@startuml
!includeurl https://raw.githubusercontent.com/RicardoNiepel/C4-PlantUML/master/C4_Container.puml

LAYOUT_WITH_LEGEND

title Container diagram for Internet Banking System

Person(pbc, "Personal Banking Customer", "A customer of the bank, with personal bank accounts.")
System_Ext(es, "E-mail system", "The internal Microsoft Exchange e-mail system.")
System_Ext(mbs, "Mainframe Banking System", "Stores all of the core banking information about customers, accounts, transactions, etc.")
System_Boundary(ibs, "Internet Banking") {
    Container(wa, "Web Application", "java and Spring MVC", "Delivers the static content and the internet banking single page application.")
    Container(spa, "Single Page Application", "javascript and angular", "Provides all the internet banking functionality to customers via their web browser.")
    Container(ma, "Mobile App", "Xamarin", "Provides a limited subset ot the internet banking functionality to customers via their mobile mobile device.")
    Container(db, "Database", "Relational Database Schema", "Stores user registration information, hashed authentication credentials, access logs, etc.")
    Container(api, "API Application", "java and String MVC", "Provides internet banking functionality via a JSON/HTTP API.")

    Rel(api, es, "Sends e-mails", "SMTP")
    Rel(api, mbs, "Uses", "XML/HTTPS")
    Rel(api, db, "Reads & writes to", "JDBC")
    Rel(wa, spa, "Delivers")
    Rel(spa, api, "Uses", "JSON/HTTPS")
    Rel(ma, api, "Uses", "JSON/HTTPS")
}

Rel(pbc, wa, "Uses", "HTTPS")
Rel(pbc, spa, "Uses")
Rel(pbc, ma, "Uses")
Rel(es, pbc, "Sends e-mails to")
@enduml