About FormatWave
Image conversion should not require handing your photos to a stranger’s server.
FormatWave is a small set of image converters built on a simple premise: the browser is now capable enough to do this work locally. HEIC decoding used to require native code or a server. With WebAssembly it runs in a tab, in about a second, on a laptop that costs less than the subscription to a competing converter.
What that changes
- Privacy is structural, not a promise. There is no upload endpoint, so there is nothing to retain, delete, or leak.
- No queue. Conversion time is your CPU, not someone else’s backlog.
- No account. Nothing to cancel, no email to hand over.
- Offline. Once cached, the converter works without a connection.
How it works
HEIC files are decoded with libheif compiled to WebAssembly, inside a Web Worker so the interface stays responsive. Decoded pixels are drawn to a canvas, resized if you asked, and re-encoded as JPG, PNG or WebP. Re-encoding drops the EXIF block, which is why metadata — including GPS — does not survive.
The site is static HTML and JavaScript. There is no application server, no database, and no storage bucket.
Limits we are honest about
- 100 files per batch, 100 MB per file.
- We cannot produce HEIC output — browsers cannot encode HEVC.
- Very wide-gamut photos are converted to sRGB, which can shift saturated colours slightly.
- Mobile browsers have tighter memory limits; keep batches under about 30 on a phone.
Contact
Questions, bugs, format requests: hello@formatwave.com. If a file fails to convert, sending us the file (or its camera model) is the fastest way to get it fixed.