Runs in your browser · nothing to install · bring your own API key
Build LEGO® models online, in 3D.
Describe a model and Claude builds it from real parts, in 3D, checking that it holds together, on your own Anthropic API key. Plus a catalog of every part with 3D previews, and more than 1,400 official sets you can open in 3D, take apart, and remix.
No sign-up: Claude builds on your own Anthropic API key, kept in your browser. It plans the build, places real parts by their real connections, and checks that the result stands up.
AI builder · bring your own key
Create
Describe a model and Claude builds it from real parts while you watch, then checks that it holds together. The same app as on the Mac, in your browser, on your own Anthropic API key.
5,459 parts with 3D geometry
Directory
Parts
Browse and search the full parts catalog with live 3D previews, categories, and color availability.
63,560 parts · 274 colors
Directory
Builds
Official sets rebuilt brick for brick, the builds you saved yourself, and thousands of generated structures — every one of them opens in the editor.
1,464 sets in 3D · 47,389 structures
New · desktop app for Mac · beta
Build with your own AI agent
Danish Bricks Builder for Mac opens a folder of models, shows them in 3D, checks that they hold together, and lets Claude Code or Codex do the building while you watch. Your files stay on your Mac.