How to svg base64 encoding: practical use cases and when to avoid it
- Step 1Identify your embedding context — JSON payload or React Native Image? Use Base64. CSS background-image? Use URL encoding (smaller). HTML img src? Use an external URL (best for caching).
- Step 2Compare the encoded sizes — Run your SVG through both the Base64 encoder and the CSS Data URI generator. Compare output lengths — URL encoding is typically 5–15% shorter for SVG content.
- Step 3Choose based on cacheability — Base64 and URL-encoded data URIs cannot be independently cached. If the SVG is used in multiple places, an external URL with proper cache headers is almost always better.
Frequently asked questions
Why is URL encoding better than Base64 for CSS backgrounds?+
SVG consists of mostly ASCII characters that URL-encode to themselves or short escape sequences. Base64 expands every 3 bytes to 4 characters uniformly. For SVG, URL encoding produces shorter output.
Does React Native's Image component support URL-encoded SVGs?+
React Native's Image source requires Base64 data URIs for embedded images: source={{ uri: 'data:image/svg+xml;base64,...' }}. URL-encoded SVGs are not reliably supported across React Native versions.
Can I use Base64 SVG in a CSS custom property?+
Yes: --icon: url('data:image/svg+xml;base64,[encoded]'). Reference it as background-image: var(--icon). This works in all modern browsers.
Should I store Base64 SVGs in a database?+
Only if the SVG is very small and used as an attribute value. Storing large Base64 SVGs in database columns is inefficient — store the SVG source or a file URL instead.
Privacy first
Every JAD SVG tool runs entirely in your browser using the DOM API and Canvas. Your SVG files never leave your device — verified by zero outbound network requests during processing.