Cache-Control header missing — the fix
Static resources on this page are served without a Cache-Control HTTP header. Without caching directives, browsers may re-download resources on every visit.
Where this fits: performance in SEO
Performance is both a ranking signal (Core Web Vitals) and a conversion multiplier. Google measures real-user loading (LCP), interactivity (INP), and visual stability (CLS) — and slow sites lose visitors before analytics even registers them. Most performance issues concentrate in a few repeat offenders: unoptimised images, render-blocking resources, and third-party scripts. Fixing the top three usually moves the needle more than fixing the next thirty.
Why cache-control header missing hurts your rankings
Proper caching prevents browsers from re-downloading unchanged resources, dramatically improving repeat visit performance. Without Cache-Control headers, browsers use heuristic caching which is unpredictable. Google PageSpeed Insights specifically checks for efficient cache policies on static resources.
This is a medium-severity issue: individually modest, but it compounds — dozens of medium issues across hundreds of pages add up to a real quality deficit in how search engines assess the site.
How to fix it
Add Cache-Control headers to all static resources (CSS, JS, images, fonts). Use long max-age values (at least 1 year) for versioned assets with cache-busting filenames. Use shorter durations for HTML and API responses.
# Nginx: cache static assets for 1 year
location ~* \.(css|js|jpg|jpeg|png|gif|ico|svg|woff2)$ {
add_header Cache-Control "public, max-age=31536000, immutable";
}Performance best practices
- Serve images in modern formats (WebP/AVIF), sized to their container, with explicit dimensions.
- Inline critical CSS and defer everything else; eliminate render-blocking third parties.
- Set far-future cache headers on static assets and an ETag on everything.
- Preload the fonts and hero image; font-display: swap to avoid invisible text.
- Measure with real-user Core Web Vitals, not just lab scores — Google ranks on field data.
The full library: SEO best practices, by category.
Frequently asked questions
What does "Cache-Control header missing" mean?
Static resources on this page are served without a Cache-Control HTTP header. Without caching directives, browsers may re-download resources on every visit.
Why does cache-control header missing matter for SEO?
Proper caching prevents browsers from re-downloading unchanged resources, dramatically improving repeat visit performance. Without Cache-Control headers, browsers use heuristic caching which is unpredictable. Google PageSpeed Insights specifically checks for efficient cache policies on static resources.
How do I fix cache-control header missing?
Add Cache-Control headers to all static resources (CSS, JS, images, fonts). Use long max-age values (at least 1 year) for versioned assets with cache-busting filenames. Use shorter durations for HTML and API responses.
How serious is this issue?
This is a medium-severity issue: individually modest, but it compounds — dozens of medium issues across hundreds of pages add up to a real quality deficit in how search engines assess the site. It belongs to the performance family of checks.
How do I find every page affected by this on my site?
Run a free Dr Urls audit: it crawls your site, detects cache-control header missing on every affected page, shows example URLs, and generates a ready-to-use fix task. Re-scan after fixing to verify the issue is gone.
Does your site have this issue?
A free Dr Urls audit crawls your site, finds every page affected by cache-control header missing, and hands you a ready-made fix task.
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