PUBLIC REPOSITORY · MIT LICENSED

An open-source image compressor you can verify.

Zestkit says your images stay in the browser. You do not have to take that sentence on trust: trace the processing path, inspect every network boundary, or run the same code yourself.

View source on GitHub Try the live compressor

Local processing tracezestkit.cc

01Read locallyThe browser reads the file you choose; the page does not post it to an upload endpoint.
02Encode in a workerCompression and conversion run away from the main interface so the page stays responsive.
03Measure real bytesZestkit checks the encoded Blob rather than predicting a result from a quality percentage.
04Download locallyA temporary object URL connects the verified result directly to your browser download.

upload endpoint: not required

VERIFY THE CLAIM

Follow the code, not the promise.

The public repository is useful because it connects a privacy statement to concrete implementation. Start with the file boundary, continue through the worker, and finish at the measured Blob that becomes your download.

Compression worker

web/src/workers/compress-image.worker.ts

Follow the quality search, dimension reduction, and final byte-limit check away from the main UI thread.

Validation and job control

web/src/lib/image-compression.ts

Inspect file signatures, static-image checks, worker messages, cancellation, and result verification.

Format conversion worker

web/src/workers/convert-image.worker.ts

See how supported images are decoded and exported locally as JPG, PNG, or WebP.

WHY OPEN SOURCE MATTERS HERE

Built for evidence, not a trust badge.

No hidden upload path

Inspect the file flow and confirm that compression does not depend on a Zestkit image-storage service.

Verified output size

Read the final Blob-size check that runs before a successful compressed result is exposed for download.

Self-hostable

Run the same interface and workers locally or deploy your own copy without creating a Zestkit account.

MIT licensed

Use, study, modify, and distribute the project under a short, permissive open-source license.

Run Zestkit locally.

The repository contains one Next.js application in the web directory. No database, account system, or image-processing API is required for the current tools.

Terminalthree commands

git clone https://github.com/Barry5753/Zestkit.git
cd Zestkit/web
pnpm install && pnpm dev

Open localhost:3000/compress-image-to-100kb

USE OR CONTRIBUTE

Take a closer look.

Try the live tools first, read the code path that matters to you, or open a focused issue when you find a reproducible problem.

Try the format converter View GitHub issues

Is the whole image-processing path open source?+

Yes. The browser interface, validation code, compression worker, conversion worker, and final result checks are all available in the public repository.

Can I run Zestkit on my own computer?+

Yes. Clone the repository, install the web app dependencies with pnpm, and start the local Next.js development server. The exact commands are shown on this page and in the README.

Can I reuse the code in another project?+

Zestkit is released under the MIT License. You may use, copy, modify, and distribute it under the terms in the repository's LICENSE file.