Built for engineers, DevOps & data teams

Diagrams that speak your stack.

Turn Mermaid and D2 into editable shapes, import Compose and Kubernetes as architecture, visualize a query plan, and drive it all from an API.

Open LetDraw, free Explore features
MermaidD2Docker ComposeKubernetesEXPLAINREST + MCP
architecture.letdraw
namespace: prod API ×3 pods Cache redis Postgres
// From code

Mermaid and D2 in, editable shapes out

Paste the diagram code you already have and get real, movable shapes back, in the sketchy style. Tweak it by hand, then export it back to Mermaid or D2 when you need code again.

  • Round-trip: code to canvas and back to code
  • Native arrowheads and ER crow's-foot, no hand-drawn hacks
  • Smart connectors route around your shapes automatically
flow.mmd → canvas
graph TD
  A[Client] --> B(API Gateway)
  B --> C{Auth?}
  C -->|yes| D[Service]
  C -->|no| B
  D --> E[(Postgres)]
# paste it → get editable shapes
# edit → export back to Mermaid / D2
// Generate from code

One dialog, almost any source

Paste your infra or a spec and LetDraw figures out what it is, then lays out the diagram, clusters related pieces and stamps the right product icons. No manual boxing.

  • Auto-detects the format, no picking from a menu
  • Clustered layout that mirrors your namespaces
  • Product icons for Kubernetes, Terraform and cloud services
Docker ComposeKubernetesTerraformHelmGraphviz DOTSQL DDLOpenAPIgit logEXPLAINMermaidD2
docker-compose.yml → diagram
services:
  web:
    image: nginx
    depends_on: [api]
  api:
    image: app:latest
    depends_on: [db, redis]
  db:
    image: postgres:16
  redis:
    image: redis:7
# → clustered architecture with icons
// For your database

See your query plan, not a wall of JSON

Paste a Postgres or MySQL EXPLAIN output and LetDraw renders a heat-mapped plan tree. The expensive nodes light up, so the slow part of the query is obvious at a glance.

  • Postgres and MySQL EXPLAIN (JSON) auto-detected
  • Heat-mapped by cost, hottest nodes first
  • Runs client-side, your query never leaves the browser
EXPLAIN (FORMAT JSON)
Hash Join cost 8420 · 92% Seq Scan orders cost 3110 · 34% Index Scan users cost 210 · 4% Bitmap Index
// Automate it

A REST API and an MCP server

Generate a personal token, then create, edit and export diagrams from a CI script, a cron job or an AI agent. Scoped permissions keep each token to exactly what it needs.

  • Scopes: read, write, export (Mermaid / D2 / SVG), AI generate
  • MCP server so an AI assistant can draw for you
  • Great for docs pipelines and generated architecture
generate from CI
# create a diagram from a prompt
curl https://letdraw.com/api/v1/generate \
  -H "Authorization: Bearer $LD_TOKEN" \
  -d '{ "prompt": "3-tier web app", "format": "mermaid" }'

# or wire the MCP server into your AI tool
"letdraw": { "command": "letdraw-mcp" }
// Model it

ER and UML that stay correct

Design schemas and systems with real notation. Crow's-foot cardinality on ER relations, hollow arrowheads for UML, and foreign-key routing that goes around tables instead of through them.

  • ER tables with typed columns and keys
  • UML class diagrams with proper arrowheads
  • Smart FK routing keeps lines readable
schema.er
users 🔑 id email created_at orders 🔑 id user_id ↗ total
// Think in branches

Mind maps that lay themselves out

Start from one idea and press Tab to branch. LetDraw arranges the layout for you, so you capture a brainstorm as fast as it comes, then turn it into a real diagram.

  • Keyboard-first: Tab adds a child, no dragging boxes
  • Auto-layout keeps every branch tidy as it grows
  • Collapse and expand branches to focus
  • Flip between horizontal and vertical in one click
brainstorm.mindmap
Main idea Research Audience Design Launch Users Market
And a lot more on the canvas

Everything you reach for, in one place

The building blocks that turn a rough sketch into something you can hand off.

Prompt to diagram

Describe it in words and get an editable draft. 3 free on any plan, or bring your own key.

Explain diagram

Turn a drawing into clear prose or Markdown docs, so a diagram ships with its own write-up.

Smart connectors

Orthogonal routing that avoids obstacles automatically, so arrows never cut through boxes.

Multi-point arrows

Click to add bends to arrows and lines, then flip, rotate and edit every point.

Tables & code blocks

Editable tables and syntax-styled code blocks as first-class shapes, not flattened images.

Export & record

PNG, SVG, PDF, copy to clipboard, or record your drawing process as a WebM video.

Math / LaTeX

Type a formula, preview it live (rendered with KaTeX) and drop it on the canvas. A symbol keyboard is one tap away.

Quick charts

Bar, pie and line charts from a tiny data table, as editable shapes you can restyle and export.

Embed a live board

Paste a snippet into any README, wiki or docs page to embed a live, read-only view of a diagram.

Sketchy aesthetic

Hand-drawn look that keeps early diagrams friendly, with a clean mode when you want it crisp.

Offline & private

Works in the browser with no install, drawings stay local, and there is no third-party tracking.

Real-time collaboration

Draw together with live cursors, comments and workspace roles. See Collaborate →

Diagram your system in a browser tab.

No install, no setup. Paste some code, import your infra, or just start drawing.