The gist

OpenPencil is an open-source vector design application that creates and edits interface layouts through chat prompts. Multiple artificial intelligence assistants work together across different sections of a shared canvas in real time. It is aimed at product designers and design-focused developers rather than complete beginners.

What it does

Turns plain-text prompts into vector user interface layouts on an infinite canvas
Coordinates multiple AI assistants to build different sections of a page in parallel
Updates designs interactively when you select canvas elements and request changes
Applies pre-built style guides to match visual aesthetics such as retro or modern themes
Connects to major AI model providers using your own API account credentials

How it works

You describe the interface or screen layout you want in plain text on a live canvas. A coordinator splits the page into smaller visual sections and delegates them to multiple AI assistants at the same time. The assistants generate vector shapes and components through external AI model services. You can then click any element to adjust or restyle it with further prompts.

Best for

UI designers looking to rapidly explore layout concepts and visual variations with AI
Product teams wanting a free, open-source alternative to proprietary vector design apps
Designers and technical creators comfortable setting up their own AI model API keys

Watch out for

Requires bringing your own API keys for AI models (such as Anthropic or OpenAI), which cost money per request
Early-stage open-source project that may have interface bugs or frequent changes
Not built for non-technical beginners; requires initial configuration of model endpoints

What you need: Install it on your own computer. Cost: free, open source.