The SEO Agency Technical Checklist: What a Real Site Audit Should Cover

You’ve hired an SEO agency, or you’re about to. The pitch deck looked great—lots of colorful charts, promises of “growth,” and a slide about “technical health.” But when you ask for the actual audit methodology, the conversation gets vague. That’s a red flag. A serious technical SEO audit isn’t a one-page PDF with a traffic projection. It’s a forensic examination of how search engines see your site, what they can and cannot access, and where your server, code, or structure is leaking authority.

This article is a checklist. Use it to brief your agency, evaluate their deliverables, or run your own first-pass technical review. We’ll cover the five core pillars: crawlability and indexation, site architecture and duplicate content, Core Web Vitals and performance, on-page optimization and keyword intent, and link profile risk. Each section ends with a concrete step list. No fluff, no guaranteed rankings.

1. Crawl Budget and Indexation: Are You Wasting Google’s Time?

Before any content strategy matters, Googlebot has to find your pages. This sounds obvious, but I’ve seen sites with 50,000 indexed URLs where 45,000 are parameterized search results, tag pages, or thin affiliate content. That’s a crawl budget disaster. Your agency should start by analyzing how Googlebot spends its time on your domain.

The first document to review is your robots.txt. Is it blocking critical resources like CSS, JS, or images? Is it accidentally disallowing an entire section you want indexed? The second is your XML sitemap. This isn’t a “set it and forget it” file. It should contain only canonical, indexable, high-value URLs. No pagination parameters, no session IDs, no staging URLs. If your sitemap includes 10,000 URLs but your site has 200,000 pages, you’re signaling to Google that most of your content is low priority.

A proper audit will also check crawl rate settings in Google Search Console. If your server is slow, Google throttles itself. If your site is massive and fast, you might want to increase the rate. The agency should provide a crawl budget report showing:

• Number of crawled pages vs. discovered pages
• Crawl frequency trends over 30 days
• Blocked resources (robots.txt or noindex directives)
• Sitemap submission errors

Step-by-Step Crawl Budget Check

1. Export your current sitemap and cross-reference it with your actual URL inventory.
2. Run a crawl with a tool like Screaming Frog or Sitebulb, set to “Googlebot” user-agent.
3. Identify pages returning 3xx, 4xx, or 5xx status codes.
4. Check robots.txt for accidental blocks on CSS, JS, or image files.
5. Review Google Search Console’s “Crawl Stats” report for anomalies.

2. Duplicate Content and Canonicalization: The Silent Leak

Duplicate content isn’t a penalty in the algorithmic sense, but it forces Google to choose which version to rank. If you have three URLs serving the same product description, you’re splitting link equity and confusing the index. The solution is canonical tags—but only if they’re implemented correctly.

I’ve audited sites where every page had a self-referencing canonical tag pointing to the homepage. That’s a catastrophic error. I’ve also seen sites with no canonical tags at all, relying on 301 redirects that should have been 302s. Your agency needs to map out every URL pattern and decide the canonical for each.

Common problem areas include:

• HTTP vs. HTTPS versions
• www vs. non-www
• Trailing slash vs. non-trailing slash
• URL parameters (sort, filter, page)
• Session IDs in URLs
• Printer-friendly versions

A table like the one below should be part of your audit deliverable.

Step-by-Step Canonical Check

1. Crawl your entire site and export all canonical tags.
2. Look for canonical tags pointing to different domains or 4xx pages.
3. Check for missing canonicals on paginated or faceted navigation pages.
4. Verify that all HTTPS pages have a self-referencing canonical or redirect to the correct HTTPS version.

3. Core Web Vitals and Site Performance: The User Experience Tax

Since the Page Experience update, Core Web Vitals are a ranking factor. But more importantly, slow sites lose conversions. Your agency should not just run a Lighthouse report and call it done. They need to dig into real-user monitoring (RUM) data from Chrome User Experience Report (CrUX) and correlate it with your analytics.

The three metrics—LCP (Largest Contentful Paint), FID/INP (First Input Delay / Interaction to Next Paint), and CLS (Cumulative Layout Shift)—each have different root causes. LCP is often a server response time or render-blocking resource issue. CLS is usually missing width/height attributes on images or dynamic ad injections. INP is about JavaScript execution and event handlers.

A thorough audit will provide:

• CrUX data for your domain (origin-level and URL-level)
• Lab data from Lighthouse or WebPageTest
• Recommendations prioritized by impact (server-side vs. client-side)
• A baseline and target for each metric

If your agency only shows you a Lighthouse score of 85 and says “good enough,” push back. Lighthouse is a lab test on a clean connection. Real-world performance varies by device, network, and location. They should segment your traffic by mobile vs. desktop, 3G vs. 4G, and geographic region.

For deeper performance optimization, see our guides on site speed optimization and LCP optimization.

Step-by-Step Core Web Vitals Check

1. Pull your CrUX data from Google Search Console or BigQuery.
2. Identify the worst-performing URLs by metric.
3. Run WebPageTest on those URLs with mobile throttling.
4. Check for render-blocking resources, large images, and third-party scripts.
5. Create a performance budget (max LCP 2.5s, CLS 0.1, INP 200ms).

4. On-Page Optimization and Keyword Intent: Beyond Title Tags

On-page SEO is not just stuffing keywords into title tags and H1s. That’s a 2010 tactic. Modern on-page optimization starts with intent mapping. Your agency should classify every target keyword into one of four intents: informational, navigational, commercial, or transactional. Then, they should map that intent to a content format and page type.

For example, a keyword like “best running shoes for flat feet” has commercial intent. The page should be a comparison or listicle, not a product page. A keyword like “how to tie running shoes” is informational—it belongs on a blog or guide page. If your agency is targeting both with the same page structure, they’re missing the point.

The audit should also check:

• Title tags (length, uniqueness, keyword placement)
• Meta descriptions (compelling, includes CTA)
• Header structure (H1 to H3 hierarchy)
• Internal linking (anchor text, relevance, depth)
• Image optimization (alt text, file names, compression)

For image-specific issues, read our articles on image optimization for SEO and image alt text best practices.

Step-by-Step On-Page Check

1. Export your top 100 ranking pages and their target keywords.
2. Check if the page’s content matches the search intent of the keyword.
3. Review title tags for length (50-60 chars) and uniqueness.
4. Verify that every image has an alt attribute (even if empty for decorative images).
5. Map internal links from high-authority pages to thin content pages.

5. Link Building and Backlink Profile: Quality Over Quantity

Link building is the riskiest part of SEO because you don’t control the other site. A bad backlink profile can trigger manual actions or algorithmic penalties. Your agency should start with a backlink audit before proposing any outreach. They need to analyze your current link profile for toxic signals: spammy domains, exact-match anchor text overuse, low Trust Flow to high Citation Flow ratio, and links from link farms or PBNs.

If your agency suggests buying links from a “private blog network” or using automated tools for outreach, run. Those tactics work until they don’t, and recovery takes months. Legitimate link building is about earning links through content, relationships, or digital PR. Your agency should provide a strategy that includes:

• Competitor backlink gap analysis
• Content assets designed to attract links (data studies, original research, tools)
• Outreach templates that are personalized and value-driven
• A risk assessment for any paid or guest post campaigns

The table below compares common link building approaches by risk and sustainability.

Step-by-Step Link Profile Check

1. Export your backlink profile from Ahrefs, Majestic, or SEMrush.
2. Filter by domain rating or trust flow below 10.
3. Check for exact-match anchor text over 5% of total links.
4. Review the linking domains for spam signals (thin content, no traffic, unrelated niche).
5. Disavow any links that are clearly manipulative or from penalized domains.

For more on structured data, see our guide on image schema markup.

Final Checklist Summary

Before you sign off on an agency’s technical audit, use this checklist to verify completeness.

• Crawl budget analysis (robots.txt, sitemap, crawl stats)
• Duplicate content and canonical tag audit
• Core Web Vitals baseline (CrUX data, lab tests, prioritized fixes)
• On-page optimization (intent mapping, title tags, headers, internal links)
• Backlink profile risk assessment and disavow plan
• Image optimization (alt text, compression, file names)
• Performance budget and monitoring plan

A good agency will deliver all of this in a structured report with clear next steps. If they hand you a three-page PDF with generic advice, you’re not getting technical SEO. You’re getting a brochure. Demand the checklist.