Free · No sign-up · Runs in your browser

Render PlantUML beautifully.
Convert to Mermaid when it maps.

Plantraft renders PlantUML by default, auto-detects diagram types, and creates Mermaid-compatible output for supported syntax. Compatibility badges show Two-way, Partial, PlantUML-only, or Mermaid-only status.

No installation. No account. Free to use.

Plantraft
Auto-detected · Sequence
SVG
PNG
PlantUML
Mermaid
1@startuml
2title User Login Flow
3
4actor User
5participant "Web App" as App
6participant "Auth Service" as Auth
7
8User -> App : Enter credentials
9App -> Auth : POST /login
10Auth --> App : JWT token
11
12note right of Auth : Token expires
13@enduml
PlantUML
Mermaid
Theme: Ocean
User Web App Auth Enter credentials POST /login JWT token Token expires User Web App Auth

Three steps to a beautiful diagram

No setup, no install. Just paste your diagram code and Plantraft does the rest.

Step 01
✍️
Write your source

Type or paste PlantUML or Mermaid code into the left editor pane. Familiar syntax highlighting and line numbers keep you oriented.

Step 02
Auto-detect & convert

Plantraft reads your code, detects the diagram type and compatibility level, then updates Mermaid-compatible output when the syntax is supported.

Step 03
🎨
Render, theme & export

Pick one of five themes to style your diagram. Zoom and pan for detail. Export as crisp SVG or 2× PNG — ready for docs, slides, or anywhere else.


Everything you need to diagram faster

Built for developers, architects, and anyone who thinks in text.

🔄
Compatibility-aware conversion

Generate Mermaid-compatible output when a diagram type maps cleanly. Partial and dedicated syntax are labeled before you rely on the result.

🧠
Auto diagram detection

No dropdowns to set. Plantraft reads your code and picks the right compatibility path across Sequence, Class, State, Activity/Flowchart, ER, Gantt, Mindmap, Pie, and PlantUML-only diagrams.

🏷️
Compatibility badges

Plantraft labels each diagram Two-way, Partial, PlantUML-only, or Mermaid-only, so compatibility is visible before export.

🌐
Dual renderers

Compare the Mermaid render (in your browser) and the PlantUML render side by side. Switch between them with a single click.

🔍
Pan & zoom

Scroll to zoom, drag to pan, click ⤢ to fit. Works on every diagram type. Zoom up to 600% with pixel-perfect SVG quality.

📦
SVG & PNG export

Download your diagram as a clean SVG vector or a 2× high-resolution PNG with theme-matched background. Ready for any use.


Five carefully crafted color palettes

Every theme applies harmonious colors to nodes, text, lifelines, notes, and actor figures — not just backgrounds.

Ocean
Cerulean blue, clean & focused
Forest
Emerald green, calm & natural
Blossom
Dusty rose, soft & warm
Midnight
Deep navy, sharp & dramatic
Sunshine
Amber honey, warm & energetic

What is Plantraft?

Plantraft is a free, browser-based, PlantUML-first diagram editor for software engineers, system architects, and technical writers who prefer diagrams as code.

It renders PlantUML as the primary source and provides Mermaid-compatible conversion where the diagram syntax maps cleanly. Supported types are marked Two-way, partial conversions are labeled with loss warnings, and PlantUML-only or Mermaid-only diagrams stay clearly identified.

All computation happens in your browser. No data is sent to any server except when using the optional PlantUML preview tab, which sends your diagram code to the public plantuml.com rendering server.


Frequently asked questions

What's the difference between PlantUML and Mermaid?
Both are text-based languages for drawing diagrams from code. PlantUML is older and covers a very wide range of UML and non-UML diagrams, while Mermaid is lighter and renders natively in many tools like GitHub, GitLab, and Notion. Plantraft is PlantUML-first: it renders PlantUML by default and creates Mermaid-compatible output when the diagram type maps cleanly.
Can I convert Mermaid to PlantUML and PlantUML to Mermaid?
Supported diagrams can convert in both directions when the syntax maps cleanly. Plantraft labels each result as Two-way, Partial, PlantUML-only, or Mermaid-only, so you know what will map, what may lose detail, and what stays in its native syntax.
Which diagram types are supported?
Two-way: Sequence, Class, State, ER, Gantt, and Mindmap. Partial: Activity/Flowchart. Mermaid-only: Pie direct input. PlantUML-only: Use Case, Component, Deployment, Object, Timing, WBS, Salt, JSON, YAML, EBNF, Network, Packet, Regex, Math, Chen, File Tree, Ditaa, C4, ArchiMate, and Chart.
Is Plantraft free? Do I need an account?
Plantraft is completely free and needs no sign-up or installation. Just open the editor in your browser and start typing.
Is my diagram data private?
Conversion and the Mermaid preview run entirely in your browser — your code is not sent anywhere. The only exception is the optional PlantUML preview tab, which sends your code to the public plantuml.com rendering server. Your work is also auto-saved locally in your browser so it survives a refresh.

Still have a question, or ran into a problem? Email us at contact@plantraft.com and we'll be happy to help.


Start diagramming right now

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