diff --git a/services/character/character.go b/services/character/character.go
index 4f64ceb..c946879 100644
--- a/services/character/character.go
+++ b/services/character/character.go
@@ -11,31 +11,31 @@ import (
 // The example methods log the requests and return zero values.
 type charactersrvc struct {
 	logger     *log.Logger
-	characters map[string]*character.Character
+	characters *map[string]*character.Character
 }
 
 // NewCharacter returns the character service implementation.
 func NewCharacter(logger *log.Logger) character.Service {
 	characterMap := make(map[string]*character.Character)
-	return &charactersrvc{logger, characterMap}
+	return &charactersrvc{logger, &characterMap}
 }
 
 // GetCharacter implements getCharacter.
 func (s *charactersrvc) GetCharacter(ctx context.Context, p *character.GetCharacterPayload) (res *character.Character, err error) {
 	s.logger.Print("character.getCharacter")
 
-	itemToGet := s.characters[*p.Name]
+	itemToGet := (*s.characters)[*p.Name]
 	if itemToGet == nil {
 		s.logger.Printf("character with id %d not found", &p.Name)
 		return nil, errors.New("character not found")
 	}
-	res = s.characters[*p.Name]
+	res = (*s.characters)[*p.Name]
 
 	return
 }
 
 func (s *charactersrvc) ListCharacters(ctx context.Context) (res []*character.Character, err error) {
-	for _, value := range s.characters {
+	for _, value := range *s.characters {
 		res = append(res, value)
 	}
 	return
@@ -44,8 +44,15 @@ func (s *charactersrvc) ListCharacters(ctx context.Context) (res []*character.Ch
 // CreateCharacter implements createCharacter.
 func (s *charactersrvc) CreateCharacter(ctx context.Context, p *character.Character) (res *character.Character, err error) {
 	s.logger.Print("character.createCharacter")
-	s.characters[p.Name] = p
-	res = s.characters[p.Name]
+
+	existingCharacter := (*s.characters)[p.Name]
+	if existingCharacter != nil {
+		s.logger.Printf("character with name %d already exists", &p.Name)
+		return nil, errors.New("character already exists")
+	}
+
+	(*s.characters)[p.Name] = p
+	res = (*s.characters)[p.Name]
 	return
 }
 
@@ -53,13 +60,13 @@ func (s *charactersrvc) CreateCharacter(ctx context.Context, p *character.Charac
 func (s *charactersrvc) UpdateCharacter(ctx context.Context, p *character.Character) (res *character.Character, err error) {
 	s.logger.Print("character.updateCharacter")
 
-	itemToUpdate := s.characters[p.Name]
+	itemToUpdate := (*s.characters)[p.Name]
 	if itemToUpdate == nil {
 		s.logger.Printf("characters with id %d not found", &p.Name)
 		return nil, errors.New("characters not found")
 	}
-	s.characters[p.Name] = p
-	res = s.characters[p.Name]
+	(*s.characters)[p.Name] = p
+	res = (*s.characters)[p.Name]
 
 	return
 }
@@ -68,13 +75,13 @@ func (s *charactersrvc) UpdateCharacter(ctx context.Context, p *character.Charac
 func (s *charactersrvc) DeleteCharacter(ctx context.Context, p *character.DeleteCharacterPayload) (err error) {
 	s.logger.Print("character.deleteCharacter")
 
-	itemToDelete := s.characters[*p.Name]
+	itemToDelete := (*s.characters)[*p.Name]
 	if itemToDelete == nil {
 		s.logger.Printf("characters with id %d not found", &p.Name)
 		return errors.New("characters not found")
 	}
 
-	delete(s.characters, *p.Name)
+	delete((*s.characters), *p.Name)
 
 	return
 }
diff --git a/services/inventory/inventory.go b/services/inventory/inventory.go
index bb6d67c..8b59102 100644
--- a/services/inventory/inventory.go
+++ b/services/inventory/inventory.go
@@ -11,25 +11,25 @@ import (
 // The example methods log the requests and return zero values.
 type inventorysrvc struct {
 	logger      *log.Logger
-	inventories map[string]*[]string //key = characterId, value = array of itemIds
+	inventories *map[string]*[]string //key = characterId, value = array of itemIds
 }
 
 // NewInventory returns the inventory service implementation.
 func NewInventory(logger *log.Logger) inventory.Service {
 	inventoryMap := make(map[string]*[]string)
-	return &inventorysrvc{logger, inventoryMap}
+	return &inventorysrvc{logger, &inventoryMap}
 }
 
 // AddItem implements addItem.
 func (s *inventorysrvc) AddItem(ctx context.Context, p *inventory.InventoryRecord) (err error) {
 	s.logger.Print("inventory.addItem")
 
-	itemList := s.inventories[p.CharacterName]
+	itemList := (*s.inventories)[p.CharacterName]
 	if itemList == nil {
 		itemList = s.initCharacterInventory(p.CharacterName)
 	}
 	newItemList := append(*itemList, p.ItemName)
-	s.inventories[p.CharacterName] = &newItemList
+	(*s.inventories)[p.CharacterName] = &newItemList
 
 	return
 }
@@ -38,7 +38,7 @@ func (s *inventorysrvc) AddItem(ctx context.Context, p *inventory.InventoryRecor
 func (s *inventorysrvc) RemoveItem(ctx context.Context, p *inventory.InventoryRecord) (err error) {
 	s.logger.Print("inventory.removeItem")
 
-	itemList := s.inventories[p.CharacterName]
+	itemList := (*s.inventories)[p.CharacterName]
 	if itemList == nil {
 		s.logger.Printf("inventory for character with id %d not found", p.CharacterName)
 		return errors.New("item not found")
@@ -47,7 +47,7 @@ func (s *inventorysrvc) RemoveItem(ctx context.Context, p *inventory.InventoryRe
 	idx := indexOf(p.ItemName, *itemList)
 	if idx != -1 {
 		newItemList := remove(*itemList, idx)
-		s.inventories[p.CharacterName] = &newItemList
+		(*s.inventories)[p.CharacterName] = &newItemList
 	} else {
 		s.logger.Printf("character with id %d does not have item %d in inventory", p.CharacterName, p.ItemName)
 		return errors.New("item not found for character")
@@ -57,10 +57,10 @@ func (s *inventorysrvc) RemoveItem(ctx context.Context, p *inventory.InventoryRe
 }
 
 func (s *inventorysrvc) ListInventory(ctx context.Context, payload *inventory.ListInventoryPayload) (res []string, err error) {
-	if s.inventories[*payload.CharacterName] == nil {
+	if (*s.inventories)[*payload.CharacterName] == nil {
 		return nil, nil
 	}
-	res = *s.inventories[*payload.CharacterName]
+	res = *((*s.inventories)[*payload.CharacterName])
 
 	return
 }
@@ -68,7 +68,7 @@ func (s *inventorysrvc) ListInventory(ctx context.Context, payload *inventory.Li
 func (s *inventorysrvc) initCharacterInventory(characterName string) (itemList *[]string) {
 	list := make([]string, 0)
 	itemList = &list
-	s.inventories[characterName] = itemList
+	(*s.inventories)[characterName] = itemList
 	return
 }
 
diff --git a/services/item/item.go b/services/item/item.go
index bf0d040..e5ad8e7 100644
--- a/services/item/item.go
+++ b/services/item/item.go
@@ -11,25 +11,25 @@ import (
 // The example methods log the requests and return zero values.
 type itemsrvc struct {
 	logger *log.Logger
-	items  map[string]*item.Item
+	items  *map[string]*item.Item
 }
 
 // NewItem returns the item service implementation.
 func NewItem(logger *log.Logger) item.Service {
 	itemsMap := make(map[string]*item.Item)
-	return &itemsrvc{logger, itemsMap}
+	return &itemsrvc{logger, &itemsMap}
 }
 
 // GetItem implements getItem.
 func (s *itemsrvc) GetItem(ctx context.Context, p *item.GetItemPayload) (res *item.Item, err error) {
 	s.logger.Print("itemToGet.getItem")
 
-	itemToGet := s.items[*p.Name]
+	itemToGet := (*s.items)[*p.Name]
 	if itemToGet == nil {
 		s.logger.Printf("item with id %d not found", &p.Name)
 		return nil, errors.New("item not found")
 	}
-	res = s.items[*p.Name]
+	res = (*s.items)[*p.Name]
 
 	return
 }
@@ -37,10 +37,10 @@ func (s *itemsrvc) GetItem(ctx context.Context, p *item.GetItemPayload) (res *it
 func (s *itemsrvc) ListItems(ctx context.Context, payload *item.ListItemsPayload) (res []*item.Item, err error) {
 	if payload.NameFilter != nil {
 		for _, value := range payload.NameFilter {
-			res = append(res, s.items[value])
+			res = append(res, (*s.items)[value])
 		}
 	} else {
-		for _, value := range s.items {
+		for _, value := range *s.items {
 			res = append(res, value)
 		}
 	}
@@ -53,8 +53,14 @@ func (s *itemsrvc) CreateItem(ctx context.Context, p *item.Item) (res *item.Item
 	s.logger.Print("item.createItem")
 	name := p.Name
 
-	s.items[name] = p
-	res = s.items[name]
+	existingItem := (*s.items)[name]
+	if existingItem != nil {
+		s.logger.Printf("item with name %d already exists", &p.Name)
+		return nil, errors.New("item already exists")
+	}
+
+	(*s.items)[name] = p
+	res = (*s.items)[name]
 
 	return
 }
@@ -62,13 +68,13 @@ func (s *itemsrvc) CreateItem(ctx context.Context, p *item.Item) (res *item.Item
 // UpdateItem implements updateItem.
 func (s *itemsrvc) UpdateItem(ctx context.Context, p *item.Item) (res *item.Item, err error) {
 	s.logger.Print("itemToGet.updateItem")
-	itemToUpdate := s.items[p.Name]
+	itemToUpdate := (*s.items)[p.Name]
 	if itemToUpdate == nil {
 		s.logger.Printf("item with id %d not found", &p.Name)
 		return nil, errors.New("item not found")
 	}
-	s.items[p.Name] = p
-	res = s.items[p.Name]
+	(*s.items)[p.Name] = p
+	res = (*s.items)[p.Name]
 
 	return
 }
@@ -76,13 +82,13 @@ func (s *itemsrvc) UpdateItem(ctx context.Context, p *item.Item) (res *item.Item
 // DeleteItem implements deleteItem.
 func (s *itemsrvc) DeleteItem(ctx context.Context, p *item.DeleteItemPayload) (err error) {
 	s.logger.Print("item.deleteItem")
-	itemToDelete := s.items[*p.Name]
+	itemToDelete := (*s.items)[*p.Name]
 	if itemToDelete == nil {
 		s.logger.Printf("item with id %d not found", &p.Name)
 		return errors.New("item not found")
 	}
 
-	delete(s.items, *p.Name)
+	delete((*s.items), *p.Name)
 
 	return
 }