Remove unknowns & defaults (removeUnknownsAndDefaults)
Drops attributes and elements that match SVG defaults or are unknown to the spec.
What Remove unknowns & defaults does in SVGO
SVGO applies removeUnknownsAndDefaults as part of its plugin pipeline. In SVGOMG the toggle is labeled Remove unknowns & defaults (enabled by default). Optimization runs entirely in your browser — files are not uploaded to a server.
Use the SVGOMG optimizer with Show original to compare before and after. If output looks wrong, disable this plugin first, then re-enable related transforms one at a time.
When to enable
Safe default for shrinking verbose editor output.
When to disable
When targeting non-standard attributes your runtime depends on.
Watch out for
May remove vendor-specific attributes you still need.
Try it in SVGOMG
- Open svgomg.net and load your SVG (file, paste, or demo).
- Find Remove unknowns & defaults in the Features panel (
removeUnknownsAndDefaults). - Toggle the plugin and compare the preview; download when satisfied.
SVGO Plugin Guide
Browse the SVGO Plugin Guide or read the full SVG optimization walkthrough on the homepage.