Syntax

Each line in a sequence diagram consists of two columns (i.e. entities), an arrow (i.e. direction of flow), and a message. The two columns are separated by the > arrow and the message is prepended with the :.

Here is an example:

Web App > DB: Start transaction

Here are the types of arrows:

Arrow	Syntax	Description
	`>`	Left-to-right arrow
	`<`	Right-to-left arrow
	`<>`	Bi-directional arrow
	`-`	Line
	`--`	Dotted line
	`-->`	Dotted arrow

Each line is parsed in sequential order from top to bottom and rendered in the diagram the same way.

Column names are required to be unique. If a line refers to a column name that hasn't been used in prior lines, a new column will be created.

Properties

Properties are key-value pairs enclosed in [ ] brackets that can be appended to column names. Properties are optional.

It is possible to set multiple properties like shown below:

Web App [icon: monitor, color: blue] > DB [icon: database, color: green]: Start transaction

Here are the properties that are allowed:

Property	Description	Value
`Icon`	Attached icons	Icon names (e.g. `aws-ec2`). See Icons page for full list.
`Color`	Stroke and fill color, when possible	Color name (e.g. `blue`) or hex code (e.g. `#000000`)

Here are the lists of icon names: