UML Sequence Markup

With our sequence markup tool, you can create and edit sequence diagrams with ease. Since Lucidchart auto-generates a sequence diagram from the text you enter, you can use the time you save to return to your code… or watch Star Wars.


Follow these steps, and Lucidchart will auto-generate a sequence diagram for you:

  1. Activate the UML shape library. Click “Shapes” at the top of the Toolbar or use the hotkey “M.” Under the Software section, check “UML” or “UML Sequence.” Hit “Save.”
  2. Under the “UML Sequence” category in the Toolbar, click “Use Markup.”

    UML Toolbar
  3. In the pop-over, type your markup.
  4. Click “Build” when you are ready to generate the diagram.

    Build button

To create a new diagram, click “Use Markup” in the UML Sequence shape library again.

Category Syntax Description Example
Lines Alice -> Bob

Alice <- Bob

Draw a solid line (you can draw lines in both directions). SupportedMarkup1.png
Alice --> Draw a dotted line.
Alice -> Alice Draw a solid arrow to and from a participant.
Lifelines activate Alice Start participant activation with lifeline.
deactivate Alice End participant activation ending the lifeline.
Arrows -> Close arrow
-> > Open arrow
- No arrow
Text Alice->Bob: text Add a label to messages between participants. SupportedMarkup2.png
Alice->Bob: Alice->Bob: text\nmore
Notes note left of Alice: text1 Add a note shape on the left of Alice (if there are only two characters, "of Alice" could be omitted).
note right of Alice: Add a note shape on the right of Alice.
note over Alice: text3 Add a note shape displayed over Alice.
note over Alice, Bob: Add a note shape displayed over Alice and Bob.
note over Bob, Alice: This is an example of a long note. End note Add a note shape with multiple-lined notes, displayed over Alice and Bob.
Grouping alt successful case: Bob -> Alice: data accepted; else some kind of failure. Bob -> Alice: data Build a grouping message with "alt" (alternative) and "else" to show different situations. SupportedMarkup3.png
opt text1

Alice -> Bob: text2


Build a grouping message with the keyword "opt."

You can change "opt" to other keywords as well. We support four key words in this pattern:

  • - opt (means "optional")
  • - par (means "parallel")
  • - loop
  • - critical

Note: These four keywords don't support "else." Only the keyword "alt" can be paired with "else."

Alias participant A as Alice Give participants aliases so you can write faster.
participant A as "Alice Jones" Put quotation marks around alias to give participant an alias longer than one word.
Comments 'comment text Single line comment
/' comment text '/ Multiple line comment

Don’t worry if your sequence diagram isn’t perfect on the first try. You can still edit the markup of a diagram you have already built, as long as you have not manually adjusted or ungrouped the diagram on the canvas.

Simply click on the diagram, and the sequence markup dialogue will appear on the left side of the editor.

Select the sequence diagram, and use the Properties bar at the top of the editor to style your diagram. If you would like to style individual blocks/elements on your diagram, you must first ungroup the diagram. Select the diagram, right-click, and select “Ungroup.”

Note: If you ungroup your diagram, you will not be able to edit the markup again.

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