WordPress

The Splitlab plugin adds the Splitlab engine to every page of your WordPress site. You don't need to edit your theme. If you run WooCommerce, the same plugin can also report orders as test revenue.

Requires	WordPress 5.7 or later, PHP 7.4 or later
WooCommerce	Optional. Classic and block checkout, and High-Performance Order Storage (HPOS), are supported
Plugin slug	splitlab

Install

1. In your WordPress admin, go to Plugins → Add New and search for Splitlab. Click Install Now, then Activate.
2. Go to Settings → Splitlab.
3. Paste your project key and click Save Changes. The project key is the data-project-key value in the dashboard under Install / SmartCode, on the Wordpress tab.
4. Verify the install.

Nothing is printed on your pages until a project key is saved.

Settings

All settings are under Settings → Splitlab.

Setting	Default	What it does
Project key	empty	Required. Which Splitlab project the site belongs to. Only letters, digits, _ and - are kept.
Anti-flicker	On	Hides the page until the engine has applied the visitor's variant, so they never see the original first.
Reveal anyway after	3000 ms	If the engine has not loaded by then, the page is shown anyway. Accepts 500 to 10000 ms.
Server API key	empty	Only needed for WooCommerce revenue.
Environment	Production	Leave on Production. Staging points at Splitlab's internal test servers.

What the plugin adds to your pages

The plugin prints two scripts as the first thing in <head>, ahead of your theme's styles and scripts:

1. The anti-flicker script (when it is on). It sets body { opacity: 0 } and reveals the page when the engine calls window.rmfk(), or after the timeout.
2. The engine, loaded async from https://cdn.splitlab.io/cdn/engine.js, with your project key in data-project-key.

This is the same code as the install snippet, so everything on that page about consent, options and verifying applies here too.

Caching and optimisation plugins

Plugins that defer, delay or combine JavaScript break this setup in one of two ways:

• If the anti-flicker script is delayed, visitors briefly see the original page before the variant appears.
• If the engine is delayed until the visitor interacts, the page stays blank until the anti-flicker timeout.

The plugin marks both scripts so the common optimisers leave them alone:

Optimiser	How the plugin opts out
WP Rocket (Delay JavaScript execution)	nowprocket attribute
LiteSpeed Cache	data-no-optimize="1" and data-no-defer="1"
Cloudflare Rocket Loader	data-cfasync="false"
Autoptimize	Wrapped in <!--noptimize--> … <!--/noptimize-->

If you use a different optimiser and see flicker or a blank page, exclude mvt-anti-flicker, mvt-engine-script and cdn.splitlab.io in its JavaScript settings.

Cookie consent

If your Splitlab project requires cookie consent, the engine stores nothing until the visitor grants it. The plugin adds nothing of its own on top of this. See the install snippet for how consent is signalled to the engine.

Troubleshooting

Symptom	Likely cause	Fix
Verify finds no snippet	Page cache still serving old pages	Purge the cache, then verify again
Verify finds no snippet	Project key not saved	Check Settings → Splitlab
Original page flashes before the variant	An optimiser is delaying the anti-flicker script	Exclude it as described above
Page stays blank for a few seconds	An optimiser is delaying the engine	Exclude it as described above, or lower Reveal anyway after
Snippet appears twice	The snippet was also pasted into a header plugin or the theme	Remove the pasted copy; the plugin is enough

Uninstall

Deactivating the plugin removes the snippet from your pages. Deleting it under Plugins also deletes its settings. Order notes and order data written for WooCommerce revenue stay on your orders.