Split URL testing with different page versions

Split URL Testing (Different Page Versions)

Split URL testing is a variant of A/B testing where control and variant are hosted on different URLs. Unlike standard A/B testing (one page, DOM changes via JS), Split URL is used when versions are fundamentally different and impractical to keep both in one template.

When to Use Split URL Testing

• Completely new page design vs old version
• Comparing two different landing pages
• Testing new checkout flow vs old one
• Comparing different CMS/platforms for one page
• Landing page on different technologies (React SPA vs static HTML)

Setup via nginx

# Random traffic split 50/50
split_clients "${remote_addr}${http_user_agent}${date_gmt}" $split_variant {
    50% "variant";
    *   "control";
}

server {
    listen 80;
    server_name company.com;

    location = /landing {
        if ($split_variant = "variant") {
            rewrite ^ /landing-v2 last;
        }
        # control - stays on /landing
    }

    # Persist variant in cookie for consistency
    location = /landing {
        if ($cookie_ab_landing = "variant") {
            rewrite ^ /landing-v2 last;
        }
        if ($cookie_ab_landing = "control") {
            # keep
        }
        # Assign and redirect
        add_header Set-Cookie "ab_landing=$split_variant; Path=/; Max-Age=2592000; SameSite=Lax";
    }
}

Setup via Cloudflare Workers

addEventListener('fetch', event => {
  event.respondWith(handleSplitTest(event.request))
})

const CONTROL_URL = 'https://company.com/checkout-v1'
const VARIANT_URL = 'https://company.com/checkout-v2'
const TEST_PATH = '/checkout'

async function handleSplitTest(request) {
  const url = new URL(request.url)

  if (url.pathname !== TEST_PATH) {
    return fetch(request)
  }

  // Check cookie for stickiness
  const cookie = request.headers.get('Cookie') || ''
  const cookieMatch = cookie.match(/split_checkout=([^;]+)/)

  let variant = cookieMatch ? cookieMatch[1] : null

  if (!variant) {
    // Deterministic assignment by IP + UA
    const key = request.headers.get('CF-Connecting-IP') + request.headers.get('User-Agent')
    const hash = await hashKey(key)
    variant = (hash % 2 === 0) ? 'control' : 'variant'
  }

  const targetUrl = variant === 'variant' ? VARIANT_URL : CONTROL_URL
  const response = await fetch(targetUrl, request)

  // Clone response to add cookie
  const newResponse = new Response(response.body, response)
  if (!cookieMatch) {
    newResponse.headers.append('Set-Cookie',
      `split_checkout=${variant}; Path=/; Max-Age=2592000; SameSite=Lax`)
  }

  return newResponse
}

Canonical Tags for SEO Duplicate Prevention

Important: two URLs with similar content without canonical → duplicate issue:

<!-- /landing-v2 (test version) -->
<link rel="canonical" href="https://company.com/landing">

<!-- Or if test is temporary, add noindex on variant -->
<meta name="robots" content="noindex, follow">

If both URLs should temporarily be indexed — use rel="alternate":

<link rel="alternate" href="https://company.com/checkout-v2">

Analytics Tracking

// On both page versions — send event with variant
const variant = getCookieValue('split_checkout') || 'control'

// GA4 Custom dimension
gtag('set', 'user_properties', {
  split_test_checkout: variant
})

// Or as event parameter
gtag('event', 'page_view', {
  split_test: 'checkout_redesign',
  split_variant: variant
})

// On conversion
gtag('event', 'purchase', {
  transaction_id: orderId,
  value: total,
  split_test: 'checkout_redesign',
  split_variant: variant
})

-- GA4 BigQuery: conversion by Split URL test variants
SELECT
  user_properties.value.string_value AS variant,
  COUNT(DISTINCT user_pseudo_id) AS users,
  COUNT(DISTINCT CASE WHEN event_name = 'purchase' THEN user_pseudo_id END) AS converters,
  ROUND(COUNT(DISTINCT CASE WHEN event_name = 'purchase' THEN user_pseudo_id END) * 100.0 /
        COUNT(DISTINCT user_pseudo_id), 2) AS cvr
FROM `project.analytics.events_*`,
UNNEST(user_properties) AS user_properties
WHERE user_properties.key = 'split_test_checkout'
GROUP BY variant;

Post-Test: Promoting the Winner

If variant won — replace control and remove split:

# Remove split, serve v2 to everyone
location = /checkout {
    rewrite ^ /checkout-v2 last;
}
# Or rename /checkout-v2 to /checkout

Update canonical and remove noindex/alternate tags.

Delivery Time

Setting up Split URL test with cookie stickiness, analytics, and SEO protection — 1–2 business days.