WordPress

The Koryla WordPress plugin handles traffic splitting server-side using PHP — no npm, no build step, no JavaScript in the browser.

How it works

1. Plugin fetches your active experiments from the Koryla API (cached in WP transients for 5 minutes)
2. On each page request, it checks $_COOKIE for a ky_{experimentId} cookie
3. If no cookie → weighted random assignment → sets cookie via setcookie()
4. If the assigned variant is not the control → wp_redirect() to the variant URL

Everything runs in PHP during template_redirect, before WordPress renders the page.

Install

Manual:

1. Download koryla.php from the Koryla repo
2. Place it in /wp-content/plugins/koryla/koryla.php
3. Go to WordPress Admin → Plugins → Installed Plugins
4. Activate Koryla

WordPress.org listing coming soon. For now, install manually.

Configure

1. Go to WP Admin → Koryla
2. Paste your API key (sk_live_... from Koryla Dashboard → Settings → API Keys)
3. Click Save Settings

Your active experiments will appear in the panel below the settings form.

Create variants in WordPress

The plugin relies on variant URLs existing as real WordPress pages or custom routes. Typical setup:

Create the variant page in WordPress normally (or as a custom template), set it to draft or private if you don't want it discoverable via the sitemap. The plugin redirects to it server-side regardless of its publish status.

Tip: To hide variant pages from search engines, add noindex to the variant page's SEO settings (Yoast / RankMath / etc.).

Verify it's working

Visit your homepage in an incognito window. Open DevTools → Application → Cookies — you should see a ky_{experimentId} cookie set by the server.

Clear the cookie and reload several times to confirm traffic is being split between your variants.

Limitations vs edge approach

For large sites where SEO and performance are critical, pair the WordPress plugin with a Cloudflare Worker for the full edge approach.