File size or complexity limits?

[EvilJordan]

I can't make this work at all with a complex SVG. Very basic stuff works, but as soon as multiple masks or gradients or many paths are introduced, it fails without outputting any information at all.

Are there known limitations?

[fuzhenn]

I think it may be due to upstream canvg's limitations of SVG feature supports, you can try there to see if there is any solution.