Shrink files. Nothing leaves your browser.
wandlr is a small, free tool to compress and convert images and PDFs. Everything runs locally, in your browser — no uploads, no accounts, no tracking, no server storage.
Live at wandlr.de.
The easiest way to trust a "we don't upload your files" claim is to be able to check it yourself:
- Open your browser's network tab while converting a file — it stays empty.
- The entire source is right here in this repository. No build step, no bundler, no minification of the app code — what you read is what runs.
- Images are processed with the browser's native Canvas API (plus
libheif-js for HEIC
input, since browsers can't decode that natively). PDFs use two well-known
open-source libraries (pdf.js and
pdf-lib). All three are vendored in
vendor/, loaded once, then run entirely offline in memory.
- Images — compress and convert between JPEG, PNG and WebP (including HEIC input from iPhone photos), with a quality slider and a live before/after size comparison. Multiple files at once.
- PDF — compress a PDF by re-rendering each page as an image at your chosen quality. This trades selectable/searchable text for a smaller file — a deliberate, disclosed trade-off, not a limitation we're hiding.
- Installable & offline — wandlr is a PWA. Install it from your browser and it keeps working without an internet connection after the first visit.
There's no build step. Serve the folder with any static file server and open it, for example:
python3 -m http.server
Plain HTML, CSS and JavaScript (ES modules). No framework, no bundler.
vendor/ contains the pre-built browser bundles of pdf.js (Apache-2.0),
pdf-lib (MIT) and libheif-js (LGPL-3.0), used as-is. A service worker
(sw.js) caches the app shell for offline use, and expands its cache with
the PDF/HEIC engines the first time each is actually used.
MIT — see LICENSE.