cad-viewer

cad-viewer opens AutoCAD drawings (DXF and DWG files) in a web browser and lets you edit them, with no server. The file is parsed on the user's own device and never uploaded. It ships as npm packages and a one-line iframe embed, so you can drop a CAD viewer into your own app. MIT.

DXF works out of the box with the project's own MIT parser. DWG, the format most people actually have, is where licensing kicks in: the open source route uses LibreDWG, which is GPL-3.0, adds roughly 13MB to the download, and still covers drawing entities only partially. There's also an AI assistant plugin that draws lines, circles and layers from a chat panel, using your own OpenAI or Anthropic key.

Internal tools and open source projects: use it freely, DWG included. Closed-source products that need DWG either comply with the GPL or buy the maintainer's commercial parser: $3,000 for a perpetual license, then $1,500 a year if you want upgrades.

The catch: very large DWG files can run the browser out of memory, and the commercial parser's trial licenses go only to companies, not individuals.