# ZenUML Sequence Diagrams in Confluence: Copy-Paste Guide

September 24, 2026 ·

<!-- -->

4 min read

[NGPilot](https://ngpilot.com)

Sequence diagrams die in Confluence in one of two ways: someone draws one in a diagramming tool, exports a PNG, pastes it into a page — and three sprints later the flow has changed but the image has not. Or someone writes the flow as prose ("the client calls the order service, and if payment is approved…"), which is accurate but impossible to read under time pressure.

ZenUML splits the difference: the diagram *is* code, so it edits like code and renders like a diagram — branches, error paths, and parallel work included. This guide shows the syntax with copy-paste examples you can drop into Confluence today.

**Quick answer:** To create ZenUML sequence diagrams in Confluence, install [Enhanced Markdown for Confluence](https://marketplace.atlassian.com/apps/1237026/enhanced-markdown-for-confluence) and use a ` ```zenuml ` fence in its Markdown macro. ZenUML renders UML sequence diagrams with real control flow — `if/else`, `try/catch`, `par`, `while` — in the browser, fully inside Confluence. Free for up to 10 users.

## The First Diagram — Checkout with a Branch[​](#the-first-diagram--checkout-with-a-branch "Direct link to The First Diagram — Checkout with a Branch")

Paste this into a ` ```zenuml ` fence:

````
```zenuml

participant User

participant Checkout

participant PaymentProvider

User->Checkout: submit order

Checkout->PaymentProvider: charge card

if (payment approved) {

  Checkout-->User: confirmation page

} else {

  Checkout->PaymentProvider: retry with backoff

  Checkout-->User: "will confirm by email"

}

```
````

![ZenUML checkout sequence with if/else branch rendered in Confluence](data:image/svg+xml;base64,<svg id="blog-svg-c5i9vjo3ao" width="100%" xmlns="http://www.w3.org/2000/svg" style="background-color: white; max-width: 589.5px;" viewBox="0 0 589.5 441" role="graphics-document document" aria-roledescription="zenuml"><defs>
  <style>
  .frame-border-outer { fill: #666; }
  .frame-border-inner { fill: #ffffff; }
  .frame-header-bg { fill: #ffffff; }
  .frame-header-line { stroke: #666; stroke-width: 1; shape-rendering: crispEdges; }
  .frame-title { font-family: Helvetica, Verdana, serif; font-size: 16px; font-weight: 600; fill: #222; }
  .participant-box { fill: #ffffff; stroke: #666; stroke-width: 2; }
  .participant-label { font-family: Helvetica, Verdana, serif; font-size: 16px; fill: #222; }
  .participant-icon { color: #222; }
  .participant-icon [fill="currentColor"]:not([stroke]) { stroke: #666; stroke-width: 1; }
  .lifeline { stroke: #666; stroke-width: 1; }
  .message-line { stroke: #000; stroke-width: 2; shape-rendering: crispEdges; }
  .message-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #222; }
  .arrow-head { fill: #000; stroke: #000; stroke-width: 2; }
  .arrow-open { fill: none; }
  .occurrence { fill: #dedede; stroke: #666; stroke-width: 2; shape-rendering: crispEdges; }
  .fragment-border { fill: none; stroke: #666; stroke-width: 1; shape-rendering: crispEdges; }
  .fragment-header { fill: #dedede; fill-opacity: 0.498; stroke: none; shape-rendering: crispEdges; }
  .fragment-label { font-family: Helvetica, Verdana, serif; font-size: 14px; font-weight: 600; fill: #000; }
  .fragment-condition { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #000; }
  .fragment-separator { stroke: #e5e7eb; stroke-width: 1; shape-rendering: crispEdges; }
  .fragment-section-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #000; }
  .return-line { stroke: #000; stroke-width: 2; stroke-dasharray: 6,4; shape-rendering: crispEdges; }
  .return-arrow { stroke: #000; stroke-width: 2; fill: none; }
  .return-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #222; }
  .return-icon { fill: #222; }
  .divider-line { stroke: #aaaa33; stroke-width: 1; }
  .divider-bg { fill: #fff5ad; stroke: #aaaa33; stroke-width: 1; }
  .divider-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #333; }
  .comment-text { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #333; opacity: 0.5; }
  .seq-number { font-family: Helvetica, Verdana, serif; font-size: 12px; font-weight: 100; fill: #6b7280; }
  .group-outline { fill: none; stroke: #666; }
  .group-title-bg { fill: #ffffff; stroke: none; }
  .group-title-text { font-family: Helvetica, Verdana, serif; font-size: 13px; font-weight: 400; fill: #222; }
</style>
</defs>
<rect class="frame-border-outer" x="0" y="0" width="589.5" height="441" rx="4" fill="#666"></rect>
<rect class="frame-border-inner" x="1" y="1" width="587.5" height="439" rx="3" fill="#fff"></rect>
<line class="frame-header-line" x1="1" y1="33.5" x2="588.5" y2="33.5"></line>

<g transform="translate(21, 34)">
<line x1="50.5" y1="68" x2="50.5" y2="406" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="150.5" y1="68" x2="150.5" y2="406" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="330.5" y1="68" x2="330.5" y2="406" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="476.5" y1="68" x2="476.5" y2="406" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<g class="participant" data-participant="participant">
  <rect x="6.08984375" y="29" width="87.8203125" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="50" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">participant</text>
</g>
<g class="participant" data-participant="User">
  <rect x="111" y="29" width="78" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="150" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">User</text>
</g>
<g class="participant" data-participant="Checkout">
  <rect x="289.203125" y="29" width="81.59375" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="330" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">Checkout</text>
</g>
<g class="participant" data-participant="PaymentProvider">
  <rect x="407.640625" y="29" width="136.71875" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="476" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">PaymentProvider</text>
</g>
<g class="message">
  <line x1="151" y1="87" x2="330" y2="87" class="message-line"></line>
  <svg x="323" y="82" width="7" height="10" viewBox="0 0 7 9" overflow="visible" class="arrow-head arrow-open">
    <g>
      <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" stroke-width="2" fill="none"></path>
    </g>
  </svg>
  <text x="237" y="84" text-anchor="middle" class="message-label">submit order</text>
  <text x="147" y="84" text-anchor="end" class="seq-number">1</text>
</g>
<g class="message">
  <line x1="331" y1="119" x2="476" y2="119" class="message-line"></line>
  <svg x="469" y="114" width="7" height="10" viewBox="0 0 7 9" overflow="visible" class="arrow-head arrow-open">
    <g>
      <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" stroke-width="2" fill="none"></path>
    </g>
  </svg>
  <text x="400" y="116" text-anchor="middle" class="message-label">charge card</text>
  <text x="327" y="116" text-anchor="end" class="seq-number">2</text>
</g>
<g class="message">
  <line x1="331" y1="290" x2="476" y2="290" class="message-line"></line>
  <svg x="469" y="285" width="7" height="10" viewBox="0 0 7 9" overflow="visible" class="arrow-head arrow-open">
    <g>
      <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" stroke-width="2" fill="none"></path>
    </g>
  </svg>
  <text x="400" y="287" text-anchor="middle" class="message-label">retry with backoff</text>
  <text x="327" y="287" text-anchor="end" class="seq-number">3.2</text>
</g>
<g class="return">
  <line x1="330" y1="213" x2="151" y2="213" class="return-line"></line>
  <polyline points="156.15,209.75 151,213 156.15,216.25" fill="none" stroke-linecap="round" class="return-arrow"></polyline>
  <text x="244" y="210" text-anchor="middle" class="return-label">confirmation page</text>
  <text x="147" y="210" text-anchor="end" class="seq-number">3.1</text>
</g>
<g class="return">
  <line x1="330" y1="322" x2="151" y2="322" class="return-line"></line>
  <polyline points="156.15,318.75 151,322 156.15,325.25" fill="none" stroke-linecap="round" class="return-arrow"></polyline>
  <text x="244" y="319" text-anchor="middle" class="return-label">"will confirm by email"</text>
  <text x="147" y="319" text-anchor="end" class="seq-number">3.3</text>
</g>
<g class="fragment fragment-alt">
  <rect x="90.5" y="136.5" width="466.5" height="213" rx="4" class="fragment-border"></rect>
  <rect x="91" y="137" width="465.5" height="25" class="fragment-header"></rect>
  <svg x="95" y="137" width="20" height="24" viewBox="0 0 24 24" fill="none">
      <path d="M12 8L20 12L12 16L4 12L12 8Z" stroke="#000" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"></path>
    </svg>
  <text x="117" y="149" dominant-baseline="central" class="fragment-label">Alt</text>
  <text x="87" y="145" text-anchor="end" dominant-baseline="central" class="seq-number">3</text>
  <g><text x="91" y="177" class="fragment-condition">[</text><text x="98.89" y="177" class="fragment-condition" opacity="0.65">payment approved</text><text x="218.85484375" y="177" class="fragment-condition">]</text></g>
  <line x1="91" y1="238.5" x2="556.5" y2="238.5" class="fragment-separator"></line>
  <text x="95" y="254" class="fragment-section-label">[else]</text>
</g>
</g></svg>)

What you get for six lines of logic: labeled participants, a synchronous call (`->`), returns (`-->`), and an `if/else` rendered as proper frames — auto-numbered, so a reader can follow the request/response pairing without guessing.

## The Syntax in One Table[​](#the-syntax-in-one-table "Direct link to The Syntax in One Table")

| Token                      | Meaning                         | Example                             |
| -------------------------- | ------------------------------- | ----------------------------------- |
| `participant X`            | Declare a participant           | `participant Checkout`              |
| `@Actor X` / `@Database X` | Annotate the participant's role | `@Database PaymentDB`               |
| `A->B: msg`                | Synchronous call                | `Checkout->PaymentProvider: charge` |
| `A-->B: msg`               | Return / reply                  | `Checkout-->User: 201 Created`      |
| `if (x) { } else { }`      | Branch frames                   | `if (approved) { ... }`             |
| `while (x) { }`            | Loop frame                      | `while (retries left) { ... }`      |
| `par { } and { }`          | Parallel blocks                 | fan-out and join                    |
| `try { } catch (E) { }`    | Error path                      | reservation failure                 |

The annotators are worth adopting on day one: `@Actor Alice` and `@Database OrdersDB` change the participant's icon, so a reader sees who is a human and who is a store before reading a single message.

## Error Paths as First-Class Citizens[​](#error-paths-as-first-class-citizens "Direct link to Error Paths as First-Class Citizens")

The example that sells most teams: an order flow where reservation can fail. In a drawing tool this is a second diagram to maintain; in ZenUML it is four lines:

````
```zenuml

participant Client

participant OrderService

participant InventoryService

Client->OrderService: POST /orders

OrderService->InventoryService: reserve(SKU-991, qty=2)

try {

  InventoryService-->OrderService: reservation #R-4821

  OrderService-->Client: 201 Created, order #A-1088

} catch (OutOfStockError) {

  OrderService-->Client: 409 Conflict, "insufficient stock"

}

```
````

![ZenUML try/catch sequence diagram for an inventory reservation](data:image/svg+xml;base64,<svg id="blog-svg-k7ashio5pkp" width="100%" xmlns="http://www.w3.org/2000/svg" style="background-color: white; max-width: 702.5px;" viewBox="0 0 702.5 421" role="graphics-document document" aria-roledescription="zenuml"><defs>
  <style>
  .frame-border-outer { fill: #666; }
  .frame-border-inner { fill: #ffffff; }
  .frame-header-bg { fill: #ffffff; }
  .frame-header-line { stroke: #666; stroke-width: 1; shape-rendering: crispEdges; }
  .frame-title { font-family: Helvetica, Verdana, serif; font-size: 16px; font-weight: 600; fill: #222; }
  .participant-box { fill: #ffffff; stroke: #666; stroke-width: 2; }
  .participant-label { font-family: Helvetica, Verdana, serif; font-size: 16px; fill: #222; }
  .participant-icon { color: #222; }
  .participant-icon [fill="currentColor"]:not([stroke]) { stroke: #666; stroke-width: 1; }
  .lifeline { stroke: #666; stroke-width: 1; }
  .message-line { stroke: #000; stroke-width: 2; shape-rendering: crispEdges; }
  .message-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #222; }
  .arrow-head { fill: #000; stroke: #000; stroke-width: 2; }
  .arrow-open { fill: none; }
  .occurrence { fill: #dedede; stroke: #666; stroke-width: 2; shape-rendering: crispEdges; }
  .fragment-border { fill: none; stroke: #666; stroke-width: 1; shape-rendering: crispEdges; }
  .fragment-header { fill: #dedede; fill-opacity: 0.498; stroke: none; shape-rendering: crispEdges; }
  .fragment-label { font-family: Helvetica, Verdana, serif; font-size: 14px; font-weight: 600; fill: #000; }
  .fragment-condition { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #000; }
  .fragment-separator { stroke: #e5e7eb; stroke-width: 1; shape-rendering: crispEdges; }
  .fragment-section-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #000; }
  .return-line { stroke: #000; stroke-width: 2; stroke-dasharray: 6,4; shape-rendering: crispEdges; }
  .return-arrow { stroke: #000; stroke-width: 2; fill: none; }
  .return-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #222; }
  .return-icon { fill: #222; }
  .divider-line { stroke: #aaaa33; stroke-width: 1; }
  .divider-bg { fill: #fff5ad; stroke: #aaaa33; stroke-width: 1; }
  .divider-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #333; }
  .comment-text { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #333; opacity: 0.5; }
  .seq-number { font-family: Helvetica, Verdana, serif; font-size: 12px; font-weight: 100; fill: #6b7280; }
  .group-outline { fill: none; stroke: #666; }
  .group-title-bg { fill: #ffffff; stroke: none; }
  .group-title-text { font-family: Helvetica, Verdana, serif; font-size: 13px; font-weight: 400; fill: #222; }
</style>
</defs>
<rect class="frame-border-outer" x="0" y="0" width="702.5" height="421" rx="4" fill="#666"></rect>
<rect class="frame-border-inner" x="1" y="1" width="700.5" height="419" rx="3" fill="#fff"></rect>
<line class="frame-header-line" x1="1" y1="33.5" x2="701.5" y2="33.5"></line>

<g transform="translate(21, 34)">
<line x1="50.5" y1="68" x2="50.5" y2="386" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="150.5" y1="68" x2="150.5" y2="386" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="393.5" y1="68" x2="393.5" y2="386" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="591.5" y1="68" x2="591.5" y2="386" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<g class="participant" data-participant="participant">
  <rect x="6.08984375" y="29" width="87.8203125" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="50" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">participant</text>
</g>
<g class="participant" data-participant="Client">
  <rect x="111" y="29" width="78" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="150" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">Client</text>
</g>
<g class="participant" data-participant="OrderService">
  <rect x="338.875" y="29" width="108.25" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="393" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">OrderService</text>
</g>
<g class="participant" data-participant="InventoryService">
  <rect x="524.41796875" y="29" width="133.1640625" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="591" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">InventoryService</text>
</g>
<g class="message">
  <line x1="151" y1="87" x2="393" y2="87" class="message-line"></line>
  <svg x="386" y="82" width="7" height="10" viewBox="0 0 7 9" overflow="visible" class="arrow-head arrow-open">
    <g>
      <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" stroke-width="2" fill="none"></path>
    </g>
  </svg>
  <text x="268.5" y="84" text-anchor="middle" class="message-label">POST /orders</text>
  <text x="147" y="84" text-anchor="end" class="seq-number">1</text>
</g>
<g class="message">
  <line x1="394" y1="119" x2="591" y2="119" class="message-line"></line>
  <svg x="584" y="114" width="7" height="10" viewBox="0 0 7 9" overflow="visible" class="arrow-head arrow-open">
    <g>
      <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" stroke-width="2" fill="none"></path>
    </g>
  </svg>
  <text x="489" y="116" text-anchor="middle" class="message-label">reserve(SKU-991, qty=2)</text>
  <text x="390" y="116" text-anchor="end" class="seq-number">2</text>
</g>
<g class="return">
  <line x1="591" y1="193" x2="394" y2="193" class="return-line"></line>
  <polyline points="399.15,189.75 394,193 399.15,196.25" fill="none" stroke-linecap="round" class="return-arrow"></polyline>
  <text x="496" y="190" text-anchor="middle" class="return-label">reservation #R-4821</text>
  <text x="390" y="190" text-anchor="end" class="seq-number">3.1</text>
</g>
<g class="return">
  <line x1="393" y1="225" x2="151" y2="225" class="return-line"></line>
  <polyline points="156.15,221.75 151,225 156.15,228.25" fill="none" stroke-linecap="round" class="return-arrow"></polyline>
  <text x="275.5" y="222" text-anchor="middle" class="return-label">201 Created,order #A-1088</text>
  <text x="147" y="222" text-anchor="end" class="seq-number">3.2</text>
</g>
<g class="return">
  <line x1="393" y1="302" x2="151" y2="302" class="return-line"></line>
  <polyline points="156.15,298.75 151,302 156.15,305.25" fill="none" stroke-linecap="round" class="return-arrow"></polyline>
  <text x="275.5" y="299" text-anchor="middle" class="return-label">409 Conflict,"insufficient stock"</text>
  <text x="147" y="299" text-anchor="end" class="seq-number">3.3</text>
</g>
<g class="fragment fragment-tcf">
  <rect x="90.5" y="136.5" width="579.5" height="193" rx="4" class="fragment-border"></rect>
  <rect x="91" y="137" width="578.5" height="25" class="fragment-header"></rect>
  <svg x="95" y="137" width="20" height="24" viewBox="0 0 76 76" fill="#000" stroke="none">
      <path d="M 26,22.0001L 27,21.9998L 27,27L 26.0001,27.0003C 23.2386,27.0003 21.0001,29.2389 21.0001,32.0003L 21,46.0002C 21,48.7616 23.2386,51.0002 25.9999,51.0002L 27,51.0002L 27,47L 33.75,53.5L 27,60L 27,56L 26,56C 20.4771,56 16,51.5229 16,46L 16,32.0001C 16,26.4773 20.4771,22.0001 26,22.0001 Z M 33,27L 59,27L 59,32L 33,32L 33,27 Z M 36,35L 59,35L 59,40L 36,40L 36,35 Z M 33,43L 59,43L 59,48L 33,48L 33,43 Z"></path>
    </svg>
  <text x="117" y="149" dominant-baseline="central" class="fragment-label">Try</text>
  <text x="87" y="145" text-anchor="end" dominant-baseline="central" class="seq-number">3</text>
  <line x1="91" y1="250.5" x2="669.5" y2="250.5" class="fragment-separator"></line>
  <g opacity="0.65"><rect x="91" y="251" width="152.9306640625" height="20" fill="#fff"></rect><text x="95" y="266" class="fragment-section-label" fill="#222">catch</text><text x="136.4619140625" y="266" class="fragment-section-label" fill="#222">OutOfStockError</text></g>
</g>
</g></svg>)

The happy path and the failure path live in the same block of text, review together in a PR, and — the actual point — get updated in the same commit when the API contract changes.

## Parallel Work with par/and[​](#parallel-work-with-parand "Direct link to Parallel Work with par/and")

Batch jobs and fan-outs read cleanly with `par`:

````
```zenuml

participant Scheduler

participant BillingService

participant EmailService

Scheduler->BillingService: run monthly invoices

par {

  BillingService->BillingService: render PDF statements

}

and {

  BillingService->EmailService: queue invoice emails

}

BillingService-->Scheduler: 1,204 invoices, 3 failures

```
````

![ZenUML par block for parallel billing work](data:image/svg+xml;base64,<svg id="blog-svg-ojg82rp6f19" width="100%" xmlns="http://www.w3.org/2000/svg" style="background-color: white; max-width: 730.5px;" viewBox="0 0 730.5 436" role="graphics-document document" aria-roledescription="zenuml"><defs>
  <style>
  .frame-border-outer { fill: #666; }
  .frame-border-inner { fill: #ffffff; }
  .frame-header-bg { fill: #ffffff; }
  .frame-header-line { stroke: #666; stroke-width: 1; shape-rendering: crispEdges; }
  .frame-title { font-family: Helvetica, Verdana, serif; font-size: 16px; font-weight: 600; fill: #222; }
  .participant-box { fill: #ffffff; stroke: #666; stroke-width: 2; }
  .participant-label { font-family: Helvetica, Verdana, serif; font-size: 16px; fill: #222; }
  .participant-icon { color: #222; }
  .participant-icon [fill="currentColor"]:not([stroke]) { stroke: #666; stroke-width: 1; }
  .lifeline { stroke: #666; stroke-width: 1; }
  .message-line { stroke: #000; stroke-width: 2; shape-rendering: crispEdges; }
  .message-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #222; }
  .arrow-head { fill: #000; stroke: #000; stroke-width: 2; }
  .arrow-open { fill: none; }
  .occurrence { fill: #dedede; stroke: #666; stroke-width: 2; shape-rendering: crispEdges; }
  .fragment-border { fill: none; stroke: #666; stroke-width: 1; shape-rendering: crispEdges; }
  .fragment-header { fill: #dedede; fill-opacity: 0.498; stroke: none; shape-rendering: crispEdges; }
  .fragment-label { font-family: Helvetica, Verdana, serif; font-size: 14px; font-weight: 600; fill: #000; }
  .fragment-condition { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #000; }
  .fragment-separator { stroke: #e5e7eb; stroke-width: 1; shape-rendering: crispEdges; }
  .fragment-section-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #000; }
  .return-line { stroke: #000; stroke-width: 2; stroke-dasharray: 6,4; shape-rendering: crispEdges; }
  .return-arrow { stroke: #000; stroke-width: 2; fill: none; }
  .return-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #222; }
  .return-icon { fill: #222; }
  .divider-line { stroke: #aaaa33; stroke-width: 1; }
  .divider-bg { fill: #fff5ad; stroke: #aaaa33; stroke-width: 1; }
  .divider-label { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #333; }
  .comment-text { font-family: Helvetica, Verdana, serif; font-size: 14px; fill: #333; opacity: 0.5; }
  .seq-number { font-family: Helvetica, Verdana, serif; font-size: 12px; font-weight: 100; fill: #6b7280; }
  .group-outline { fill: none; stroke: #666; }
  .group-title-bg { fill: #ffffff; stroke: none; }
  .group-title-text { font-family: Helvetica, Verdana, serif; font-size: 13px; font-weight: 400; fill: #222; }
</style>
</defs>
<rect class="frame-border-outer" x="0" y="0" width="730.5" height="436" rx="4" fill="#666"></rect>
<rect class="frame-border-inner" x="1" y="1" width="728.5" height="434" rx="3" fill="#fff"></rect>
<line class="frame-header-line" x1="1" y1="33.5" x2="729.5" y2="33.5"></line>

<g transform="translate(21, 34)">
<line x1="56" y1="68" x2="56" y2="401" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="161.5" y1="68" x2="161.5" y2="401" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="261.5" y1="68" x2="261.5" y2="401" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="458.5" y1="68" x2="458.5" y2="401" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<line x1="632.5" y1="68" x2="632.5" y2="401" class="lifeline" stroke-dasharray="5,5" stroke-dashoffset="5" shape-rendering="crispEdges"></line>
<g class="participant participant-starter" data-participant="_STARTER_">
  <rect x="16.5" y="29" width="78" height="38" rx="3" class="participant-box"></rect>
  <g class="participant-icon" transform="translate(41.5, 36) scale(1)" fill="none">
    <g>
    <path d="M15.5489 4.19771C15.5489 5.18773 15.1485 6.13721 14.4358 6.83726C13.7231 7.53731 12.7565 7.93058 11.7486 7.93058C10.7407 7.93058 9.77403 7.53731 9.06133 6.83726C8.34863 6.13721 7.94824 5.18773 7.94824 4.19771C7.94824 3.20768 8.34863 2.25822 9.06133 1.55818C9.77403 0.858126 10.7407 0.464844 11.7486 0.464844C12.7565 0.464844 13.7231 0.858126 14.4358 1.55818C15.1485 2.25822 15.5489 3.20768 15.5489 4.19771Z" stroke="currentColor"></path>
    <path d="M6.54883 11.2152L17.2025 11.2073M11.7471 8.06641V19.5806V8.06641ZM11.7471 19.4385L6.79789 23.5738L11.7471 19.4385ZM11.7551 19.4385L17.1864 23.3055L11.7551 19.4385Z" stroke="currentColor"></path>
  </g>
  </g>
</g>
<g class="participant" data-participant="participant">
  <rect x="117.08984375" y="29" width="87.8203125" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="161" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">participant</text>
</g>
<g class="participant" data-participant="Scheduler">
  <rect x="217.9765625" y="29" width="86.046875" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="261" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">Scheduler</text>
</g>
<g class="participant" data-participant="BillingService">
  <rect x="402.98046875" y="29" width="110.0390625" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="458" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">BillingService</text>
</g>
<g class="participant" data-participant="EmailService">
  <rect x="578.3203125" y="29" width="107.359375" height="38" rx="3" class="participant-box"></rect>
  
  
  
  <text x="632" y="47.75" text-anchor="middle" dominant-baseline="central" class="participant-label">EmailService</text>
</g>
<rect x="49.5" y="262" width="13" height="50" rx="1" class="occurrence" data-participant="_STARTER_"></rect>
<g class="message">
  <line x1="262" y1="87" x2="458" y2="87" class="message-line"></line>
  <svg x="451" y="82" width="7" height="10" viewBox="0 0 7 9" overflow="visible" class="arrow-head arrow-open">
    <g>
      <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" stroke-width="2" fill="none"></path>
    </g>
  </svg>
  <text x="356.5" y="84" text-anchor="middle" class="message-label">run monthly invoices</text>
  <text x="258" y="84" text-anchor="end" class="seq-number">1</text>
</g>
<g class="message">
  <line x1="459" y1="294" x2="632" y2="294" class="message-line"></line>
  <svg x="625" y="289" width="7" height="10" viewBox="0 0 7 9" overflow="visible" class="arrow-head arrow-open">
    <g>
      <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" stroke-width="2" fill="none"></path>
    </g>
  </svg>
  <text x="542" y="291" text-anchor="middle" class="message-label">queue invoice emails</text>
  <text x="455" y="291" text-anchor="end" class="seq-number">3.1</text>
</g>
<g class="message self-call">
  <svg x="459" y="166" width="30" height="24">
    <path d="M0,2 L26,2 Q28,2 28,4 L28,13 Q28,15 26,15 L1,15" fill="none" stroke="#000" stroke-width="2"></path>
    <g transform="translate(0, 10)">
      <svg height="10" width="7" viewBox="0 0 7 9">
        <g transform="scale(-1, 1) translate(-7, 0)">
          <path d="M1 1.25 L6.15 4.5 L1 7.75" stroke="#000" stroke-linecap="round" fill="none" stroke-width="2"></path>
        </g>
      </svg>
    </g>
  </svg>
  <text x="464" y="161" text-anchor="start" class="message-label">render PDF statements</text>
  <text x="455" y="158" text-anchor="end" class="seq-number">2.1</text>
</g>
<g class="message self-call">
  <svg x="56.5" y="247" width="30" height="24">
    <path d="M0,2 L26,2 Q28,2 28,4 L28,13 Q28,15 26,15 L14,15" fill="none" stroke="#000" stroke-width="2"></path>
    <g transform="translate(7, 10)">
      <svg height="10" width="7" viewBox="0 0 7 9">
        <g transform="scale(-1, 1) translate(-7, 0)">
          <path d="M1 1.25 L6.15 4.5 L1 7.75 Z" stroke="#000" stroke-linecap="round" fill="#000" stroke-width="2"></path>
        </g>
      </svg>
    </g>
  </svg>
  <text x="61.5" y="245" text-anchor="start" class="message-label">and</text>
  <text x="52.5" y="245" text-anchor="end" class="seq-number">3</text>
</g>
<g class="return">
  <line x1="458" y1="344" x2="262" y2="344" class="return-line"></line>
  <polyline points="267.15,340.75 262,344 267.15,347.25" fill="none" stroke-linecap="round" class="return-arrow"></polyline>
  <text x="363.5" y="341" text-anchor="middle" class="return-label">1,204 invoices,3 failures</text>
  <text x="258" y="341" text-anchor="end" class="seq-number">4</text>
</g>
<g class="fragment fragment-par">
  <rect x="-9.5" y="104.5" width="642" height="112" rx="4" class="fragment-border"></rect>
  <rect x="-9" y="105" width="641" height="25" class="fragment-header"></rect>
  <svg x="-5" y="105" width="20" height="24" viewBox="0 0 24 24" fill="none">
      <path d="M5 10H19" stroke="#000" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"></path>
      <path d="M5 14H19" stroke="#000" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"></path>
    </svg>
  <text x="17" y="117" dominant-baseline="central" class="fragment-label">Par</text>
  <text x="-13" y="113" text-anchor="end" dominant-baseline="central" class="seq-number">2</text>
</g>
</g></svg>)

`par` and `and` nest inside `if` and `try` too, so a real integration flow — branches, retries, parallel calls — stays one readable diagram instead of three screenshots stitched together.

## ZenUML or Mermaid sequenceDiagram?[​](#zenuml-or-mermaid-sequencediagram "Direct link to ZenUML or Mermaid sequenceDiagram?")

Both render in the same macro; they optimize for different moments:

| Situation                                                 | Reach for                            |
| --------------------------------------------------------- | ------------------------------------ |
| Simple request/response flow, documentation flavor        | Mermaid `sequenceDiagram`            |
| Business logic with branches and error paths              | ZenUML                               |
| Diagram also lives in a GitHub README                     | Mermaid (GitHub renders it natively) |
| Spec where the diagram must match the code's control flow | ZenUML                               |

Install [Enhanced Markdown for Confluence](https://marketplace.atlassian.com/apps/1237026/enhanced-markdown-for-confluence), paste the checkout example into a ` ```zenuml ` fence, and watch the branch render while you type. Free for up to 10 users.

## Related Guides[​](#related-guides "Direct link to Related Guides")

* [Create Mermaid Diagrams in Confluence](/blog/create-mermaid-diagrams-confluence.md) — the same macro's full diagram family
* [Mermaid Sequence Diagrams in Confluence](/blog/mermaid-api-sequence-diagram-confluence.md) — the `sequenceDiagram` route for simpler flows
* [How to Write Markdown in Confluence](/blog/how-to-write-markdown-in-confluence.md) — the base syntax everything lives in

## Related guides

* [How to Create Mermaid Diagrams in Jira](/blog/how-to-create-mermaid-diagrams-jira.md)
* [Export Jira Issues to Excel or CSV](/blog/export-jira-issues-to-excel.md)
* [Bulk Download Jira Attachments](/blog/bulk-download-jira-attachments.md)
* [How to Migrate Confluence Content](/blog/how-to-migrate-confluence-content.md)
* [How to Add a Block Quote in Confluence](/blog/block-quote-confluence.md)

Explore NGPILOT[Browse Solutions](/solutions.md)[All Apps](/apps.md)[Atlassian Marketplace →](https://marketplace.atlassian.com/vendors/1226848/?utm_source=ngpilot.com\&utm_medium=blog\&utm_campaign=hub-links)

**Tags:**

* [confluence](/blog/tags/confluence.md)
* [zenuml](/blog/tags/zenuml.md)
* [sequence-diagram](/blog/tags/sequence-diagram.md)
* [uml](/blog/tags/uml.md)
* [mermaid](/blog/tags/mermaid.md)
* [markdown](/blog/tags/markdown.md)
* [how-to](/blog/tags/how-to.md)
* [engineering](/blog/tags/engineering.md)