Visual diffs
Every page and viewport compared with a baseline, changed regions highlighted.
Visual regression testing
Screenshot your pages
Screenshot your pages
before and after a change.
See every difference.
Side By Side loads the pages you pick, on every environment and screen size, and compares each one with the version it captured before your change — so you find what moved, broke or disappeared before your clients do.
Before
After
What changed
How it works
Side By Side compares a page with its own earlier self. That earlier version only exists if you captured it first.
Side By Side does this You do this
- Add your site and pages Give it a URL for each environment, then pick the pages to watch.
- Baseline It loads your pages and stores them as they are now. before your change
- Your change Deploy, update a plugin, edit content. Nothing about your work changes.
- The same pages again Same URLs, same screen sizes, same environment. after your change
- The difference What moved, broke or disappeared, highlighted page by page.
- Review results Mark each difference as intentional or as a bug, and share the run.
The baseline has to come first. There is no way to compare a page you never captured — and nothing here compares a design against a build.
What it does
Shift detection
Content pushed down the page is reported as a shift, not as a broken page.
Console errors
JavaScript errors and failed requests from every page it loads.
Every environment
Production, staging and dev, including sites behind HTTP auth or a VPN.
Recorded interactions
Open menus or dismiss banners before the screenshot, recorded with the Chrome extension.
Alerts
An email when a run finishes, and another when it finds differences.
Before
After
What changed
FAQ
Do I need to install anything on my site?
No. It loads your pages like a visitor would.
Can it compare my design against the page that was built from it?
No. Every comparison is one page against the version of that same page it captured earlier. A mockup is not something it can load and capture, so there is nothing for it to compare the build with.
Can it compare staging against production?
No. Each environment is measured against its own baseline: a staging run is compared with an earlier staging capture, not with production. A comparison that names a baseline from a different environment is refused.
Can it compare my site with someone else's?
No. It only captures pages you have added to your own account, and only ever compares each one with its own earlier capture — never one page against a different page.
Does it test that my site still works?
Not in the sense a test suite does. It reports how every page looks and the JavaScript errors and failed requests it saw while loading them. It does not walk through a checkout, fill in a form or assert that a result is correct, so it sits alongside your functional tests rather than replacing them.
Can it capture a page only I can reach, like localhost?
Addresses that exist only on your own machine or network —
localhost, 127.0.0.1, 192.168.* — are
refused by the capture service, which will not load a private address at
all.
For those there is an experimental Chrome extension that captures the page from the browser you are already using, so the page never has to be reachable from the internet. It is still being built and cannot be switched on from your account yet.
Is there a browser extension, and which browsers does it support?
There is one, for Chrome only. It is installed by hand —
developer mode in chrome://extensions, then “Load unpacked” —
rather than from the Chrome Web Store.
Treat it as experimental. It is limited to administrators of this deployment at the moment, so it is not something you can enable yourself, and there is no Firefox or Safari version.
Does any of this change my site or its code?
No. Nothing is installed on your server, no snippet or script tag is added, and not a file or a line of your code is touched. It loads your pages the way a visitor's browser does and photographs what comes back. The extension works the same way — it reads a page your browser has already rendered.
What counts as one screenshot?
One page at one viewport. Thirty pages on three viewports is 90 screenshots per run.
How do I know when something changed?
You get an email when a run finishes, and a second one listing the biggest differences if it found any.
Who can see my screenshots?
Your captures are private. Nothing is published, listed or indexed anywhere, and no screenshot is public unless you deliberately make it so.
Members of your organisation, and anyone you give a share link to. Each run can have a read-only share link: members can create one from the run page, and the email we send when a run finishes carries one that expires after 30 days. A link opens that run's results, including the baseline screenshots it is compared against, and nothing else in your account. Revoking it from the run page switches off every link to that run, the emailed one included.
Is there a free trial?
Yes: 14 days, no credit card. Some features, like scheduled runs and the REST API, depend on the plan you choose afterwards.