Technical SEO Checklist for New Websites: Complete 2025 Guide

Technical SEO is the foundation that determines whether search engines can properly access, crawl, and index your website. Get this wrong, and your brilliant content won't rank no matter how good it is.

I've launched dozens of websites and seen how proper technical SEO setup makes the difference between ranking within weeks versus struggling for months. This checklist covers everything you need to verify before and after launching a new website.

Why Technical SEO Matters

Before technical SEO: Search engines struggle to find pages, site loads slowly, mobile users bounce, pages don't get indexed.

After technical SEO: Search engines efficiently crawl your site, pages load fast, users have a smooth experience, content gets indexed and ranks.

Bottom line: Technical SEO removes the obstacles preventing your website from ranking. It's not glamorous, but it's essential.

Pre-Launch Technical SEO Checklist

1. Indexing and Crawlability

Verify robots.txt is configured correctly:

Your robots.txt file tells search engines which pages they can and cannot crawl.

Location: yoursite.com/robots.txt

Basic robots.txt for new sites:

User-agent: *
Allow: /

Sitemap: https://yoursite.com/sitemap.xml

Common mistake: Accidentally blocking important pages:

# DON'T DO THIS unless you mean it
User-agent: *
Disallow: /

This blocks your entire site from search engines.

Check your robots.txt:

Visit yoursite.com/robots.txt
Ensure important pages aren't blocked
Include sitemap location
Remove any staging/development blocks before launch

Check meta robots tags:

Individual pages can have meta robots tags that control indexing:

<!-- This prevents the page from being indexed -->
<meta name="robots" content="noindex, nofollow">

<!-- This allows indexing (or simply omit the tag) -->
<meta name="robots" content="index, follow">

What to check:

Remove noindex from pages you want indexed
Keep noindex on pages like privacy policy, thank you pages, admin areas
Verify important pages have no blocking directives

Common culprits:

Staging site directives left in production
CMS plugins adding unwanted noindex tags
Template defaults blocking pages

2. XML Sitemap

Your sitemap helps search engines discover all your important pages.

Requirements:

Located at yoursite.com/sitemap.xml
Lists all important pages
Updates automatically when content changes
Includes last modification dates
Properly formatted XML

Basic sitemap structure:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://yoursite.com/</loc>
    <lastmod>2025-11-20</lastmod>
    <changefreq>weekly</changefreq>
    <priority>1.0</priority>
  </url>
  <url>
    <loc>https://yoursite.com/about</loc>
    <lastmod>2025-11-15</lastmod>
    <changefreq>monthly</changefreq>
    <priority>0.8</priority>
  </url>
</urlset>

For Next.js sites:

Next.js 13+ can generate sitemaps automatically:

// app/sitemap.ts
import { MetadataRoute } from 'next'

export default function sitemap(): MetadataRoute.Sitemap {
  return [
    {
      url: 'https://yoursite.com',
      lastModified: new Date(),
      changeFrequency: 'weekly',
      priority: 1,
    },
    {
      url: 'https://yoursite.com/about',
      lastModified: new Date(),
      changeFrequency: 'monthly',
      priority: 0.8,
    },
  ]
}

WordPress sites:

Use Yoast SEO or Rank Math plugins
They generate sitemaps automatically

After creating your sitemap:

Submit to Google Search Console
Submit to Bing Webmaster Tools
Add to robots.txt

3. Site Speed and Core Web Vitals

Google uses page speed as a ranking factor.

Three key Core Web Vitals metrics:

1. Largest Contentful Paint (LCP)

Measures loading performance
Target: under 2.5 seconds
What it measures: when main content loads

2. First Input Delay (FID)

Measures interactivity
Target: under 100 milliseconds
What it measures: time until page responds to user interaction

3. Cumulative Layout Shift (CLS)

Measures visual stability
Target: under 0.1
What it measures: unexpected layout movements

How to test:

Google PageSpeed Insights: pagespeed.web.dev
Chrome DevTools Lighthouse
Search Console Core Web Vitals report

Common fixes:

Improve LCP:

<!-- Preload critical resources -->
<link rel="preload" as="image" href="/hero-image.jpg">

<!-- Optimize images -->
<img src="image.jpg"
     alt="Description"
     width="800"
     height="600"
     loading="lazy">

For Next.js use the Image component:

import Image from 'next/image'

<Image
  src="/hero.jpg"
  alt="Description"
  width={800}
  height={600}
  priority // For above-fold images
/>

Reduce CLS:

Always specify image dimensions
Reserve space for ads/embeds
Avoid inserting content above existing content
Use CSS to reserve space for dynamic content

/* Reserve space for an image that loads later */
.image-container {
  aspect-ratio: 16 / 9;
  width: 100%;
}

General speed improvements:

Minimize JavaScript
Defer non-critical JS
Use a CDN for static assets
Enable compression (Gzip/Brotli)
Optimize images (WebP format when possible)
Minimize CSS
Use browser caching

4. Mobile Optimisation

Over 60% of searches happen on mobile. Google uses mobile-first indexing.

Essential mobile checks:

Responsive design:

Site adapts to all screen sizes
Text readable without zooming
Buttons large enough to tap
No horizontal scrolling

Mobile testing tools:

Google Mobile-Friendly Test: search.google.com/test/mobile-friendly
Chrome DevTools device mode
Test on real devices

Mobile viewport meta tag:

<meta name="viewport" content="width=device-width, initial-scale=1.0">

This should be in your <head> section.

Mobile usability issues to avoid:

Flash content (obsolete)
Tiny text (minimum 16px)
Links too close together
Content wider than screen
Unplayable video formats

Mobile speed matters more:

Mobile users expect fast loading
Mobile connections often slower
Optimize images aggressively for mobile
Minimize mobile-specific resources

5. HTTPS and Security

HTTPS is a ranking factor. All new sites must use HTTPS.

Check your SSL certificate:

Visit your site with https://
Look for padlock icon in browser
No mixed content warnings
Certificate valid and not expired

How to implement HTTPS:

For most hosting:

Purchase SSL certificate (or use free Let's Encrypt)
Install certificate on server
Update all internal links to HTTPS
Add 301 redirects from HTTP to HTTPS
Update sitemap URLs to HTTPS
Update Google Search Console property

301 redirect from HTTP to HTTPS:

Apache (.htaccess):

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

Nginx:

server {
    listen 80;
    server_name yoursite.com;
    return 301 https://$server_name$request_uri;
}

Check for mixed content:

All resources (images, scripts, CSS) must load via HTTPS
Browser console will show mixed content warnings
Fix by updating URLs to HTTPS

6. URL Structure

Clean, descriptive URLs help search engines and users.

Good URL structure:

✓ yoursite.com/services/web-design
✓ yoursite.com/blog/technical-seo-checklist
✓ yoursite.com/about

Bad URL structure:

✗ yoursite.com/page?id=123&ref=abc
✗ yoursite.com/index.php?page=services
✗ yoursite.com/blog/2025/11/20/post-12345

URL best practices:

Use hyphens (not underscores) to separate words
Keep URLs short and descriptive
Include target keyword when natural
Use lowercase letters
Avoid special characters
Remove unnecessary words (a, the, and, etc.)

Examples:

Poor: yoursite.com/blog/this-is-a-post-about-the-technical-seo Better: yoursite.com/blog/technical-seo-checklist

Canonical URLs:

Tell search engines which version of a page is primary:

<link rel="canonical" href="https://yoursite.com/page">

Use canonical tags when:

Same content accessible via multiple URLs
HTTP and HTTPS versions exist
www and non-www versions exist
URL parameters create duplicates

7. Structured Data (Schema Markup)

Help search engines understand your content with structured data.

Common schema types for new websites:

Organization schema (for your homepage):

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Organization",
  "name": "Your Business Name",
  "url": "https://yoursite.com",
  "logo": "https://yoursite.com/logo.png",
  "description": "Brief description of your business",
  "address": {
    "@type": "PostalAddress",
    "streetAddress": "123 Main Street",
    "addressLocality": "Bristol",
    "postalCode": "BS1 5NE",
    "addressCountry": "GB"
  },
  "contactPoint": {
    "@type": "ContactPoint",
    "telephone": "+44-123-456-7890",
    "contactType": "customer service"
  },
  "sameAs": [
    "https://www.facebook.com/yourpage",
    "https://www.linkedin.com/company/yourcompany",
    "https://twitter.com/yourhandle"
  ]
}
</script>

Article schema (for blog posts):

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Article",
  "headline": "Your Article Title",
  "description": "Brief description of the article",
  "image": "https://yoursite.com/article-image.jpg",
  "author": {
    "@type": "Person",
    "name": "Author Name"
  },
  "publisher": {
    "@type": "Organization",
    "name": "Your Site Name",
    "logo": {
      "@type": "ImageObject",
      "url": "https://yoursite.com/logo.png"
    }
  },
  "datePublished": "2025-11-20",
  "dateModified": "2025-11-20"
}
</script>

Breadcrumb schema (for navigation):

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "BreadcrumbList",
  "itemListElement": [{
    "@type": "ListItem",
    "position": 1,
    "name": "Home",
    "item": "https://yoursite.com"
  },{
    "@type": "ListItem",
    "position": 2,
    "name": "Blog",
    "item": "https://yoursite.com/blog"
  },{
    "@type": "ListItem",
    "position": 3,
    "name": "Technical SEO",
    "item": "https://yoursite.com/blog/technical-seo-checklist"
  }]
}
</script>

Test your structured data:

Google Rich Results Test: search.google.com/test/rich-results
Schema.org Validator: validator.schema.org

8. Internal Linking

Help search engines discover and understand page relationships.

Internal linking best practices:

1. Link from high-authority pages to new content:

Homepage to key service pages
Popular blog posts to related articles
Main navigation to important pages

2. Use descriptive anchor text:

Poor:

<a href="/services">Click here</a>

Good:

<a href="/services">Web design and development services</a>

3. Create logical site hierarchy:

Homepage
├── Services
│   ├── Web Design
│   ├── Web Development
│   └── SEO Services
├── Blog
│   └── Individual Posts
├── About
└── Contact

4. Every page should be accessible within 3 clicks from homepage:

Keeps important content close to homepage authority
Improves user experience
Helps search engines discover pages faster

5. Fix broken internal links:

Return 404 errors
Hurt user experience
Waste crawl budget

9. Page Titles and Meta Descriptions

These appear in search results and heavily influence clicks.

Title tag best practices:

<title>Primary Keyword - Secondary Keyword | Brand Name</title>

Examples:

Homepage:

<title>Web Design Bristol | Custom Websites for UK Businesses | Build with Simon</title>

Service page:

<title>Next.js Development Services | Fast, Modern Web Apps | Build with Simon</title>

Blog post:

<title>Technical SEO Checklist for New Websites (2025 Guide)</title>

Title tag rules:

50-60 characters (Google truncates longer titles)
Include primary keyword near the beginning
Make it compelling and click-worthy
Unique for every page
Accurately describes page content

Meta description best practices:

<meta name="description" content="Your compelling description here, around 150-160 characters, including your target keyword naturally.">

Meta description rules:

150-160 characters
Include primary keyword
Write for humans (encourage clicks)
Unique for every page
Accurately summarise page content
Include a call-to-action when appropriate

Example:

<meta name="description" content="Complete technical SEO checklist for new websites. Ensure proper indexing, site speed, mobile optimization, and structured data before launch. Free downloadable checklist included.">

10. 404 Error Page

Custom 404 pages keep users engaged when they hit broken links.

Good 404 page includes:

Clear message that page doesn't exist
Search box
Links to popular pages
Link to homepage
Helpful, friendly tone

Example 404 page content:

<h1>Page Not Found</h1>
<p>Sorry, the page you're looking for doesn't exist or has been moved.</p>

<h2>Try these instead:</h2>
<ul>
  <li><a href="/">Go to homepage</a></li>
  <li><a href="/services">View our services</a></li>
  <li><a href="/blog">Read our blog</a></li>
  <li><a href="/contact">Get in touch</a></li>
</ul>

<form action="/search" method="get">
  <input type="text" name="q" placeholder="Search our site">
  <button type="submit">Search</button>
</form>

Technical requirement:

Must return proper 404 HTTP status code
Don't return 200 status (soft 404)
Don't redirect to homepage

11. Redirects

Manage redirects properly to preserve SEO value.

301 Redirect (Permanent):

Use when page moved permanently
Passes 90-99% of link equity
This is what you want for SEO

302 Redirect (Temporary):

Use when page temporarily moved
Doesn't pass full link equity
Rarely needed

Common redirect scenarios:

Old URL structure to new:

yoursite.com/old-page → yoursite.com/new-page (301)

Non-www to www (or vice versa):

yoursite.com → www.yoursite.com (301)

HTTP to HTTPS:

http://yoursite.com → https://yoursite.com (301)

Implementing 301 redirects:

Apache (.htaccess):

Redirect 301 /old-page https://yoursite.com/new-page

Nginx:

rewrite ^/old-page$ /new-page permanent;

Next.js (next.config.js):

module.exports = {
  async redirects() {
    return [
      {
        source: '/old-page',
        destination: '/new-page',
        permanent: true, // 301 redirect
      },
    ]
  },
}

Avoid redirect chains:

Bad:

page-a → page-b → page-c → page-d

Good:

page-a → page-d
page-b → page-d
page-c → page-d

Post-Launch Verification

1. Submit Sitemap to Search Engines

Google Search Console:

Add your property (verify ownership)
Go to Sitemaps section
Submit your sitemap URL
Monitor for errors

Bing Webmaster Tools:

Add and verify your site
Submit sitemap
Check indexing status

2. Monitor Indexing Status

Check indexed pages:

site:yoursite.com

Google this to see how many pages are indexed.

Expected timeline:

Homepage: 1-7 days
Other pages: 1-4 weeks
Full site: 4-8 weeks

If pages aren't indexing:

Check robots.txt isn't blocking
Verify no noindex tags
Ensure sitemap submitted
Check for crawl errors in Search Console
Request indexing via Search Console

3. Check for Crawl Errors

Google Search Console → Coverage report

Common errors:

404 not found: Fix or redirect
Server error (5xx): Fix server issues
Redirect error: Check redirect chains
Blocked by robots.txt: Update robots.txt
Marked noindex: Remove noindex tag

4. Monitor Core Web Vitals

Google Search Console → Core Web Vitals report

Shows performance for mobile and desktop:

Good URLs (green)
URLs needing improvement (yellow)
Poor URLs (red)

Goal: Get all URLs in "Good" category.

5. Test on Multiple Devices and Browsers

Browsers to test:

Chrome (most users)
Safari (iOS users)
Firefox
Edge

Devices to test:

Desktop (various screen sizes)
Mobile (iOS and Android)
Tablet

Test for:

Layout issues
Broken functionality
Slow loading
Missing images
Console errors

Technical SEO Tools

Free tools:

Google Search Console (essential)
Google PageSpeed Insights
Google Mobile-Friendly Test
Google Rich Results Test
Bing Webmaster Tools
Chrome DevTools Lighthouse
Screaming Frog (free up to 500 URLs)

Paid tools (optional but useful):

Ahrefs (£99+/month) - Comprehensive SEO suite
SEMrush (£99+/month) - SEO and marketing platform
Screaming Frog (£149/year) - Unlimited crawling
Sitebulb (£35+/month) - Technical audits

Common Technical SEO Mistakes

1. Launching with noindex tags still active: Check before launch. This is the most common and costly mistake.

2. No SSL certificate: HTTPS is essential. Never launch without it.

3. Ignoring mobile optimization: Google uses mobile-first indexing. Mobile is primary.

4. Slow page speed: Core Web Vitals matter for rankings and user experience.

5. No sitemap or not submitted: Help search engines discover your pages.

6. Broken internal links: Wastes crawl budget and frustrates users.

7. Duplicate content: Use canonical tags to specify preferred versions.

8. Missing or poor title tags/meta descriptions: These are your search result listings. Make them count.

9. Not using structured data: Miss out on rich results and better visibility.

10. Forgetting to verify Search Console: You can't monitor performance without it.

Your Technical SEO Launch Checklist

Print this or save it for launch day:

Pre-Launch:

Launch Day:

Verify site is live and accessible
Remove staging environment noindex
Submit sitemap to Google Search Console
Submit sitemap to Bing Webmaster Tools
Verify Google Search Console property
Request indexing for homepage

Post-Launch (First Week):

Monitor Search Console for errors
Check indexing status (site:yoursite.com)
Verify Core Web Vitals in Search Console
Test all forms and functionality
Monitor server errors (5xx)
Check for 404 errors

Ongoing (Monthly):

Review Search Console coverage report
Monitor Core Web Vitals performance
Check for broken links
Update sitemap as content added
Review page speed metrics
Check mobile usability report

The Bottom Line

Technical SEO is your foundation:

Without it, great content won't rank
Get it right once, benefit forever
Most issues are preventable
Tools make checking easy

Priority order:

Critical: Indexing (robots.txt, noindex, HTTPS, sitemap)
High priority: Speed (Core Web Vitals), mobile optimization
Important: Structured data, internal linking, redirects
Nice to have: Advanced optimizations

Reality check:

Technical SEO isn't glamorous
It won't directly generate content
But it's absolutely essential
Think of it as building a solid house foundation

Timeline:

Setup: 1-2 days for new site
Testing: 1 day thoroughly
Monitoring: Ongoing
Results: Visible within 2-4 weeks

Most technical SEO can be set up correctly from the start, preventing problems rather than fixing them later.

Need Help with Technical SEO?

I build websites with solid technical SEO foundations from day one. Whether you're launching a new site or fixing issues on an existing one, I can audit your technical SEO and implement the fixes needed to help you rank.

Get in touch to discuss your technical SEO needs. Let's make sure search engines can properly crawl, index, and rank your website.