> For the complete documentation index, see [llms.txt](https://www.pranaypourkar.co.in/the-programmers-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.pranaypourkar.co.in/the-programmers-guide/system-design/system-design-methodology/diagrams/uml-diagrams/plantuml/timing-diagram.md).

# Timing Diagram

## About

A Timing Diagram models the state of objects over time, focusing on time-based changes in interactions. It is useful for real-time systems, embedded systems, and protocol modeling.

{% hint style="success" %}
Refer to the official documentation for more details - <https://plantuml.com/timing-diagram>
{% endhint %}

### **Key Elements**

1. **Lifelines (Objects or Entities)**
   * Represented as **horizontal lines**, showing how an entity behaves over time.
2. **States**
   * Represented as **labels** along the timeline (e.g., "Idle", "Processing", "Completed").
3. **Time Axis**
   * Represented as **a horizontal timeline** tracking event occurrences.
4. **State Changes**
   * **Vertical transitions** show state changes at specific time intervals.
5. **Messages**
   * Represented as **arrows** between lifelines.

## 1. Task Execution Over Time

```plant-uml
@startuml
robust "Web Browser" as WB
concise "Web User" as WU

use date format "YY-MM-dd"

@2019/07/02
WU is Idle
WB is Idle

@2019/07/04
WU is Waiting : some note
WB is Processing : some other note

@2019/07/05
WB is Waiting
@enduml
```

<figure><img src="https://3632859567-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FPd6ktrA5pPLsZJktj2fm%2Fuploads%2F8hQocBBZempUSXwXvbX1%2Fplantuml-timing-diagram-1.png?alt=media&amp;token=01444722-9f2a-4d02-a4f3-3b648a4a1fce" alt="" width="265"><figcaption></figcaption></figure>


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