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A technical SEO checklist

Status codes, canonicals, robots rules, HTTPS, speed and mobile: what to check and why.

Lesson
5/7
Reading time
9 min
Sections
5
Through the course
71%

Status codes

  • 200: page served. 301: moved permanently (passes signals to the new URL). 302: temporary.
  • 404/410: gone. Fine for genuinely removed pages, but fix internal links that point to them.
  • 5xx: server errors. Repeated errors make crawlers back off and can drop pages from the index.

Canonicals and duplicates

When the same content is reachable at several URLs (tracking parameters, http and https, trailing slashes), a canonical link tells engines which one to index. Each page should have a single canonical, normally pointing to itself.

Robots rules

robots.txt controls crawling; the robots meta tag and X-Robots-Tag header control indexing. Blocking a page in robots.txt does not remove it from the index; use noindex for that, and let it be crawled so the tag can be seen.

HTTPS and security headers

Serve every page over HTTPS, avoid loading resources over plain HTTP, and send a Strict-Transport-Security header so browsers always use the secure version.

Step by step

  1. 1Check status codesFix 5xx errors before anything else, then internal links to 404s; use 301 for permanent moves.
  2. 2Check canonicalsOne canonical per page, normally pointing to itself.
  3. 3Check robots rulesMake sure important pages aren't blocked or set to noindex by accident.
  4. 4Check HTTPSEvery page and resource on HTTPS, with a Strict-Transport-Security header.
  5. 5Check speed and mobileDevice-width viewport without disabling zoom, and good page experience from real visitors.

Speed and mobile

  • Fast server response and compressed, cacheable HTML.
  • A viewport tag using device-width that doesn't disable zoom.
  • Page experience from real visitors: largest contentful paint, interaction to next paint and layout shift.

Lesson 5 of 7

A technical SEO checklist