Build the variant on your real page.
Open the page in the editor, click an element and change it, or describe the change in one sentence. Probant checks the variant before any visitor sees it.
Assistant
Changes
Automatic checks
Read the transcript
Do you need a developer to build the variant? Click on the page or describe the change in one sentence. Probant applies it to your real page and checks it before any visitor sees it.
Click on the page. The product page opens in the editor. Clicking “Ajouter au panier” selects it: rewrite its text, hide it, or ask the assistant.
Or describe the change. The assistant finds the button ([data-add-to-cart]), inserts the date just below it, and asks before touching preorders.
Checked before launch. Measured on the preview: contrast of 5.3:1 against a threshold of 4.5:1, 1.1 kB added, and 1 of 2 selectors flagged as fragile.
Try the editor on the demo store, no sign-up needed.
What the editor does.
The visuals come from the demo editor: the “Date under the button” variant of the “Estimated delivery date” test, on a product page of the fictional store.
The preview shows the page as your visitors will see it.
Probant loads your page in an inert preview: its scripts don’t run, its styles and images stay. Click an element to select it, double-click text to rewrite it, or hide it in the variant.
- Select, Browse, and side-by-side Compare A / B modes
- desktop, tablet, mobile preview
- Every change can be removed in one click
- Desktop1280 px
- Tablet768 px
- Mobile390 px
Or directly on your site, with its scripts.
A page built with JavaScript (sections loaded later, single-page app) can look empty in the preview. “Edit on my site” then opens the real page in a new tab, through a signed personal link. Content that appears later can be selected like the rest, and every change is saved to the draft.
- The same changes as in the preview, rendered the same way for visitors
- No browser extension; nothing is shown to visitors or measured
- Nothing from the page is sent to Probant except the changes you choose
Ready-made widgets, from banners to a computed delivery date.
The “Widgets” tab adds a banner, a countdown, a pop-up, a computed delivery date, a promo code, or a free-shipping bar to the variant, without writing code. Set the text, colors, position, and link, then insert it anywhere on the page. A configured widget can be reused in other tests.
- Compatible with a strict CSP
- Countdown in the site’s time zone, removed when it ends; pop-up can be closed with the keyboard
- Delivery date recalculated for each visitor: cutoff time, business days, French public holidays
- Social proof drawn from real purchases, never estimated
- Animations turned off when the visitor prefers reduced motion
- BannerHTML and stylesA one-line announcement with a link: at the top or bottom of the page, floating, or next to an element.
- Countdownon-demand moduleThe time left until a deadline, in the site’s time zone. It disappears once the deadline has passed.
- Pop-upon-demand moduleA window over the page that closes with the keyboard or the mouse, with its own display frequency.
- BadgeHTML and stylesA short label (“New”, “−20%”) next to an element on the page.
- ReassuranceHTML and stylesTwo to four short selling points, each with a check mark (shipping, returns, payment), next to an element on the page.
- Action barHTML and stylesA sentence and a button pinned to the bottom of the screen, so the main action stays within thumb’s reach while scrolling. The button follows a link or clicks the page’s real buy button (the bar hides while that button is visible).
- Delivery dateon-demand module“Delivered [date] if you order before 3 PM”: the date is computed in the visitor’s browser (cutoff time, business days, public holidays, site time zone).
- Social proofon-demand module“Bought [n] times in the last 7 days”: the exact count of purchases Probant received for this product, shown from 10 purchases. No estimates.
- Promo codeon-demand moduleText, the code, and a “Copy” button; “Copied” is announced to screen readers. At the top or bottom of the page, floating, or next to an element.
- Free shippingon-demand moduleA bar that fills up with the cart amount, read from the page without any request: “Only [remaining] left for free shipping”.
- Surveyon-demand moduleA closed question (two to six answers), a 0–10 scale, or a free-text answer, with a follow-up question and a text or image to rate (concept test). Each closed answer is measured per variant; free-text answers are redacted before they’re sent. Shown after the visitor’s consent when the workspace requires it.
The assistant writes the change from one sentence.
Describe what should change. The assistant targets an element that exists on the page, replies with changes you see right away in the preview, and lists what it did. When a detail affects the result, it asks.
- Suggested HTML is filtered: no scripts, iframes, or event handlers
- Every change can be removed
- Without the assistant, manual editing works fully
Done. The block shows under “Add to cart”, anchored to a stable selector. The date is written as is (Friday, November 13, for an order placed on Tuesday, November 10 before 3 PM), so it doesn’t update from one day to the next. For a date that follows the order time, public holidays, and your closing days, add the “Delivery date” widget from the Widgets tab instead.
- Page analyzed, buy button found: [data-add-to-cart]
- Block inserted right after it, in the page’s colors
- Date hard-coded: it doesn’t update
Preorders don’t ship within two days, so the date shown on them would be wrong. Should I exclude them?
Fragile selectors are flagged and stabilized.
A change targets an element through a selector. If that selector depends on a theme class or on the element’s position, the next store update can break it and the variant silently disappears. The editor flags it, and suggests a stable marker when it finds one.
- Preferred markers: data-* attributes and page IDs
- Tool-generated markers (React, Vue…) are skipped
- A “Stabilize” button on each fragile selector
- Inserted blockstableAfter “Ajouter au panier”
[data-add-to-cart] - StylefragileSpacing: 8px
.product-form__buttonsTheme class: it often changes when the theme is updated. Stabilize
Checks run on every change.
Probant measures the variant on the preview: the weight added to the page, the share of stable selectors, the elements found, the contrast of added text against the AA threshold (4.5:1), and the accessibility of what the variant touches or adds.
- Desktop, tablet, and mobile checked together: an element missing or hidden at one width is flagged
- Layout shift caused by the variant, computed with the CLS formula (good up to 0.1 according to web.dev)
- Images without alt text, buttons and links without an accessible name, skipped heading levels, with the WCAG criterion involved
- A change visible on arrival but applied after the script loads is flagged, with the flicker-free option
In detail.
- Changes
- Inserted block, Text changed, Style, Attribute, Hidden element, Content changed, Image replaced, Moved element. Each change applies as soon as its element exists, then on every page re-render.
- Variants
- The original and up to 4 variants per test, B to E.
- Devices
- Desktop (1,280 px), Tablet (768 px), Mobile (390 px), and the A / B comparison at the same width.
- Checks
- Added weight, stable selectors, elements found, no duplicates on a second pass, text contrast (AA threshold, 4.5:1), accessibility (WCAG 1.1.1, 4.1.2, 2.4.4, 1.3.1), elements hidden at one width, layout shift (CLS formula) at all three widths, layout shift risk on arrival.
- Test figures
- In the “Element” tab, before you build: daily visitors to the page, share of visitors who see the element, and days needed to detect a difference of 5%, 10%, or 20%. Without enough data, the editor says what is missing.
- Assistant
- Instructions in plain language; the reply comes as changes, verifiable steps and, when needed, a question with two or three options. It takes into account the brand style read from the page (colors, fonts) and, when opened from an idea, its hypothesis.
- Security
- Preview runs no scripts; assistant HTML is filtered against an allowlist; event handlers and javascript: links are rejected, down to the site script.
- On your site
- A signed link, valid for half an hour, for one draft and one variant: it launches nothing and does not touch a running test. It opens only on a domain known to the workspace. No CSP exception to add.
- Widgets
- Banner, countdown, pop-up, badge, reassurance, action bar, delivery date, social proof, promo code, free shipping, and survey. Their modules load only for visitors in the variant; only the survey sends data, its answers, after the visitor agrees when the workspace requires consent.
- Phone preview
- From the test page, a preview link opens the variant on your real site, on any device, without measuring anything. In the editor, the “Mobile” preview simulates the screen.
Frequently asked questions.
Do I need a developer?
Not for visual changes: text, style (hover and focus included), images, element position, added or hidden blocks, and ready-made widgets (banner, countdown, pop-up, delivery date, promo code…). A developer is still useful for a logic change (pricing, checkout flow); server-side assignment then lets you test it without flicker.
What happens when my theme changes?
A change anchored to a stable marker (data-* attribute, ID) survives theme updates. The editor flags the others before launch and suggests a stable marker when it finds one.
My page is built with JavaScript and the preview is empty.
Edit it on your site: the “Edit on my site” button opens the real page, with its scripts, once the Probant script is installed. The preview is still available, with nothing else to install.
Can the assistant break my page?
It only suggests reversible changes, on elements that exist on the page. Its HTML is filtered on the server, then again in the browser: no scripts, iframes, or event handlers. You see every change in the preview before launching.
Next: Test plan and duration
See this feature in the demo, on the screen this page describes, or move on to the next one.
- Open demo, no sign-up
- Free to start, no overage charges
- Database and compute in Amsterdam, with Scaleway