	return nil, fmt.Errorf("failed to create seed user after %d attempts", maxRetries)
 }
 
 func createRandomUsers(userRepo repositories.UserRepository, count int) ([]database.User, error) {