# Sequence diagram ```mermaid sequenceDiagram autonumber actor User participant Web Service participant Backend API participant Database User ->> Web Service: navigate to the landing page Web Service ->>+ Backend API: [GET /profile] request profile for the user Backend API ->>+ Database: query profile Database ->>- Backend API: return profile Backend API ->>- Web Service: return profile Web Service ->> User: see the landing page User ->> Web Service: Update profile Web Service ->>+ Backend API: [POST /profile] Update user profile Backend API ->>+ Database: Save profile to db Database ->>- Backend API: return result Backend API ->>- Web Service: return result Web Service ->> User: see result ``` ```plantuml actor User participant "Web Service" as web_service box "Backend Service" participant "Backend API" as api database "Database" as db end box autonumber autoactivate on User -> web_service: navigate to the landing page web_service -> api: [GET /profile] request profile for the user api -> db: query profile return return profile return return profile return see the landing page User -> web_service: Update profile web_service -> api: [POST /profile] Update user profile api -> db: Save profile to db return return result return return result return see result ```