Mermaid Diagram Export

FlowOrchestrator.Core ships with a one-line exporter that converts a flow's manifest into a Mermaid flowchart definition. The output is plain text that renders directly in any Markdown surface that understands Mermaid — GitHub READMEs and PRs, Notion, Obsidian, Confluence, GitLab, dev.to — without spinning up the dashboard or any other process.

Quick start

using FlowOrchestrator.Core.Diagnostics;

var flow = new OrderFulfillmentFlow();
Console.WriteLine(flow.ToMermaid());

The same extension is available on FlowManifest directly when you hold the manifest without a flow definition wrapper.

Options

MermaidExportOptions exposes four knobs:

Option	Default	Description
`Direction`	`TD`	Mermaid direction header. `TD`, `LR`, `BT`, `RL`.
`IncludeTriggers`	`true`	Emits one node per trigger and connects each to the entry steps.
`ShowStepTypes`	`true`	Renders the handler `Type` as italic text below each step key.
`ApplyStyling`	`true`	Adds `classDef` blocks so triggers, entry, polling, and loop steps differ.

Worked examples

1. Linear flow

new FlowManifest
{
    Triggers = { ["manual"] = new() { Type = TriggerType.Manual } },
    Steps =
    {
        ["a"] = new() { Type = "TypeA" },
        ["b"] = new() { Type = "TypeB", RunAfter = { ["a"] = [StepStatus.Succeeded] } },
        ["c"] = new() { Type = "TypeC", RunAfter = { ["b"] = [StepStatus.Succeeded] } }
    }
}
.ToMermaid();

flowchart TD
    classDef trigger fill:#e1f5ff,stroke:#0288d1
    classDef entry fill:#c8e6c9,stroke:#388e3c
    classDef polling fill:#fff9c4,stroke:#f57f17
    classDef loop fill:#f3e5f5,stroke:#7b1fa2

    T_manual["⚡ manual<br/>Manual"]:::trigger
    a["a<br/><i>TypeA</i>"]:::entry
    b["b<br/><i>TypeB</i>"]
    c["c<br/><i>TypeC</i>"]

    T_manual --> a
    a -- Succeeded --> b
    b -- Succeeded --> c

2. Fan-out / fan-in

A single root branches into three workers that join at a single leaf.

flowchart TD
    root["root"]:::entry
    a["a"]
    b["b"]
    c["c"]
    join["join"]

    root -- Succeeded --> a
    root -- Succeeded --> b
    root -- Succeeded --> c
    a -- Succeeded --> join
    b -- Succeeded --> join
    c -- Succeeded --> join

3. Polling step

When a step's Inputs carries pollEnabled = true, the exporter applies the polling class so it stands out from regular steps.

flowchart TD
    fetch["fetch_orders"]:::entry
    submit["submit_to_wms<br/><i>CallExternalApi</i>"]:::polling

    fetch -- Succeeded --> submit

4. ForEach loop

LoopStepMetadata becomes a Mermaid subgraph containing the child steps.

flowchart TD
    fetch["fetch_orders"]:::entry
    process_each["process_each_orders"]:::loop
    fetch -- Succeeded --> process_each

    subgraph subgraph_process_each["🔁 process_each_orders (ForEach)"]
        validate["validate"]
    end

    process_each --> subgraph_process_each

Using it from the dashboard

Open any flow's detail page, switch to the Mermaid tab, and click Copy Mermaid. The same content is also available via the REST endpoint:

GET /flows/api/flows/{id}/mermaid
Accept: text/plain

Using it from CI

The sample app accepts a --export-mermaid <flowId|flowName> flag that prints the diagram and exits without starting the web host. Wire this into a CI job that comments the new diagram on a pull request whenever a manifest changes:

dotnet run --project samples/FlowOrchestrator.SampleApp -- \
    --export-mermaid OrderFulfillmentFlow > order-fulfillment.mmd

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