HTML in, URL out. One API call turns HTML into a shareable link.

Create a Canvas

curl -X POST https://gui.new/api/canvas \
  -H "Content-Type: application/json" \
  -d '{"html": "
Hello
", "title": "My Canvas"}'

Response: {"id": "abc123", "url": "https://gui.new/abc123", "edit_token": "...", "expires_at": "..."}

Always share the url with the user after creating.

Update a Canvas

curl -X PUT https://gui.new/api/canvas/CANVAS_ID \
  -H "Authorization: Bearer EDIT_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"html": "
Updated
"}'

Extend Expiry

curl -X POST https://gui.new/api/canvas/CANVAS_ID/extend \
  -H "Authorization: Bearer EDIT_TOKEN"

Mermaid Diagrams

curl -X POST https://gui.new/api/flow \
  -H "Content-Type: application/json" \
  -d '{"mermaid": "graph TD\n  A[Start] --> B[End]"}'

Pro API Key (optional)

For extended expiry and higher limits, pass x-api-key header + "expires": "7d" body field (1h, 24h, 7d, 30d). No API key is needed for free tier usage.

Security Note

This skill sends HTML content to https://gui.new, a third-party hosted service. Do not send sensitive, private, or confidential data. Canvases are publicly accessible via their URL. Links expire (24h free, up to 30d Pro).

Built-in Components (auto-injected)

Use these tags directly — no script imports needed:

• code
• content

Real-Time Sync

All form inputs (text, range, select, checkbox) sync across viewers automatically. No setup needed.

Design Defaults

Dark background (#09090b), light text (#fafafa), system-ui font. Self-contained HTML with inline styles/scripts. Responsive.

Limits

Free: 2MB max, 24h expiry, 3 edits, 5 creates/hour. Pro: 10MB max, up to 30d expiry, unlimited edits, 100 creates/hour.

SDKs

• npm: npm install gui-new
• pip: pip install gui-new
• Full docs: https://gui.new/docs
• llms.txt: https://gui.new/docs/llms.txt