"The C4 model was designed to help describe, document, and diagram custom-built, bespoke software systems. From this perspective, the C4 model can be used to describe a variety of software architectures (monolithic or distributed), built in a variety of programming languages, deployed on a variety of platforms (on-premises or cloud)" - C4Model.com.
sample diagram
@startuml !include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml Person(admin, "Administrator") System_Boundary(c1, "Sample System") { Container(web_app, "Web Application", "C#, ASP.NET Core 2.1 MVC", "Allows users to compare multiple Twitter timelines") } System(twitter, "Twitter") Rel(admin, web_app, "Uses", "HTTPS") Rel(web_app, twitter, "Gets tweets from", "HTTPS") @enduml