What's the first technical SEO error you check on the new site?

Elowyn said:

Hi,
I am working on new website and need to know what are the important technical error should be optimized.
So, i want to listen from you that what kind of technical errors you check on your website? Waiting for your replies.

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I usually start with crawl errors, broken links (404), redirect chains, duplicate content, missing meta tags, XML sitemap and mobile usability. Fixing these early makes future SEO much easier.

The first thing i check is whether the important pages are actually being indexed. Then i review the robits.txt file, XML sitemap and make sure there are not any accidental noindex tags. I have seen new websites lose weeks of potential traffic just because of a simple indexing issue.

Elowyn said:

Hi,
I am working on new website and need to know what are the important technical error should be optimized.
So, i want to listen from you that what kind of technical errors you check on your website? Waiting for your replies.

Click to expand...

The first thing I check is whether Google can actually crawl and index the site robots.txt, no index tags, canonical tags, and XML sitemaps. If those are correct, I move on to crawl errors, internal linking, Core Web Vitals, and duplicate content.

One of the first things I check is whether search engines can actually crawl and index the important pages. After that, I usually look for broken links, redirect chains, duplicate title tags and meta descriptions, canonical issues, XML sitemap, robots.txt, Core Web Vitals, and mobile usability. I also make sure there are no orphan pages because they're easy to overlook. In my opinion, fixing these basics early makes everything else much easier later on.

The basics i always check first are crawlability, indexability, page speed, mobile usability, broken links, redirect chains, duplicate content, and proper canonicals. After that, i look at structured data, xml sitemaps, robots.txt, and core web vitals. Fixing those usually covers the most important technical seo issues.

Most of the basics are covered here but one thing i always see people mess up on new builds is staging environments. Double check that your dev or staging subdomain isnt indexable... devs love to leave those wide open and google will find and index them before you even launch. Also @SyedHabib-SEOExpert mentioned canonicals, but watch out for server response times (TTFB) under load. If your hosting chokes when a crawler hits it, your crawl budget goes out the window anyway.

Elowyn said:

Hi,
I am working on new website and need to know what are the important technical error should be optimized.
So, i want to listen from you that what kind of technical errors you check on your website? Waiting for your replies.

Click to expand...

The first thing I check on a new site that "should be ranking but isn't" isn't robots.txt, it's the HTTP headers. curl -I https://site.com takes five seconds.

I've found three sites this year where a dev set X-Robots-Tag: noindex on staging, the site went live, nobody removed that one line in .htaccess or nginx, and Google silently obeyed it for weeks — sometimes months. The site loaded fine for humans. Sitemaps submitted. Pages looked perfect in a browser. Zero traffic. The problem lived in a header you can't see unless you know to look for it.

Here's the part that makes me twitchy: sometimes curl -I lies to you. If you're behind Cloudflare or any CDN that injects headers, the noindex might only appear for Googlebot's user-agent. I watched someone chase this for three days — GSC reported noindex, every curl check came back clean, Screaming Frog said everything was fine. The CDN had a rule that only fired X-Robots-Tag when the visitor looked like Google. You need curl -I -H "User-Agent: Googlebot" to catch it.

And if you're on Next.js or React: check your shared layout components. I've seen a single <meta name="robots" content="noindex"> in a layout file meant for staging propagate to every page in production. Nobody noticed because they were spot-checking individual route files, not the shared wrapper. One component. Entire site invisible.

Quick bonus: don't trust site:yourdomain.com as a health check. It's notoriously incomplete and hides orphans. And a sitemap submission isn't the same as internal links — Google treats sitemap-only pages as second-class citizens if nothing internal points to them.

If you do nothing else: curl -I with the Googlebot UA, then check your layout components. That's thirty seconds that's saved me more time than any audit tool.

Elowyn said:

Hi,
I am working on new website and need to know what are the important technical error should be optimized.
So, i want to listen from you that what kind of technical errors you check on your website? Waiting for your replies.

Click to expand...

Broken link redirect chains and incorrect canonicals are my first technical checks.