Website basics AI checks first: HTTPS, one domain, fast on mobile

Why it matters

AI assistants often look things up in search engines before they answer. Google says a page must be in its index to appear as a link in AI Overviews and AI Mode, and that the usual search best practices, including "a great page experience", still apply. Microsoft Copilot sends search queries to Bing and writes its answer from what Bing returns.

So the basics that help search engines read and trust your website also help the assistants that draw on them. Three of them are quick to check:

• A secure address (HTTPS). Google asks "Are your pages served in a secure fashion?" in its own page experience checklist, and prefers HTTPS pages over HTTP copies.
• One address for the whole website. If yourcompany.lu and www.yourcompany.lu both show the same pages, search engines see two copies and have to guess which one is yours.
• Fast on a phone. Google indexes the mobile version of your pages, and its ranking systems use Core Web Vitals, its three speed and stability measures.

None of this makes an assistant recommend you. No AI provider says it ranks businesses by speed. These checks remove reasons for a search engine to read the wrong copy of your website, or to read it less well.

Illustration with a fictional business.

This guide is short on purpose. To check that Google and Bing have stored your pages, and to fix page titles, follow Guide 03: Get found by Google and Bing.

Reference

Words you will meet

Before you start

Have these ready

• Your website address, and a decision: with www. or without. Either is fine. If you are unsure, keep the one already printed on your business cards and used in your links.
• The contact of your hosting company or developer. Redirects are set on the server or in the hosting panel, not in the page text.
• Two pages to test for speed: your home page and your most important service page.
• Optional, for developers: a Terminal window (Mac or Linux) to run curl.

Steps

Check and fix the three basics

1. Type the four versions of your address

   In a private browser window, type each of these, with your own domain, and look at the address bar once the page has loaded:

   • http://yourcompany.lu
   • http://www.yourcompany.lu
   • https://yourcompany.lu
   • https://www.yourcompany.lu

   Good: all four end on exactly the same address, starting with https://. Needs fixing: any of them stays on http://, shows a security warning, shows an error, or stays on its own version while showing your pages.

   Then try one inner page the same way, for example http://yourcompany.lu/contact. It should land on the same inner page in the secure version, not on your home page.

2. Developers: confirm the redirect is a 301, in one step

   A browser hides what kind of redirect happened. curl -sI shows the server's answer: the status line and the Location it points to. Here is our own website, checked on 24 October 2026:

   Terminal · letzscale.com, 24 October 2026Copy

   $ curl -sI http://letzscale.com
   HTTP/1.1 301 Moved Permanently
   Location: https://letzscale.com/
   
   $ curl -sI https://www.letzscale.com
   HTTP/1.1 301 Moved Permanently
   Location: https://letzscale.com/
   
   $ curl -sI http://www.letzscale.com/pricing
   HTTP/1.1 301 Moved Permanently
   Location: https://letzscale.com/pricing

   We chose the address without www. Every other version answers 301 Moved Permanently and points straight to https://letzscale.com, in one step, keeping the rest of the address (/pricing). That is what you are looking for. Watch out for 302 or 307 (temporary), and for chains where one redirect leads to another before the final page.

3. Ask for a permanent, server-side redirect

   Google recommends "a permanent server-side redirect whenever possible". Send your host or developer this request, with your chosen address:

   Message to your host or developerCopy

   Please make https://www.yourcompany.lu the only address of our website:
   1. A valid HTTPS certificate on yourcompany.lu and www.yourcompany.lu.
   2. A server-side 301 redirect from http:// and from the other version
      (with or without www) to https://www.yourcompany.lu,
      in one step, keeping the rest of the address (/contact stays /contact).
   3. Canonical tags and the sitemap use https://www.yourcompany.lu only.

   Many hosting panels and website builders have a switch for "force HTTPS" and for the main domain. If yours does not, the redirect is a few lines in the server configuration. On an Nginx server, it follows the pattern in Nginx's own documentation:

   Developers · Nginx, plain-http requestsCopy

   server {
       listen       80;
       server_name  yourcompany.lu www.yourcompany.lu;
       return       301 https://www.yourcompany.lu$request_uri;
   }

   This sends both http:// versions to the secure www address. The secure version without www needs a similar block on port 443, with your certificate, which your host usually sets up. Google advises keeping redirects in place for as long as possible, generally at least a year.

4. Look for mixed content

   Open your home page on its https:// address. Open the browser's developer tools and choose the Console tab. MDN, the browser makers' reference, says the console shows a warning whenever mixed content is upgraded or blocked. Reload the page and look for messages that mention "Mixed Content" and an address starting with http://.

   The fix is to change those addresses to https://, or to a relative address for files on your own website. On a website builder, this is often an old image or embed pasted in years ago: replace it in the editor.

5. Run PageSpeed Insights on two pages

   Open pagespeed.web.dev, paste your home page address and click Analyze. Read the Mobile results first. Then do the same for your main service page.

   pagespeed.web.dev · Mobile

   

   The top part shows how real visitors experienced the page over the last 28 days. Google calls this field data. The page passes the Core Web Vitals Assessment when 75% of visits meet the "good" level for each measure:

   Measure	What it means	Good	Poor
   LCP Largest Contentful Paint	How long until the main content, often the big top image, appears	2.5 seconds or less	Over 4 seconds
   INP Interaction to Next Paint	How fast the page reacts when someone taps or clicks	200 milliseconds or less	Over 500 milliseconds
   CLS Cumulative Layout Shift	How much the page jumps around while it loads	0.1 or less	Over 0.25

   Small websites often have too few visits for field data. PageSpeed Insights then uses data for the whole website, or shows none. In that case, read the Performance score below it. It comes from a single simulated visit: 90 to 100 is good, 50 to 89 needs improvement, 0 to 49 is poor. It changes a little from one run to the next.

6. Fix images first

   On most small business websites, the slow part is a large photo at the top of the page. Google's web.dev guide says the main content that loads is usually an image or a web font, and lists these fixes:

   • Right size. Do not upload a 5,000-pixel camera photo for a space 1,200 pixels wide.
   • Compress it, and use a modern format such as WebP or AVIF where your website supports it.
   • Developers: never lazy-load the main top image, and give it fetchpriority="high".

   Run PageSpeed Insights again after the change. The suggestions further down the report name the files that slow the page; send them to your developer if they concern code rather than images.

Check it worked

Confirm one secure, fast address

Repeat step 1 in a new private window. If you have Google Search Console, its Core Web Vitals report shows how your pages do over time. Setup is in Guide 03.

Common mistakes

What usually goes wrong

• A temporary redirect. A 302 or 307 tells Google the move is not final, so the old address may stay in results. Use 301 or 308.
• Redirect chains. http://yourcompany.lu → http://www.yourcompany.lu → https://www.yourcompany.lu. Go straight to the final address in one step.
• Sending every page to the home page. Keep the rest of the address so /contact lands on /contact.
• Half-finished HTTPS. The redirect works but canonical tags, the sitemap or internal links still say http://. Update them too.
• Lazy-loading the main photo. It makes the most important image wait. web.dev says never to lazy-load it.
• Chasing a perfect score. Google itself says a perfect score just for search may not be worth the effort. Aim for "good" on the pages people actually visit.