Squoosh

What Squoosh is

Squoosh is an open-source image compression tool built by Google and engineered for one appealing idea: the compression happens in your own browser, not on someone else's server. You load an image, choose a codec, drag a few sliders and Squoosh shows you the resulting file size live while your original stays on your machine. Because nothing is uploaded, it is effectively a privacy-safe compressor that also happens to be completely free.

The real strength of Squoosh is control. Rather than hiding the details behind a one-button optimisation, it exposes the actual codecs and their tuning knobs. You can compare WebP against AVIF against a re-encoded JPEG on the same image, watch file size update as you move the quality slider, and export exactly the compromise you want. This review is based on using Squoosh to optimise product photos, blog images and social graphics, and to compare modern formats before choosing what to deploy.

Who should use it

Squoosh appeals most to three kinds of people. Privacy-conscious users who handle confidential or client-owned images and refuse to upload them to a third-party compressor will find its local processing a genuine relief. Developers and technical designers who want to benchmark WebP against AVIF, or to understand how much quality they can trade for size, get a fast, transparent way to test. Anyone learning image optimisation benefits from seeing exactly what each setting does in real time.

It is a weaker fit if you need to process hundreds of images in a single drag-and-drop batch, since Squoosh is built around one image at a time. For that volume a scripted tool or the TinyPNG API is smoother. For single-image precision and privacy, Squoosh is hard to beat, and its open-source status means the code is auditable and yours to self-host if you want.

Pricing breakdown

There is no pricing breakdown for Squoosh because there is no price. It is free, open source and free of advertising. The project runs in the browser using WebAssembly, so all the encoding muscle is downloaded and executed locally rather than billed per use. That makes it one of the very few genuinely free tools in this directory with no account, no watermark, no daily limit and no premium tier hiding behind a paywall. If you value software you can inspect, the source is public and can be run from your own machine or a self-hosted copy, which is a meaningful privacy and longevity advantage over hosted rivals.

Hands-on notes

In daily use Squoosh is a pleasure for single files. You drop an image onto the page, and a comparison view lets you examine regions of the compressed result next to the original at full zoom. The format dropdown is where the real power lives: switching from JPEG to WebP or AVIF can cut size by half or more at an equivalent perceived quality, and the live size readout makes the trade-off concrete rather than abstract.

The main frictions are scale and speed. Squoosh handles one image per pass, so a folder of forty screenshots means forty manual runs unless you automate around it. Very large files can also take a while because encoding runs single-threaded in your browser tab. The default view is denser than TinyPNG, so a first-time user faces more knobs, but each knob is labelled clearly and the visual preview makes experimentation low-risk.

What we like

The local, server-free processing is the standout feature in a category full of opaque upload-and-pray websites. Squoosh is honest about what it does and never asks for your data. The multi-codec comparison is genuinely useful for anyone deciding between modern formats, and the live size feedback turns abstract optimisation into a visible, educational process. As a free, open-source, privacy-first tool it sets a high bar that paid competitors struggle to justify.

What to watch out for

The two real watch-outs are batch handling and browser-bound performance. Squoosh does not process folders in one action, so high-volume workflows need a different tool. It also depends on your browser's ability to run WebAssembly, which works across modern browsers but means heavy images can stutter on older hardware. There is no server-side fallback and no mobile app, so if you need on-the-go batch compression you will want a companion tool.

Verdict

Squoosh is the tool to reach for when privacy and control matter more than convenience. For confident or single-file work it is effectively unbeatable: free, local, transparent and powerful enough to teach you about modern codecs along the way. When you need guided one-click results or folder-level volume, TinyPNG and iLovePDF round out the picture. If your priority is keeping images on your own machine, Squoosh is the clear pick in this directory.

Alternatives

For those who find Squoosh fiddly or need volume, two tools cover the gap. TinyPNG delivers a guided, proven algorithm with one click and is the better default when you trust the result more than the process. iLovePDF steps in when image shrinking is part of a wider PDF and image workflow, letting you compress, convert and merge in a single suite. Squoosh stays the first choice for local, format-comparing, privacy-first work.