What is DMARC?
Learn what DMARC is, how it builds on SPF and DKIM to stop others spoofing your domain, and how to publish a first monitoring record safely.
Quick answers guides
Practical, step-by-step website launch and SEO health guides.
Categories: Quick answers (100)
Showing 73 to 96 of 100 guides in Quick answers (page 4 of 5)
What is duplicate content and does Google penalize it?
Learn what counts as duplicate content, why Google usually does not penalize it, and how to reduce duplicates with redirects, canonicals and unique text.
What is FAQ schema and does it still show in Google?
FAQ schema marks up questions and answers with FAQPage structured data. See what changed in Google Search, what it still does, and whether to keep it.
What is field data in Core Web Vitals (CrUX)?
Field data is performance measured on real visitors' devices and collected in the Chrome User Experience Report. See where to find it and its limits.
What is hreflang?
Hreflang tells Google which language or regional version of a page to show to which searchers. Learn the format, the rules and the common mistakes to avoid.
What is HSTS?
HSTS is a response header that tells browsers to use only HTTPS for your site. See an example, safe starting values and the preload risks to avoid.
What is INP in Core Web Vitals?
Interaction to Next Paint measures how quickly a page reacts to taps, clicks and key presses. Learn the 200 ms target and how to find slow interactions.
What is JSON-LD?
JSON-LD is the format Google recommends for structured data. See what it is, how a small block looks, where it goes on a page and how to test it.
What is lazy loading and when should I use it?
Lazy loading delays images and frames until they are close to view. See when it helps, when it hurts your main image and how to add it correctly.
What is LCP in Core Web Vitals?
Largest Contentful Paint times how long the main content takes to appear. See the 2.5 second target, what element counts and where to measure it.
What is mixed content and how do I fix it?
Mixed content happens when an HTTPS page loads images, scripts or styles over HTTP. See why browsers block it and how to find and fix every case.
What is MTA-STS?
Learn what MTA-STS is, how a DNS record and a policy file make other mail servers use encrypted TLS when sending to you, and how to roll it out safely.
What is Organization schema?
Organization schema tells search engines your business name, website, logo and official profiles. See the key properties, an example and where to put it.
What is reverse DNS (PTR) and why does email need it?
Learn what a reverse DNS PTR record is, why mail servers check it on the sending IP, and how to test and request one for your own mail server.
What is robots.txt?
robots.txt is a small text file that tells crawlers which parts of a site they may visit. See what goes in it, a working example and common pitfalls.
What is the best JSON-LD testing tool?
Compare Google's Rich Results Test with the Schema Markup Validator, see which to run first, and learn how to read errors and warnings in your JSON-LD.
What is the sitemap size limit?
A sitemap file may hold 50,000 URLs and 50 MB uncompressed. See how to count yours and what to do when a site grows past either limit.
What is the sp= tag in DMARC?
Learn how the DMARC sp= tag sets a separate policy for subdomains, when it is inherited from p=, and how to protect domains that never send mail.
What is the viewport meta tag?
The viewport meta tag tells phones how wide to make your page. See the standard tag, what each part means and why you should not block pinch zoom.
What is TLS-RPT?
Understand TLS-RPT, the DNS record that asks other mail servers to report TLS delivery failures to you, and how it works alongside MTA-STS.
What is TTFB and what is a good value?
Time to First Byte is how long a browser waits for the first piece of a response. See the 0.8 second target, what slows it down and how to measure it.
What replaced FID in Core Web Vitals?
Interaction to Next Paint took over from First Input Delay in March 2024. See what changed, why Google switched and what to measure on your site now.
Where is my sitemap.xml?
Find the address of your sitemap.xml with five quick checks: the default path, robots.txt, Search Console, common plugin names and your CMS settings.
Why are my images not loading (broken images)?
Find out why website images show as broken: wrong paths, deleted files, blocked requests and mixed content. Follow a quick check to find and fix the cause.