# SVG Optimizer

> Shrink and sanitise SVG files: strip editor junk and scripts, round numbers, minify paths. Optimises an SVG file in your choice of steps and shows how many bytes each one saved: removes comments, metadata and Inkscape/Illustrator editor data, hidden and empty elements, rounds numbers, rewrites path data in its shortest form and collapses whitespace. It also removes scripts, event handlers and external references, so the result is safe to embed.

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://svgoptimizer.usefulweb.site/ (interactive tool at https://svgoptimizer.usefulweb.site/tool)
- JSON API: POST https://svgoptimizer.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://svgoptimizer.usefulweb.site/api/v1/tool)
- OpenAPI: https://svgoptimizer.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://svgoptimizer.usefulweb.site/mcp - tool `svg_optimizer`

## Inputs
- svgFile (file): SVG file - An .svg or .svgz file, max 5 MB. Alternatively paste the SVG code below.
- svgText (textarea): Or paste SVG code
- precision (integer): Decimal places - Coordinates and lengths are rounded to this many decimals. 1–3 is usually invisible; transforms keep two more.
- minifyPaths (boolean): Minify path data (shortest relative/absolute commands)
- removeHidden (boolean): Remove hidden elements and unused definitions
- removeDimensions (boolean): Remove width/height (keep viewBox so the SVG scales responsively)

## Method
- The SVG is parsed by a strict built-in XML parser (no external entities; internal DOCTYPE entities are expanded once with a size cap, which blocks "billion laughs" files). The document is re-serialised after every step, and the byte count before/after each step is reported.
- Security (always on): removes <script>, <foreignObject>, <iframe>/<embed>/<object>, all on* event handlers, javascript: links, xml:base, CSS @import and url() references to other files, external href on <use>/<image>/<feImage> (raster data: URIs are kept), and animations that change href or event attributes. Links in <a> may point to http(s) or mailto only.
- Clean-up: comments, XML declaration, DOCTYPE and processing instructions; <metadata>, RDF and editor namespaces (Inkscape, Sodipodi, Illustrator, Sketch, Serif, Figma); elements with display:none that nothing references; unreferenced children of <defs>; empty groups, and groups without attributes are unwrapped; unused namespace declarations, version and baseProfile.
- Numbers in geometry attributes are rounded to the chosen decimal places (transforms to two more) with leading zeros dropped. Path data is re-written per segment in whichever of absolute or relative form is shorter, lines become H/V where possible, repeated command letters are omitted, and relative values are computed from the rounded current point so errors do not accumulate.
- Whitespace between elements is removed except inside text elements and xml:space="preserve". Removing width/height keeps (or creates) the viewBox so the graphic still scales.
- The optimised SVG is offered as a download (served as an attachment, never rendered on this site).

## Limits
- Check the optimised file visually: very low precision can shift shapes, and removing width/height changes how some programs size the image.