Preview Mode lets you see a specific experiment (and optionally a specific variant) on your live website — the same site your visitors use — as if you were a visitor who got that variant. It’s for checking how the test looks and behaves on your real site before or while it’s running.
What Preview Mode does
When you open your site with the preview parameters in the URL:
The Mida script loads only the experiment you’re previewing (and only that test’s variants).
You see the variant you chose (e.g. “Variation 1” or the control).
The browser tab title often shows something like “Preview Mode - …” so you know you’re in preview.
In the background, a small QA/preview helper may run to log what the script did (for debugging). Normal visitors don’t see this.
Important: Preview runs on your live website the same pages and the same Mida script your visitors get.
There is no separate “preview environment” or staging copy. What you see in Preview is what an end user would see if they were shown that variant.
The only difference is that you chose the variant via the URL; for a normal visitor, the variant is chosen at random (or by your targeting rules).
The rendered result, layout, copy, buttons, forms is the same. So if a variant looks correct in Preview on your live URL, that’s the same experience that variant will deliver to your users when they’re in the test.
How you usually get into Preview Mode
From the Mida app (recommended):
Open the experiment (e.g. from Experiments → Targeting → Use the eye icon)
Open preview from A/B Test Report and click on one of the screenshots
Your live site opens in a new tab with the correct URL that already includes the preview parameters.
The app builds the URL for you (your live test URL + test-preview and test-variant), so you don’t have to type them.
Using the URL yourself (advanced)
You can also preview by adding two query parameters to your site URL (the live page where Mida is loaded):
test-preview=<experiment-id> — Which experiment to show (use the experiment ID from the app).
test-variant=<variant> — Which variant to show. Use the exact variant name; if the name has spaces, use underscores in the URL (e.g. Variation_1). For the control/original, the app often uses 0 or the control label.
Example: https://yoursite.com/page?test-preview=12345&test-variant=Variation_1
So: same live page as normal, but with ?test-preview=... and ?test-variant=... and you’ll see that experiment and that variant — the same experience your end users get when they’re assigned that variant.
What happens under the hood
When the Mida script loads on your live page, it checks the URL for test-preview (and optionally test-variant).
If present, it tells the server: “I’m in preview; send me only this experiment and this variant.”
The server returns only that test’s configuration; the script applies that variant (e.g. copy, design, or custom code) so you see it on the page — the same way it would for a real visitor assigned that variant.
The preview ID and variant are also stored in the browser (e.g. in session storage and sometimes in the window name) so that if you click to another page on the same site in that tab, preview can continue to work on the next page (as long as that page also loads Mida and the params are still in the URL or restored).
So Preview Mode = “Load my live site, but force this one test and this one variant for this tab — and that’s exactly what my end users would see if they got this variant.”
Who is Preview Mode for?
You (the site owner): To check how each variant looks and behaves on your live site before or during the test.
Your team or client: You can share the preview link (URL with test-preview and test-variant) so they can see the same experience your end users get for that variant.
QA: To confirm that the right variant appears on the right pages and that buttons, forms, and links work as they will for real visitors.
Does Preview Mode affect real visitors or data?
No. Preview only runs when the URL contains the preview parameters. Normal visitors don’t have those parameters, so they get the normal experiment (random variant, normal tracking). Preview is for viewing only; it doesn’t change how the experiment runs for everyone else or how results are recorded.
Leaving Preview Mode
Close the tab and open your site again without the parameters