Diagrams with zoom

sequenceDiagram participant web as Web Browser participant blog as Blog Service participant account as Account Service participant mail as Mail Service participant db as Storage Note over web,db: The user must be logged in to submit blog posts web->>+account: Logs in using credentials account->>db: Query stored accounts db->>account: Respond with query result alt Credentials not found account->>web: Invalid credentials else Credentials found account->>-web: Successfully logged in Note over web,db: When the user is authenticated, they can now submit new posts web->>+blog: Submit new post blog->>db: Store post data par Notifications blog--)mail: Send mail to blog subscribers blog--)db: Store in-site notifications and Response blog-->>-web: Successfully posted end end