diff --git a/src/contacts/interfaces/contacts.interfaces.ts b/src/contacts/interfaces/contacts.interfaces.ts
index d36f9a0..6e31cf5 100644
--- a/src/contacts/interfaces/contacts.interfaces.ts
+++ b/src/contacts/interfaces/contacts.interfaces.ts
@@ -14,8 +14,8 @@ export interface Contact {
 export interface ContactDB extends Document, Contact {}
 
 export declare interface ContactsService {
-  add(contact: Contact): void
+  add(contact: Contact): Promise<void>
   list(): Promise<Contact[]>
   findByAddress(address: PublicIdentity['address']): Promise<Optional<Contact>>
-  removeAll(): void
+  removeAll(): Promise<void>
 }
diff --git a/src/ctypes/interfaces/ctype.interfaces.ts b/src/ctypes/interfaces/ctype.interfaces.ts
index d0b24cc..d8622d0 100644
--- a/src/ctypes/interfaces/ctype.interfaces.ts
+++ b/src/ctypes/interfaces/ctype.interfaces.ts
@@ -17,5 +17,5 @@ export declare interface CTypeService {
   register(cType: CType): Promise<boolean>
   findByHash(hash: ICType['hash']): Promise<Optional<CType>>
   findAll(): Promise<CType[]>
-  removeAll(): void
+  removeAll(): Promise<void>
 }
diff --git a/src/messaging/interfaces/messaging.interfaces.ts b/src/messaging/interfaces/messaging.interfaces.ts
index 0033380..7e89063 100644
--- a/src/messaging/interfaces/messaging.interfaces.ts
+++ b/src/messaging/interfaces/messaging.interfaces.ts
@@ -5,7 +5,7 @@ import { IEncryptedMessage } from '@kiltprotocol/sdk-js'
 export interface MessageDB extends Document, IEncryptedMessage {}
 
 export declare interface MessagingService {
-  add(message: IEncryptedMessage): void
+  add(message: IEncryptedMessage): Promise<void>
 
   findBySenderAddress(
     senderAddress: Contact['publicIdentity']['address']
@@ -15,7 +15,7 @@ export declare interface MessagingService {
     receiverAddress: Contact['publicIdentity']['address']
   ): Promise<IEncryptedMessage[]>
 
-  remove(messageId: string): void
+  remove(messageId: string): Promise<void>
 
-  removeAll(): void
+  removeAll(): Promise<void>
 }