Is the diagram source uploaded to a server?

No. Rendering happens in your browser, so your diagram source stays local and private.

Which output formats are supported?

You can export diagrams as SVG, PNG, JPEG, PDF, TXT, or Base64 depending on the diagram type.

Can I copy the generated diagram?

Yes. You can copy image outputs (SVG/PNG/JPEG) to the clipboard and copy text outputs directly.

Does it work offline?

Once the page loads, most operations run locally in the browser. Some exports may require fetching the rendered output.

Diagram Viewer – Render, Preview & Export Diagrams Online

Render and preview diagrams in multiple formats (SVG, PNG, PDF, TXT). Copy, download, and share diagram outputs from popular diagram syntaxes like Mermaid and PlantUML.

Render and export technical diagrams from plain-text diagram source. Pick a diagram type, paste your diagram code, and export as SVG/PNG/PDF (availability depends on the syntax).

This Diagram Viewer is powered by Kroki. Your diagram source is sent to kroki.io to generate previews and downloads, so avoid putting secrets in diagrams.

How to use the Diagram Viewer

Choose a diagram type (e.g. Mermaid, PlantUML, GraphViz).
Paste your diagram source into the editor.
Select an output format (SVG/PNG/PDF/etc).
Use Copy, Download, or Open in new tab.

Tip: start with SVG for crisp, scalable output.

Supported diagram types

This tool supports many Kroki-backed syntaxes, including:

Mermaid
PlantUML (and C4 with PlantUML)
GraphViz (DOT)
BPMN
D2
DBML
Excalidraw
Structurizr
TikZ
Vega / Vega-Lite

The available export formats vary by diagram type. Most types support SVG, and many support PNG and PDF.

Examples

Mermaid (flowchart)

flowchart LR
	A[Client] --> B[API]
	B --> C[(DB)]

PlantUML (sequence)

@startuml
Alice -> Bob: Hello
Bob --> Alice: Hi
@enduml

GraphViz (DOT)

digraph G {
	rankdir=LR;
	A -> B;
	B -> C;
}

Privacy & offline notes

This tool requires an internet connection to render diagrams (via Kroki).
Diagram source is sent to Kroki to generate previews/exports. Don’t include credentials, tokens, or private keys.

JSON Formatter (format diagram configs like JSON)
Base64 Encoder & Decoder (encode SVG/PNG outputs for embedding)
All tools