The tools started as a simple command line tools using plantuml's java library to generate diagrams for Event Storming.
To make it easier to share with the team, a web UI is developed.
It works exactly the same way as plantuml.com and it supports not only EML from webeventstorming.com (with addition to support note/comment) but also plantuml code too.

Here's an example of a simple series of commands and events,

(UUU) ABC ->
abc

DEF (UUU) ->
def

(UUU) XXX [1234] ->
xxx

[1234] YYY (UUU) ->
yyy

ZZZ (UUU) [1234] ->
zzz

A Command are suffixed with -> followed by an Event in the next line. Command can be annotated with Persona in bracket and/or User story number in square bracket. The above DSL generates this diagram.

To add Comment to a Command or Event, prefix it with #

ABC ->
# line 1
# line 2
abc
# line a
# line b

DEF ->
deff

To show a Document, suffix with a * and an Invariant with a prefix !

ABC ->
abc
! invariant

DEF ->
def
document*

For External command, suffixed it with -*, instead of ->

A -* // x,y
a

B ->
b

To split into 2 timelines, probably base on some invariants to an event, enclose the two deviated timelines with [] and separate them with ~. Note that the [] must be preceded with a Command + Event and followed with another Command + Event.

X ->
x

[
A -> // x, y
a

B -> // i, j
b

~

A1 -> // x1, y1
a1
]

Y ->
y

A more complicated example can be found here,

Command ->
# hi there
# what's up?
event
document* //one, two, three

[ branch for if this
ABC ->
abc // apple, orange, banana
! if this
~ branch for if that
FGH ->
fgh // airplane, rocket, ship
! if that
document* //what, is, this
[ nested branch a
Nested ->
nested a
~ nested branch b
Nested ->
nested b
] end nest a or b
XYZ ->
xyz
] end if this or that

Done ->
done

Note that:

1. Command, Event and Document can have fields, it's denoted by appending the comma-separated field names prefixed with // to the Command, Event or Document.
2. The text following [, ~ and ] is shown over the arrow and is optional.