What is ASCII Diagram Editor?

ASCII Diagram Editor is an interactive tool for creating diagrams, flowcharts, and illustrations using plain text characters. It supports both traditional ASCII characters (+, -, |) and Unicode box-drawing characters (┌, ─, │, →) for cleaner visuals.

Text-based diagrams are widely used in documentation, code comments, README files, and technical specifications because they work everywhere — no special software or image viewers needed.

Why Use Text Diagrams?

Universal Compatibility

Displays correctly in any text editor, terminal, or code viewer without special software

Version Control Friendly

Diffs and merges work naturally with plain text, perfect for Git workflows

Lightweight

No image files to manage, host, or worry about broken links

Copy-Paste Ready

Share diagrams instantly in emails, chat, or documentation

How to Use

Drawing Tools

Select a drawing tool from the toolbar or use keyboard shortcuts for quick access:

Box (B)

Click and drag to draw rectangles with proper corners and edges

Line (L)

Draw horizontal or vertical lines by dragging

Arrow (A)

Draw lines with directional arrowheads at the endpoint

Text (T)

Click anywhere on the canvas and start typing labels

Eraser (E)

Click or drag to remove characters from the canvas

Select (V)

Select a region to move, copy, or delete it

Character Sets

Toggle between two character styles using the charset buttons:

ASCII

Basic Characters

Uses classic characters: +--+, |, >, <

Works everywhere
Maximum compatibility
Terminal-safe

Unicode

Box-Drawing Characters

Uses dedicated characters: ┌──┐, │, →, ←

Cleaner appearance
Professional look
Requires Unicode support

Working with Selections

Use the Select tool to interact with existing content:

Activate Select Tool

Press V or click the Select button in the toolbar

Create Selection

Click and drag to create a selection area around your content

Move or Edit

Drag the selected area to move it, press Delete to clear, or Ctrl+C to copy

Exporting Your Diagram

When your diagram is ready, choose your export method:

Copy — copies the entire canvas content to your clipboard for immediate pasting
Export — downloads your diagram as a .txt file for saving or sharing

Pro Tip: Both export options automatically trim trailing whitespace for clean, professional output.

Features

Drawing Tools

Six specialized tools cover all common diagramming needs. Draw boxes for containers, lines for connections, arrows for direction, and add text labels — all with live preview as you drag.

Dual Character Sets

Switch between ASCII and Unicode box-drawing characters at any time. ASCII mode uses classic characters compatible with any system, while Unicode mode produces cleaner, more polished diagrams.

Select and Move

The Select tool lets you pick up parts of your diagram and reposition them. Select a region, then drag it to a new location. You can also delete or copy selected content.

Full Undo/Redo History

Every change is tracked with up to 50 history states. Use Ctrl+Z and Ctrl+Y to step through your editing history.

Adjustable Canvas

Resize the canvas width from 20 to 200 columns to fit your diagram. The grid background automatically aligns with character cells for precise placement.

Keyboard Shortcuts

Quick tool switching with single-key shortcuts: V (Select), B (Box), L (Line), A (Arrow), T (Text), E (Eraser). Combined with Ctrl shortcuts for undo, redo, and copy.

Export Options

Copy your diagram to the clipboard for immediate pasting, or download it as a plain text file. Trailing whitespace is automatically trimmed for clean output.

Your Data Stays Private

All drawing happens in your browser. No uploads — your diagrams never leave your device. No tracking — we don't collect usage data.

Privacy First: This tool runs entirely in your browser. Your diagrams are never uploaded to any server, ensuring complete privacy and security.

Frequently Asked Questions

What is the difference between ASCII and Unicode mode?

ASCII mode uses basic characters like +, -, | that work in every text environment. Unicode mode uses dedicated box-drawing characters like ┌, ─, │ that produce cleaner-looking diagrams but require Unicode support in the viewer.

Use ASCII when: Maximum compatibility is needed (terminals, legacy systems, plain text emails)

Use Unicode when: You want professional-looking diagrams in modern documentation

Can I switch character sets after drawing?

Yes, but switching only affects new drawings. Existing characters on the canvas remain unchanged. This allows you to mix both styles in a single diagram if needed.

Tip: You can create hybrid diagrams by drawing the main structure in Unicode for clean lines, then adding ASCII annotations for maximum compatibility.

What is the maximum canvas size?

The canvas supports:

Width: 20 to 200 columns
Height: 10 to 100 rows
Default size: 100 columns × 30 rows

The default size works well for most diagrams and fits comfortably in documentation without horizontal scrolling.

How do I move part of a diagram?

Switch to the Select tool by pressing V
Drag to create a selection around the area you want to move
Drag the selected content to its new position
Click outside the selection to deselect

You can also press Delete to remove the selected content or Ctrl+C to copy it to your clipboard.

Can I undo my changes?

Yes, the editor supports full undo and redo functionality:

Press Ctrl+Z to undo your last action
Press Ctrl+Y to redo an undone action
Up to 50 history states are preserved

Every drawing action, text input, and deletion is tracked, giving you complete control over your editing history.

How do I export my diagram?

You have two export options:

Copy

Clipboard Export

Click the Copy button
Diagram is copied to clipboard
Paste directly into documents

Export

File Download

Click the Export button
Downloads as .txt file
Save for later or share

Both options automatically trim trailing whitespace for clean, professional output.

Does this tool work on mobile devices?

Yes, the editor supports touch input for drawing. However, for the best experience with precise character placement, a desktop browser with a mouse or trackpad is recommended.

Mobile limitations: Touch-based selection and precise character placement can be challenging on small screens. For complex diagrams, we recommend using a desktop device.