Supported browsers
SecretPNG runs in current versions of the major browsers. A couple of capabilities differ between them — here is exactly what changes.
| Browser | Versions | Large-file streaming | Notes |
|---|---|---|---|
| Google Chrome | Current stable | Yes — streams to disk | Full support, including File System Access API for large files and PWA install for offline use. |
| Microsoft Edge | Current stable | Yes — streams to disk | Chromium-based; same capabilities as Chrome. |
| Mozilla Firefox | Current stable | Fallback — in-memory | Web Crypto and IndexedDB fully supported. No File System Access API, so large files use the in-memory fallback. |
| Apple Safari | Current stable (macOS & iOS) | Fallback — in-memory | Works via Web Crypto. Large-file streaming falls back to memory; PWA/offline support is more limited than Chromium. |
What each capability is for
- Web Crypto API — Required by all tools — this is what performs encryption, hashing, and random generation. Available in every current browser above.
- File System Access API — Used only for large-file streaming straight to disk. Chromium browsers (Chrome, Edge) only; elsewhere output uses an in-memory Blob with size limits.
- IndexedDB — Used by Local Private Notes to store encrypted notes in your browser. Supported everywhere above.
- Service Worker / PWA — Powers offline installation of the core tools. Best on Chromium; more limited on Safari/WebKit.
Safari and WebKit
The tools work in Safari and other WebKit browsers. The main difference is large files: without the File System Access API, output is assembled in memory rather than streamed to disk, so very large files are bounded by available memory (realistically around 1–2 GB before a tab is at risk). The tools warn you before you reach that point. For the biggest jobs, a Chromium browser or the offline app is the smoother path.
Keep your browser updated
Please use a current, updated browser. Outdated browsers may lack the APIs these tools rely on, and — more importantly — miss security fixes that protect the very content you are trying to keep private. If a tool reports that a capability is missing, updating the browser usually resolves it.
Prefer no network at all?
The offline app installs the core tools as a PWA so they keep working without a connection. See how it works for the bigger picture.