Your first decision should be selecting the correct file format for the job. This directly impacts file size and quality.

A. Traditional Formats

• JPEG (.jpg): Best for photographs and images with lots of colour blending and gradients. It uses a lossy compression method, which permanently removes some data to reduce file size.

• PNG (.png): Best for graphics, logos, and images that require transparency. It uses a lossless compression method, meaning no data is lost, but the file size is often significantly larger than JPEG.

• GIF (.gif): Only used for simple animations and should be avoided for static images.

B. Next-Gen Formats: WebP

WebP is the modern standard, offering superior compression and quality characteristics compared to JPEG and PNG.

• Key Advantage: WebP can achieve approximately 25–35% smaller file sizes than JPEG for the same visual quality. It supports both lossy compression (like JPEG) and transparency (like PNG).

• Actionable Strategy: Whenever possible, use WebP. Modern browsers (Chrome, Edge, Firefox, Safari) support it, and Google actively recommends it.

Phase 1: Data Integrity Checks (Ensure You Can Measure Success)

1. Primary Analytics Tag Verification

Action & Rationale: Ensure your Google Analytics (UA/GA4) or other primary tracking code is installed on every single page.

Evergreen Tip: Use the developer console (Network tab) or the Google Tag Assistant extension to verify the tag is firing correctly across key pages.

2. Conversion Tracking Validation

Action & Rationale: Conduct a full, live test conversion (e.g., submit a contact form, complete a purchase) and verify that the corresponding Goal/Event registers correctly in your analytics platform.

Evergreen Tip: Remember to exclude your own IP address from the analytics view before the launch to keep your team’s test data clean.

3. Paid Media Tracking Pixels

Action & Rationale: Confirm all necessary paid media pixels (Google Ads Conversion Tag, Meta Pixel, LinkedIn Insight Tag, etc.) are installed correctly and are passing back the correct conversion value or data layers.

Evergreen Tip: Use the platform’s specific helper extension (e.g., Meta Pixel Helper) to instantly verify the tag status on the live domain.

Phase 2: Indexing Control Checks (Ensure Search Engines Understand You)

4. Robots.txt Review

Action & Rationale: If the old site or staging site had Disallow: / to block search engines, ensure this line is removed or correctly configured on the live domain.

Evergreen Tip: Your robots.txt should only block non-essential areas (like internal search results, admin pages), not important SEO pages.

5. Canonical Tags Verification

Action & Rationale: Every important page should have a canonical tag that points back to itself. This prevents duplicate content issues.

Evergreen Tip: Check that the canonical tag is using the final, live URL structure (e.g., https://www.yourdomain.co.uk/...) and not a staging URL.

6. Redirection Mapping Audit

Action & Rationale: For redesigned sites, verify that every significant URL from the old site (especially those with backlinks) is permanently redirected (301 status) to the most relevant URL on the new site.

Evergreen Tip: Use a bulk redirect checker tool to audit your primary redirection map before and immediately after launch.

7. XML Sitemap Submission

Action & Rationale: Create an updated XML sitemap that contains only the pages you want Google to index. Submit this sitemap to Google Search Console and Bing Webmaster Tools.

Evergreen Tip: Ensure your sitemap is referenced correctly in your robots.txt file for quicker discovery by search engines.

Phase 3: Performance & User Experience (Ensure Optimal Delivery)

8. Mobile Responsiveness Testing

Action & Rationale: Check the rendering of your most important pages (homepage, key landing pages, checkout) on multiple devices and screen sizes. Content should be readable without zooming.

Evergreen Tip: Use Google’s Mobile-Friendly Test tool as a quick, free sanity check before the final launch.

9. Basic Page Speed Audit

Action & Rationale: Perform a quick check using tools like Google PageSpeed Insights on your homepage and a few key content pages. Look for critical errors related to image size or rendering-blocking resources.

Evergreen Tip: Even if not perfect, identify any glaring issues that can be fixed within the first 48 hours of launch.

10. Browser Consistency Check

Action & Rationale: Ensure the site loads and functions correctly on Chrome, Firefox, Safari, and Edge. Minor bugs across browsers can significantly hurt conversion rates.

Evergreen Tip: Pay close attention to CSS styles and JavaScript functionality, especially form submissions, which can vary between browser engines.