Blog
How-to guides and articles you can reference when the checker finds an issue. Step-by-step for Nginx, Apache, Cloudflare, WordPress, and more.
What Is OCSP Stapling and How to Enable It (Nginx, Apache, Cloudflare)
OCSP stapling lets your server attach a fresh revocation proof to the TLS handshake. Faster, more private, one less round-trip to the CA — and three lines of config in Nginx or Apache.
Read moreHTTP-01 vs DNS-01 vs TLS-ALPN-01: Which ACME Challenge Should You Use?
Let's Encrypt and every modern ACME CA support three validation methods. Wildcards force DNS-01, port-80-closed sites need TLS-ALPN-01, everything else can stick with HTTP-01. A decision guide with certbot examples.
Read moreShort Lived TLS Certificates: What the 47 Day Future Means for Your Site
The CA/Browser Forum approved a phased reduction of TLS certificate lifetimes to 47 days by 2029. What changes for renewals, automation, and monitoring.
Read moreHSTS Preload: How to Submit Your Site and How to Safely Remove It
A practical guide to Strict Transport Security preload: header format, subdomain requirements, how to submit at hstspreload.org, and the slow path to remove a domain.
Read moreALPN vs Alt Svc: Why HTTP/2 and HTTP/3 Detection Tools Disagree
HTTP/2 is negotiated in TLS via ALPN. HTTP/3 is advertised via the Alt Svc header. That is why checkers return different answers, and how to confirm support reliably.
Read moreCertificate Chain Errors: How to Fix an Incomplete SSL Chain
Missing intermediate certificates cause ERR_CERT_AUTHORITY_INVALID. Fix fullchain.pem, Nginx/Apache config, and verify with openssl or our SSL checker.
Read moreWhat Is a CAA Record and Why Does It Matter for SSL?
CAA DNS records restrict which certificate authorities can issue TLS certs for your domain. Tags, examples, and how our checker surfaces CAA.
Read more301 vs 302 vs 307 Redirects: Which Status Code Should You Use?
Permanent vs temporary redirects, SEO, caching, and when to use 301, 302, 307, or 308—including HTTP→HTTPS. Verify chains with our redirect checker.
Read moreBulk SSL Checker: How to Check Multiple Domains at Once
Check SSL and HTTPS for up to 10 domains in one go. Get grades, redirect chains, and certificates. Export to PDF or JSON, share report links. No signup.
Read moreHTTP/2 and HTTP/3: What They Are and How to Enable Them
HTTP/2 and HTTP/3 speed up your site with multiplexing and QUIC. Here's what they do and how to turn them on in Nginx and Cloudflare.
Read moreWhat Is Mixed Content and How to Fix It
Your page is HTTPS but some images, scripts or styles still load over HTTP. Browsers block them or warn. Here's how to find and fix mixed content on your site.
Read moreWhy HTTPS Matters for SEO (And How to Check Yours)
Google uses HTTPS as a ranking signal and prefers secure pages. Here's why it matters for SEO and how to see if your site is set up right.
Read moreSecurity Headers: What They Are and How to Set Them
Guide to HTTP security headers: HSTS, Content-Security-Policy, X-Frame-Options, and more. How to add them in Nginx, Apache, and Cloudflare.
Read moreHow to Fix a Redirect Loop
Step-by-step guide to fix redirect loops (ERR_TOO_MANY_REDIRECTS): trace the loop, fix conflicting rules in Nginx, Apache, Cloudflare.
Read moreHow to Fix SSL Certificate Errors
Step-by-step guide to fix SSL certificate errors: renewal (Let's Encrypt, certbot), certificate chain, Nginx, Apache, cPanel, Cloudflare.
Read moreHow to Fix HTTP to HTTPS Redirect
Step-by-step guide to set up a 301 redirect from HTTP to HTTPS on Nginx, Apache, Cloudflare, and WordPress.
Read moreHow to Install Nginx, Certbot, and SSL on Ubuntu 24
Step-by-step guide: install Nginx and Certbot on Ubuntu 24, configure a domain with Let's Encrypt SSL, and set up HTTPS redirect.
Read more
Get security tips & updates
Occasional emails on HTTPS, SSL, and security headers. No spam, unsubscribe anytime.