Free AI UML Diagram Generator — Create Class, ER, Sequence, Use Case & Activity Diagrams Online | AutoUML

AI-powered · No sign-up · Export ready

Describe it.
We draw it.

Write your system in plain English — AutoUML generates Class, ER, Sequence, Use Case, and Activity diagrams in under 2 seconds. Then edit, export, and share.

Open AutoUMLFree to use · No account needed
2s
Average generation time
5
Diagram types supported
2
Export formats (PNG & PDF)
0
Sign-ups required to start
Diagram Types

Five UML diagram types. One free AI tool.

Class Diagram
OOP structures — classes, inheritance, interfaces, access modifiers, and methods.
UML 2.5
ER Diagram
Database tables, primary & foreign keys, cardinalities, and relationships.
ERD / DBML
Sequence Diagram
API call flows, auth lifecycles, and message passing between actors and services.
Interaction
Use Case Diagram
Define actors, system boundaries, and feature interactions for requirements docs.
Behavioral
Activity Diagram
Business process flows, decision branches, forks, and system workflow states.
Workflow
Process

How to generate UML diagrams
with AI in 3 steps.

— 01
Describe your system
Type out your database schema, class structure, or process flow in plain English. No special syntax, no learning curve.
— 02
AI generates it
The model parses your description and renders a properly structured, connected diagram — nodes, edges, cardinalities, all handled.
— 03
Edit and export
Drag, resize, rename, reconnect. When it looks right, export as PNG or PDF and drop it anywhere — docs, slides, Notion, Confluence.
PlantUML Support

Paste PlantUML code.
Render diagrams offline.

Have existing PlantUML scripts? Just paste them into AutoUML. Our robust offline parser instantly renders your code into a professional diagram, entirely in your browser—without spending your AI quota.

Zero Quota Cost
Conversion runs locally, saving your AI limits
Auto-Detection
Automatically identifies and styles diagram types
Import PlantUML
PlantUML Code
Auto-detected: Class
@startuml
class User {
  + id: uuid
}
class Order
User "1" -- "*" Order
@enduml
Export

Export UML diagrams
as PNG or PDF instantly.

No watermarks, no compression. Export your finished diagram as a sharp PNG for slides and docs, or a print-ready PDF for formal deliverables.

PNG Image
Perfect for presentations, wikis, and quick sharing
.png
PDF Document
High-resolution, print-ready for formal documentation
.pdf
diagram.png — export preview
Userclass
+ id: uuid
+ email: string
+ role: enum
owns
Workspaceclass
+ id: uuid
+ name: string
+ plan: string
PNG
PDF
Bring Your Own Key

Unlimited UML generation
with your own API key.

AutoUML gives you free generations out of the box. When you run out, paste your own API key from Gemini, OpenAI, or Grok — and keep going. Your key, your usage, your cost.

GeminiGoogle AI
OpenAIGPT-4o
GrokxAI

Your key is stored only in your browser's local storage — it never touches our servers.

Settings · API Keys
AI ProviderOptional — free tier available
AIza••••••••••••••••••••••••••••

Get your key at aistudio.google.com

Key active · Gemini 2.0 Flash
verified
— 01
Hit your free limit
AutoUML gives you a set of free generations — no account needed. Use them freely.
— 02
Paste your API key
Open Settings, pick your provider — Gemini, OpenAI, or Grok — and paste your key.
— 03
Keep generating
AutoUML uses your key directly. You pay your provider's rate, we add zero markup.
Premium · Coming Soon

More power, on the way.

We're building premium features for teams and heavy users. Early access is free — join the waitlist and be first in.

Unlimited generations
No free-tier ceiling
soon
Diagram history
All your past diagrams saved
soon
Share links
View-only public links
soon
Priority AI model
Faster, smarter generation
soon
Join the waitlist
Early access is free

No commitment · Cancel anytime

Who It's For

AI UML tool for students,
developers & teams.

Most Popular
University Students
Ace software engineering assignments with correct UML — instantly, no Lucidchart trial needed.
  • Class diagrams for Java and Python projects
  • ERDs for database design coursework
  • Sequence diagrams for OS and networking
Engineering Teams
Go from system spec to shareable diagram in seconds. Export directly into your wiki or docs.
  • Architecture maps for microservices
  • API flow documentation for new engineers
  • Onboarding diagrams that stay up to date
Solo Developers
Use it as a full diagramming canvas — AI optional. Clean controls, professional exports, no lock-in.
  • Plan side projects visually before coding
  • Share readable specs with collaborators
  • Skip subscription tools entirely
— Start now, free

Your first diagram, under 30 seconds.

No sign-up. No credit card. Just open and describe.

Open AutoUML
Works for students, teams, and everyone in between
Contact Us

Let's build together.

Have a question about API keys, enterprise needs, or general feedback? Reach out and we'll get back to you within 24 hours.

Have a feature request or found a bug?Submit in App
FAQ

Frequently asked questions
about AutoUML.

What is AutoUML?

AutoUML is a free, AI-powered UML diagram generator. Describe your system, database, or process in plain English and AutoUML generates a professional UML diagram in under 2 seconds — no sign-up required.

What types of UML diagrams can AutoUML generate?

AutoUML generates 5 diagram types: Class Diagrams (OOP structures), ER Diagrams (database schemas), Sequence Diagrams (API and auth flows), Use Case Diagrams (actor-system boundaries), and Activity Diagrams (business process workflows).

Is AutoUML free to use?

Yes. AutoUML is completely free with no account or credit card required. You get a set of free AI generations out of the box. Need more? Plug in your own API key from Gemini, OpenAI, or Grok at zero markup.

Do I need to sign up or create an account?

No. AutoUML requires no account, no sign-up, and no credit card to start. Just open the app and describe your system.

What export formats does AutoUML support?

AutoUML exports as PNG (sharp, high-resolution for presentations, Notion, wikis) and PDF (print-ready for formal documentation). No watermarks added.

Does AutoUML support PlantUML code?

Yes. Paste any existing PlantUML script into AutoUML. The offline parser auto-detects the diagram type and renders it instantly — without using your AI generation quota.

What is the BYOK (Bring Your Own Key) feature?

BYOK lets you paste your own Gemini, OpenAI, or Grok API key for unlimited generations. Your key is stored only in your browser's local storage and never touches our servers.

How is AutoUML different from Lucidchart or draw.io?

Unlike Lucidchart or draw.io where you manually drag and drop, AutoUML generates complete, correctly structured UML diagrams from plain English descriptions using AI. It's purpose-built for speed — from idea to finished diagram in seconds.