The Modern Website Checklist: Speed, Mobile UI, and Technical SEO

Most websites lose visitors before a single word of copy gets read. Slow load times, a clunky mobile layout, or a technical SEO gap will quietly cap your traffic and conversions regardless of how good the design or content is. Here’s the checklist we run through before calling any site launch-ready.

1. Speed

Core Web Vitals

Google measures loading speed, interactivity, and visual stability as ranking and user-experience signals. A site that fails these checks loses both search visibility and visitors, since most people abandon a page that takes more than a few seconds to load.

Image and Asset Optimization

Uncompressed images, unminified scripts, and unused plugins are the most common causes of slow load times. Converting images to modern formats and lazy-loading anything below the fold usually delivers the biggest speed gains for the least effort.

2. Mobile UI

Design for Thumbs, Not Cursors

Tap targets need real spacing, forms need to work with a mobile keyboard, and navigation needs to collapse cleanly. Most traffic today arrives on a phone, so the mobile layout isn’t a secondary version of the site — for most visitors, it is the site.

Test on Real Devices

A responsive preview in the browser doesn’t catch everything. Actual devices reveal issues with tap accuracy, font scaling, and viewport quirks that only show up outside a desktop simulator.

3. Technical SEO

Clean Heading Hierarchy

Every page should have one H1 that states what the page is about, followed by H2s and H3s that organize the content logically. Search engines and screen readers both rely on this structure to understand a page.

Meta Titles, Descriptions, and Alt Text

Unique meta titles and descriptions on every page improve click-through from search results, and descriptive alt text on images improves both accessibility and image search visibility.

Sitemap, Robots.txt, and Indexing

An up-to-date XML sitemap and a robots.txt file that isn’t accidentally blocking key pages are the baseline for making sure search engines can find and index your content in the first place.

Run the Checklist Before You Launch

Speed, mobile UI, and technical SEO aren’t polish — they’re the infrastructure everything else sits on. Cecil Turtle audits sites against exactly this checklist before any campaign goes live, because no amount of ad spend fixes a site visitors can’t use.