Rapid UML

"A schedule or timetable is a basic time management tool consisting of a list of times at which possible tasks, events, or actions are intended to take place, or a sequence of events in the chronological order in which such things are intended to take place. The process of creating a schedule - deciding how to order these tasks and how to commit resources between the variety of possible tasks - is called scheduling, and a person responsible for making a particular schedule may be called a scheduler. Making and following schedules is a fundamental human activity, and learning to do these things effectively is one of the most basic life skills. There are a wide variety of situations in which schedules are necessary, or at least useful.
Schedules are useful for both short periods, such as a daily or weekly schedule, and for long term planning with respect to periods of several months or years. They are often made using a calendar, where the person making the schedule can note the dates and times at which various events are planned to occur. Schedules that do not set forth specific times for events to occur may instead list an expected order in which events either can or must take place." [Schedule. Wikipedia]
The UML sequence diagram example "Checking process" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"Request methods.
An HTTP 1.1 request made using telnet. The request, response headers and response body are highlighted.
HTTP defines methods (sometimes referred to as verbs) to indicate the desired action to be performed on the identified resource. What this resource represents, whether pre-existing data or data that is generated dynamically, depends on the implementation of the server. Often, the resource corresponds to a file or the output of an executable residing on the server. The HTTP/ 1.0 specification:section 8 defined the GET, POST and HEAD methods and the HTTP/ 1.1 specification:section 9 added 5 new methods: OPTIONS, PUT, DELETE, TRACE and CONNECT. By being specified in these documents their semantics are well known and can be depended upon. Any client can use any method and the server can be configured to support any combination of methods. If a method is unknown to an intermediate it will be treated as an unsafe and non-idempotent method. There is no limit to the number of methods that can be defined and this allows for future methods to be specified without breaking existing infrastructure. For example, WebDAV defined 7 new methods and RFC5789 specified the PATCH method.
GET.
Requests a representation of the specified resource. Requests using GET should only retrieve data and should have no other effect. (This is also true of some other HTTP methods.)" [Hypertext Transfer Protocol. Wikipedia]
The UML sequence diagram example "GET request" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

"Sequence diagram is the most common kind of interaction diagram, which focuses on the message interchange between a number of lifelines.
Sequence diagram describes an interaction by focusing on the sequence of messages that are exchanged, along with their corresponding occurrence specifications on the lifelines.
The following nodes and edges are typically drawn in a UML sequence diagram: lifeline, execution specification, message, combined fragment, interaction use, state invariant, continuation, destruction occurrence." [uml-diagrams.org/ sequence-diagrams.html]
The template "UML sequence diagram" for the ConceptDraw PRO diagramming and vector drawing software is included in the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.
www.conceptdraw.com/ solution-park/ software-uml