Technical SEO Audits with Free Tools: How to Do a Deep Audit on a Budget

You don’t need an expensive subscription to run a professional-grade SEO audit.

While paid tools like Ahrefs, Semrush, and DeepCrawl offer advanced features, there’s a powerful set of free tools that can help you uncover hidden technical issues, boost site speed, and improve your organic visibility — all without breaking the bank.

In this guide, we’ll walk through how to perform a full technical SEO audit using only free tools, step by step.

1. Why a Technical SEO Audit Matters

Technical SEO is the foundation of your website’s visibility. Even the best-written content won’t rank if your site is hard to crawl, loads slowly, or has broken links.

A regular audit helps you:

• Detect crawl and indexation errors
• Improve loading times and Core Web Vitals
• Ensure proper site structure and internal linking
• Fix duplicate content and broken redirects
• Enhance user experience across devices

When done consistently, audits reveal small issues before they snowball into ranking drops.

2. The Essential Free Tools for a Technical SEO Audit

Here are the top free tools you’ll use throughout your audit:

Each tool offers unique insights — combining them gives you a 360° view of your site health.

3. Step-by-Step: How to Perform a Free Technical SEO Audit

Step 1: Crawl Your Site

Use Screaming Frog or Ahrefs Webmaster Tools to crawl your site.

Look for:

• Broken internal/external links (404 errors)
• Redirect chains and loops
• Missing title tags or meta descriptions
• Duplicate pages
• Incorrect canonical tags

Tip: Export the crawl data into a spreadsheet — this becomes your fix list.

Step 2: Check Crawlability and Indexation

Open Google Search Console → Indexing → Pages.

Look for pages marked as:

• “Crawled – currently not indexed”
• “Discovered – currently not indexed”
• “Blocked by robots.txt”

Ensure your sitemap is correctly submitted under Sitemaps and all key pages are indexable.

Step 3: Evaluate Site Speed and Core Web Vitals

Use PageSpeed Insights and Lighthouse to analyze desktop and mobile performance.

Focus on improving:

• Largest Contentful Paint (LCP)
• First Input Delay (FID)
• Cumulative Layout Shift (CLS)

Pro Tip: Compress images (via TinyPNG or Squoosh), leverage browser caching, and use a lightweight theme.

Step 4: Inspect Mobile Friendliness

Mobile-first indexing means Google uses your mobile version for ranking.

Use the Mobile-Friendly Test (built into PageSpeed Insights) to confirm:

• Responsive design
• Proper viewport scaling
• No overlapping elements or text too small to read

Step 5: Audit Structured Data and Schema Markup

Go to Google’s Rich Results Test or Schema.org Validator to verify that your structured data (FAQ, Product, Article, LocalBusiness, etc.) is valid.

Why it matters: Schema helps your site qualify for rich results — which improve CTRs dramatically.

Step 6: Review Security and HTTPS

Ensure your SSL certificate is valid, and your site uses HTTPS across all URLs.

Check for mixed content errors (HTTP assets on HTTPS pages) using Screaming Frog’s “Protocol” filter.

Step 7: Inspect Internal Linking & Site Structure

Free tools like Visual Site Mapper or GSC’s Links Report help visualize your internal link network.

Key checks:

• Important pages should be ≤3 clicks from the homepage
• Avoid orphan pages
• Use descriptive anchor text

Pro Tip: Strengthen internal links between related posts to boost topic authority.

4. Bonus: Automate Ongoing Monitoring

You don’t have to manually recheck everything every month.

Set up free automated alerts in Google Search Console for:

• Coverage issues
• Page experience changes
• Security warnings

Re-run a mini audit quarterly to catch new technical issues before they affect rankings.

5. Free SEO Audit Checklist (Summary)

6. When to Consider Paid Tools

Once you’re auditing sites with thousands of pages or managing multiple clients, upgrading to paid platforms like Ahrefs, Semrush, or Sitebulb saves time and reveals deeper crawl insights.

But until then — free tools can take you a long way.

Conclusion

You don’t need a hefty SEO budget to stay ahead of competitors.

By mastering the free tools available, you can uncover critical issues, fine-tune your site’s performance, and set a strong foundation for long-term SEO success.

At The Ocean Marketing, we specialize in helping brands build sustainable SEO strategies that grow traffic — not just rankings.

Need help auditing or optimizing your website? Contact us for a free consultation today.