Alice->Bob: Authentication Request note right of Bob: Bob thinks about it Bob->Alice: Authentication Response Alice->Bob: Do something Alice->John: Yo note left of John: Hey alt text1 A->B: text else text2 A->B: text end A-->B: text A->A: text
Just came across this little gem while trying to look for a cloud-based tool to create UML diagrams. Pretty darn cool!
You can create a Sequence diagram just by typing the relationships between the entities and it gets rendered automatically.
Check them out.