Design systems the way they happen.

eventline documentation

Design systems the way they happen.

eventline is a small notation for commands, events and views, built on Event Modeling and Dynamic Consistency Boundaries. Write a model, check it, and draw it.

Open the playgroundRead the language reference

One decision, six lines

user -> postTweet(content, media?) in UserTimeline(userId)
on [user-authenticated(userId)]
  --[content.length > 280]--> [tweet-rejected]
  --[default]--> [
    tweet-created { userId, content, media, createdAt: clock.wall() }
  ]

Open in playground

Commands decideSomeone asks for something. The guards on its edges choose what is recorded.Events rememberWhat happened, as a fact. Events are all that is stored.Views answerA fold over events that answers a question without asking the command.Policies reactWatch an event, issue the next command.

Start from what you need.

1. I am new to Event ModelingEvent storming, Event Modeling and DCBThinking guide
2. I want to learn the notationLanguage referenceWorked examples
3. I have an interview coming upLanguage reference, sections 2 and 5Interview simulation: rate limiter
4. I want to review a model I wroteThinking guideThe checklist in the language reference
5. I need to declare actors or contextActorsSystem context
6. I want to see a whole systemDesign Twitter, DSL to architecture
7. I want to run it on my modelThe CLI
8. I need to look up a termGlossary
9. I want to understand a warningValidation rules
10. I want to change the codeArchitectureContributing