Workflow6 min read·Updated

How to Convert Images Without Uploading Them

If a site asks you to 'drop files' and then a progress bar says 'uploading', you picked the wrong tool. Local conversion uses the browser's encoder. You can confirm in DevTools: there is no image POST to a server.

How to tell

Open the Network tab. Convert a photo. If you see a multi-megabyte upload, leave. On this site the heavy work is local; we only ping tiny analytics if you allow them.

Why it matters

  • GDPR and contracts.
  • Unreleased products.
  • School and family photos.

How to do it

  1. Use this converter or Squoosh for single files.
  2. For automation, run cwebp on your machine or a VPC.
  3. Never use a random converter for client work.
Convert a batch in your browser. Nothing is uploaded.
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Put it into practice

Convert your images to WebP right now, free and privately in your browser.

Open the converter

Frequently asked questions

No. After you choose to pay, converted files can be stored in your browser so they survive the Stripe return. Still on your disk.

The API is server-side by definition. Use it for pipelines, not for NDA drops on a website.

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