axidraw

Axidraw consumes SVG directly via an Inkscape extension and has an API to control at a lower level (presumably the Inkscape extension converts to the lower level API). Axidraw doesn’t use GCode from what I understand. There are a plethora of competitors/clones which do use GCode, and which require something like T2Laser to convert SVG to GCode. The AxiDraw firmware and extension are open source though: https://github.com/evil-mad/axidraw They also provide lots of single line fonts. A lot of users also utilize something like https://github.com/abey79/vpype to do post processing. This has a lot of useful resources: https://github.com/beardicus/awesome-plotters#software

I bought an Axidraw recently and its been great, its a fairly robust device. Plotting quality has been great, although it takes some learning on how to use it. They also take care to use non-proprietary firmware, and publishes it as open source: https://github.com/evil-mad/axidraw