JBZoo / Mermaid-PHP

A powerful PHP library for generating Mermaid diagrams programmatically. Create flowcharts, ER diagrams, class diagrams, and timelines with a fluent, object-oriented API.

Table of Contents

• Installation
• Requirements
• Features
• Quick Start
• Diagram Types
  • Flowcharts/Graphs
  • ER Diagrams
  • Class Diagrams
  • Timeline Diagrams
  • Sequence Diagrams
• Output Formats
• Development
• License
• Related Projects

Installation

Install via Composer:

composer require jbzoo/mermaid-php

Requirements

• PHP 8.3 or higher
• ext-json

Features

✅ Multiple Diagram Types: Flowcharts, ER diagrams, class diagrams, sequence diagrams, and timelines ✅ Fluent API: Intuitive method chaining for building complex diagrams ✅ Multiple Output Formats: Mermaid syntax, HTML with embedded viewer, live editor URLs ✅ Theme Support: Default, forest, dark, and neutral themes ✅ Rich Customization: Nodes, links, relationships, styling, and more ✅ Type Safety: Full PHP type hints and strict typing ✅ Zero Dependencies: Only requires PHP and ext-json

Quick Start

<?php

use JBZoo\MermaidPHP\Graph;
use JBZoo\MermaidPHP\Node;
use JBZoo\MermaidPHP\Link;

// Create a simple flowchart
$graph = new Graph(['title' => 'My Workflow']);
$graph
    ->addNode($start = new Node('start', 'Start', Node::ROUND))
    ->addNode($process = new Node('process', 'Process Data', Node::SQUARE))
    ->addNode($end = new Node('end', 'End', Node::ROUND))
    ->addLink(new Link($start, $process))
    ->addLink(new Link($process, $end));

// Output Mermaid syntax
echo $graph;

// Generate HTML with embedded viewer
echo $graph->renderHtml(['theme' => 'dark']);

// Get live editor URL for debugging
echo $graph->getLiveEditorUrl();

Diagram Types

Flowcharts/Graphs

Create complex flowcharts with nodes, links, and subgraphs:

<?php

use JBZoo\MermaidPHP\Graph;
use JBZoo\MermaidPHP\Link;
use JBZoo\MermaidPHP\Node;
use JBZoo\MermaidPHP\Render;

$graph = (new Graph(['abc_order' => true]))
    ->addSubGraph($subGraph1 = new Graph(['title' => 'Main workflow']))
    ->addSubGraph($subGraph2 = new Graph(['title' => 'Problematic workflow']))
    ->addStyle('linkStyle default interpolate basis');

$subGraph1
    ->addNode($nodeE = new Node('E', 'Result two', Node::SQUARE))
    ->addNode($nodeB = new Node('B', 'Round edge', Node::ROUND))
    ->addNode($nodeA = new Node('A', 'Hard edge', Node::SQUARE))
    ->addNode($nodeC = new Node('C', 'Decision', Node::CIRCLE))
    ->addNode($nodeD = new Node('D', 'Result one', Node::SQUARE))
    ->addLink(new Link($nodeE, $nodeD))
    ->addLink(new Link($nodeB, $nodeC))
    ->addLink(new Link($nodeC, $nodeD, 'A double quote:"'))
    ->addLink(new Link($nodeC, $nodeE, 'A dec char:♥'))
    ->addLink(new Link($nodeA, $nodeB, ' Link text<br>/\\!@#$%^&*()_+><\' " '));

$subGraph2
    ->addNode($alone = new Node('alone', 'Alone'))
    ->addLink(new Link($alone, $nodeC));

echo $graph; // Get result as string (or $graph->__toString(), or (string)$graph)
$htmlCode = $graph->renderHtml([
    'debug'       => true,
    'theme'       => Render::THEME_DARK,
    'title'       => 'Example',
    'show-zoom'   => false,
    'mermaid_url' => 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs',
]); // Get result as HTML code for debugging

echo $graph->getLiveEditorUrl(); // Get link to live editor

Result

Open live editor

graph TB;
    subgraph "Main workflow"
        E["Result two"];
        B("Round edge");
        A["Hard edge"];
        C(("Decision"));
        D["Result one"];
        E-->D;
        B-->C;
        C-->|"A double quote:#quot;"|D;
        C-->|"A dec char:#hearts;"|E;
        A-->|"Link text<br>/\!@#$%^#amp;*()_+><' #quot;"|B;
    end
    subgraph "Problematic workflow"
        alone("Alone");
        alone-->C;
    end
linkStyle default interpolate basis;

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Clickable nodes

Attach a hyperlink (with an optional tooltip and target) to any node; it renders as a Mermaid click directive:

use JBZoo\MermaidPHP\Graph;
use JBZoo\MermaidPHP\Node;

$graph = (new Graph())
    ->addNode($docs = (new Node('D', 'Docs'))
        ->setUrl('https://github.com/JBZoo/Mermaid-PHP')
        ->setTooltip('Open the repository')
        ->setTarget(Node::TARGET_BLANK));

echo $graph;
// graph TB;
//     D("Docs");
//
// click D "https://github.com/JBZoo/Mermaid-PHP" "Open the repository" _blank

setUrl() alone is enough; setTooltip() and setTarget() (Node::TARGET_BLANK, TARGET_SELF, TARGET_PARENT, TARGET_TOP) are optional.

Per-link styles

Give an individual link its own CSS; it renders as a linkStyle <index> ... directive. The index is resolved automatically from the link's position in the whole graph (sub-graphs and abc_order included):

use JBZoo\MermaidPHP\Graph;
use JBZoo\MermaidPHP\Link;
use JBZoo\MermaidPHP\Node;

$graph = (new Graph())
    ->addNode($a = new Node('A'))
    ->addNode($b = new Node('B'))
    ->addLink((new Link($a, $b))->setCss('stroke:blue,stroke-width:4px'));

echo $graph;
// graph TB;
//     A("A");
//     B("B");
//
//     A-->B;
//
// linkStyle 0 stroke:blue,stroke-width:4px;

The same CSS can be passed through the id-based helper: $graph->addLinkByIds('A', 'B', '', Link::ARROW, 'stroke:blue');.

ER Diagrams

Build entity-relationship diagrams for database schemas:

<?php

use JBZoo\MermaidPHP\ERDiagram\Entity\Entity;
use JBZoo\MermaidPHP\ERDiagram\Entity\EntityProperty;
use JBZoo\MermaidPHP\ERDiagram\ERDiagram;
use JBZoo\MermaidPHP\ERDiagram\Relation\ManyToMany;
use JBZoo\MermaidPHP\ERDiagram\Relation\ManyToOne;
use JBZoo\MermaidPHP\ERDiagram\Relation\OneToMany;
use JBZoo\MermaidPHP\ERDiagram\Relation\OneToOne;
use JBZoo\MermaidPHP\ERDiagram\Relation\Relation;
use JBZoo\MermaidPHP\Render;

$diagram = (new ERDiagram(['title' => 'Order Example']));

$diagram
    ->addEntity($customerEntity = new Entity('C', 'Customer', props: [
        new EntityProperty('id', 'int', [EntityProperty::PRIMARY_KEY], 'ID of user'),
        new EntityProperty('cash', 'float'),
    ]))
    ->addEntity($orderEntity = new Entity('O', 'Order'))
    ->addEntity($lineItemEntity = new Entity('LI', 'Line-Item'))
    ->addEntity($deliveryAddressEntity = new Entity('DA', 'Delivery-Address'))
    ->addEntity($creditCardEntity = new Entity('CC', 'Credit-Card'))
    ->addRelation(new OneToMany($customerEntity, $orderEntity, 'places', Relation::ONE_OR_MORE))
    ->addRelation(new ManyToOne($lineItemEntity, $orderEntity, 'belongs', Relation::ZERO_OR_MORE))
    ->addRelation(new ManyToMany($customerEntity, $deliveryAddressEntity, 'uses', Relation::ONE_OR_MORE))
    ->addRelation(new OneToOne($customerEntity, $creditCardEntity, 'has', Relation::ONE_OR_MORE))
;
//header('Content-Type: text/plain');
//echo $diagram; // Get result as string (or $graph->__toString(), or (string)$graph)
$htmlCode = $diagram->renderHtml([
    'debug'       => true,
    'theme'       => Render::THEME_DARK,
    'title'       => 'Example',
    'show-zoom'   => false,
    'mermaid_url' => 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs',
]); // Get result as HTML code for debugging

echo $diagram->getLiveEditorUrl(); // Get link to live editor

Result

Open live editor

---
title: Order Example
---
erDiagram
    "Customer" ||--|{ "Order" : places
    "Line-Item" }o--|| "Order" : belongs
    "Customer" }o--|{ "Delivery-Address" : uses
    "Customer" ||--|| "Credit-Card" : has
    "Customer" {
        int id PK "ID of user"
        float cash
    }

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Timeline Diagrams

Create timeline visualizations for chronological data:

<?php

use JBZoo\MermaidPHP\Timeline\Timeline;
use JBZoo\MermaidPHP\Timeline\Marker;
use JBZoo\MermaidPHP\Timeline\Event;

$timeline = (new Timeline(['title' => 'History of Social Media Platform']))
    ->addSection(
        (new Timeline(['title' => 'Subsection 1']))
            ->addMarker(new Marker('2002', [
                new Event('Linkedin')
            ]))
    )
    ->addSection(
        (new Timeline(['title' => 'Subsection 2']))
            ->addMarker(new Marker('2004', [
                new Event('Facebook'),
                new Event('Google'),
            ]))
            ->addMarker(new Marker('2005', [
                new Event('Youtube'),
            ]))
            ->addMarker(new Marker('2006', [
                new Event('Twitter'),
            ]))
    )
;
//header('Content-Type: text/plain');
//echo $diagram; // Get result as string (or $timeline->__toString(), or (string)$timeline)
$htmlCode = $timeline->renderHtml([
    'debug'       => true,
    'theme'       => Render::THEME_DARK,
    'title'       => 'Example',
    'show-zoom'   => false,
    'mermaid_url' => 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs',
]); // Get result as HTML code for debugging

echo $diagram->getLiveEditorUrl(); // Get link to live editor

Result

Open live editor

timeline
    title History of Social Media Platform
    section "Subsection 1"
        2002 : Linkedin
    section "Subsection 2"
        2004 : Facebook : Google
        2005 : Youtube
        2006 : Twitter

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Class Diagrams

Generate UML class diagrams with relationships, namespaces, and cardinality:

<?php

use JBZoo\MermaidPHP\ClassDiagram\ClassDiagram;
use JBZoo\MermaidPHP\ClassDiagram\Concept\Concept;
use JBZoo\MermaidPHP\ClassDiagram\Concept\Attribute;
use JBZoo\MermaidPHP\ClassDiagram\Concept\Visibility;
use JBZoo\MermaidPHP\ClassDiagram\Concept\Method;
use JBZoo\MermaidPHP\ClassDiagram\ConceptNamespace\ConceptNamespace;
use JBZoo\MermaidPHP\ClassDiagram\Relationship\Relationship;
use JBZoo\MermaidPHP\ClassDiagram\Relationship\RelationType;
use JBZoo\MermaidPHP\ClassDiagram\Relationship\Cardinality;
use JBZoo\MermaidPHP\ClassDiagram\Relationship\Link;
use JBZoo\MermaidPHP\Render;

$diagram = (new ClassDiagram())
    ->setTitle('Animal example')
    ->setDirection(\JBZoo\MermaidPHP\Direction::TOP_TO_BOTTOM)
    ->addClass($animalClass = new Concept(
        identifier: 'Animal',
        attributes: [
            new Attribute('age', 'int', Visibility::PUBLIC),
            new Attribute('gender', 'String', Visibility::PUBLIC),
        ],
        annotation: 'abstract'
    ))
    ->addClass($duckClass = new Concept(
        identifier: 'Duck',
        attributes: [
            new Attribute('beakColor', 'String', Visibility::PUBLIC),
        ],
        methods: [
            new Method('swim')
        ],
    ))
    ->addRelationship(new Relationship(
        classA: $duckClass,
        classB: $animalClass,
        relationType: RelationType::REALIZATION
    ))
;
//header('Content-Type: text/plain');
//echo $diagram; // Get result as string (or $diagram->__toString(), or (string) $diagram)
$htmlCode = $diagram->renderHtml([
    'debug'       => true,
    'theme'       => Render::THEME_DARK,
    'title'       => 'Example',
    'show-zoom'   => false,
    'mermaid_url' => 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs',
]); // Get result as HTML code for debugging

echo $diagram->getLiveEditorUrl(); // Get link to live editor

Result

Open live editor

---
title: Animal example
---
classDiagram
direction TB
class Animal {
    <<abstract>>
    +int age
    +String gender
}
class Duck {
    +String beakColor
    swim()
}
Duck ..|> Animal

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Sequence Diagrams

<?php

use JBZoo\MermaidPHP\SequenceDiagram\ArrowType;
use JBZoo\MermaidPHP\SequenceDiagram\Message;
use JBZoo\MermaidPHP\SequenceDiagram\Note;
use JBZoo\MermaidPHP\SequenceDiagram\NotePosition;
use JBZoo\MermaidPHP\SequenceDiagram\Participant;
use JBZoo\MermaidPHP\SequenceDiagram\ParticipantType;
use JBZoo\MermaidPHP\SequenceDiagram\SequenceDiagram;
use JBZoo\MermaidPHP\SequenceDiagram\Block\Alt;
use JBZoo\MermaidPHP\SequenceDiagram\Block\Loop;

require_once './vendor/autoload.php';

$alice = new Participant('alice', 'Alice');
$john  = new Participant('john', 'John', ParticipantType::ACTOR);

$diagram = (new SequenceDiagram(['title' => 'Greeting', 'autonumber' => true]))
    ->addParticipant($alice)
    ->addParticipant($john)
    ->addMessage(new Message($alice, $john, 'Hello John', ArrowType::SOLID_ARROW, activateTarget: true))
    ->addMessage(new Message($john, $alice, 'Great!', ArrowType::DOTTED_ARROW, deactivateSource: true))
    ->addNote(new Note('a friendly hello', NotePosition::OVER, $alice, $john))
    ->addStatement(
        (new Alt('is well'))
            ->add(new Message($john, $alice, 'All good'))
            ->addElse('is sick')
            ->add(new Message($john, $alice, 'Not so good')),
    )
    ->addStatement(
        (new Loop('every minute'))
            ->add(new Message($alice, $john, 'ping')),
    );

echo $diagram; // Mermaid syntax
// echo $diagram->renderHtml(['theme' => 'dark']); // full HTML page

Produces:

---
title: Greeting
---
sequenceDiagram
    autonumber
    participant alice as Alice
    actor john as John
    alice->>+john: Hello John
    john-->>-alice: Great!
    Note over alice,john: a friendly hello
    alt is well
        john->>alice: All good
    else is sick
        john->>alice: Not so good
    end
    loop every minute
        alice->>john: ping
    end

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Output Formats

All diagram types support multiple output formats:

Mermaid Syntax

// Get raw Mermaid syntax
$mermaidCode = (string) $diagram;
echo $diagram; // or use __toString()

HTML with Embedded Viewer

// Generate complete HTML page with Mermaid viewer
$htmlCode = $diagram->renderHtml([
    'theme'       => Render::THEME_DARK,    // dark, forest, default, neutral
    'title'       => 'My Diagram',
    'show-zoom'   => true,
    'debug'       => false,
    'mermaid_url' => 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs'
]);

Self-Hosting & Offline (GDPR)

By default the generated page imports Mermaid from a public CDN. When the browser opens the page it sends the visitor's IP to that third party, which can be a GDPR concern and also prevents fully offline rendering. (The old builds also loaded jQuery from a CDN — that dependency has been removed entirely, the generated page is now jQuery-free.)

Use the mermaid descriptor to control how Mermaid is loaded. It binds the build flavor to its source, so there is a single, unambiguous option instead of guessing ESM vs UMD from a URL:

// 1) Default — ES module from a CDN (unchanged; equivalent to the legacy 'mermaid_url' option)
$diagram->renderHtml(['mermaid' => [
    'kind'   => 'esm-url',
    'source' => 'https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs',
]]);

// 2) Self-hosted from your OWN domain — no third-party request, browser-cacheable (best for production)
$diagram->renderHtml(['mermaid' => [
    'kind'   => 'umd-url',
    'source' => '/assets/js/mermaid.min.js',
]]);

// 3) Inlined into a single self-contained .html file — zero network requests (best for debug/review/CI artifacts)
$diagram->renderHtml(['mermaid' => [
    'kind'   => 'umd-inline',
    'source' => __DIR__ . '/assets/mermaid.min.js',
]]);

Notes:

• umd-url and umd-inline require the standalone UMD build (mermaid.min.js), which is a single self-contained file. The ESM build (mermaid.esm.min.mjs) is only a loader that fetches per-diagram chunks over the network at render time, so it cannot be self-hosted as one file or inlined.
• The library does not vendor Mermaid — download mermaid.min.js yourself (npm, or from the CDN) and point source at it. Nothing is fetched over the network by PHP during rendering.
• "Offline" caveats: inlining removes Mermaid's own requests, but fa: Font Awesome icons and custom web fonts are not embedded by Mermaid; provide them locally too if you need a provably request-free page.

Live Editor URL

// Get URL to Mermaid live editor for debugging
$url = $diagram->getLiveEditorUrl();

Development

Setup

# Install dependencies
make update

# Run tests
make test

# Run all tests and code quality checks
make test-all

# Run code style checks
make codestyle

Testing

• Unit Tests: PHPUnit tests in tests/ directory
• Code Coverage: Available via make report-all
• Static Analysis: Psalm integration for type safety

Useful Links

• Mermaid Documentation - Official Mermaid.js documentation
• Mermaid Live Editor - Online editor for testing diagrams
• Mermaid on GitHub - Source code and issues

License

MIT

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