ASCII Architecture & Diagram Sketcher

Diagrams

Design system architectures, sequence flows, and state machines in ASCII and Unicode. Copy to Markdown or export to SVG.

Private by architecture: All processing is 100% client-side memory. Your data never leaves this browser tab.

Architecture Presets Select template to start

Insert Snippet:

Diagram Source (Monospace Editor) 0 lines | 0 chars

Rendered Visual Preview

Lines 0

Max Width 0 cols

Encoding UTF-8

Box Drawing Cheatsheet

Unicode Single:
┌ ─ ┐ │ └ ─ ┘

Unicode Double:
╔ ═ ╗ ║ ╚ ═ ╝

Directional Arrows:
◄ ─ ► ▲ │ ▼

ASCII Compatible:
+ - + | + - +

About This Tool

Diagramming system architecture, database relations, and API sequence flows directly in code comments or GitHub pull request descriptions requires clean text diagrams that render everywhere. This sketcher lets you draft, align, and customize box-and-arrow diagrams using standard ASCII or modern Unicode box drawing characters.

Export your finished sketches as plain text, Markdown-compatible fenced code blocks, or crisp vector SVG cards suitable for technical documentation and slide decks. Everything runs client-side inside your browser with zero latency and zero data transfer.

Key Features

Rich architecture presets: Instantly load microservices, OAuth sequence flows, git branch trees, and bento-box layouts.
Unicode & ASCII box drawing: Seamlessly switch between classic ASCII (+ and -) and Unicode single, double, or rounded corners.
One-click Markdown & SVG export: Copy formatted markdown code blocks or download scalable vector graphics with dark-mode styling.
Live preview & character metrics: Inspect line counts, character bounds, and visual density in real time as you sketch.
100% private and offline: All grid rendering and SVG conversions execute locally in your browser memory.

Frequently Asked Questions

Why use ASCII diagrams instead of PNG images in documentation?

ASCII and Unicode diagrams live directly inside READMEs, pull requests, and source code comments. They are version-controlled via git, easily searchable with grep, diff-friendly, and require no image hosting or external URLs.

Will Unicode box characters render correctly in standard terminal windows?

Yes. Modern terminal emulators and code editors (VS Code, Neovim, iTerm2, Alacritty) support Unicode UTF-8 Box Drawing characters (U+2500 through U+257F). For legacy environments, you can switch to pure ASCII mode (+, -, |).

How do I embed the diagram into a GitHub README or Pull Request?

Click "Copy Markdown". This wraps your diagram inside a triple-backtick text code block so GitHub and GitLab render it with a monospace font and preserved spacing.

Is my diagram data sent to any server?

No. The diagram generator and SVG exporter run entirely on your local machine in client-side JavaScript.