HTTPS: what it is and why it matters

What is HTTPS?

HTTPS is the combination of HTTP and Transport Layer Security (TLS). It provides encryption (confidentiality), integrity checks, and server authentication so that data exchanged between a browser (or other client) and a web server is protected from interception and tampering. In practice a site that uses HTTPS serves HTTP traffic over a TLS-secured socket and presents a certificate issued by a trusted Certificate Authority (CA).

Why HTTPS matters for SEO

HTTPS is now a baseline expectation for both users and browsers. For SEO, the practical effects include improved user trust and fewer browser security warnings, preserved referral data on secure→secure transitions, and compatibility with features that require secure contexts (for example, many modern web APIs and progressive web app functionality). Historically Google has used HTTPS as a lightweight ranking signal; more importantly, a broken or misconfigured HTTPS deployment can cause crawl failures or indexation issues that indirectly hurt visibility. Remember: crawling, indexing and ranking are separate stages — HTTPS affects how pages are fetched and considered for indexing, but ranking decisions combine many signals beyond transport security.

How HTTPS works

At a high level HTTPS uses TLS to establish a secure channel before HTTP payloads are exchanged. Typical steps in the TLS handshake are: the client sends a ClientHello, the server responds with its certificate and chosen parameters, the client validates the certificate chain and negotiates keys, and both sides derive symmetric keys used for the session. Modern deployments use TLS 1.3 where supported; older TLS versions are progressively deprecated. Additional pieces to be aware of include the certificate chain (leaf, intermediate, root), OCSP/OCSP stapling for revocation checks, and support for HTTP/2 or HTTP/3 which run over TLS and can improve performance when configured correctly.

Types of HTTPS certificates

Common certificate types and their tradeoffs:

• Domain-validated (DV) — issued after proving control of a domain. Pros: fast and generally free (e.g., Let's Encrypt); cons: provides only domain-level identity.
• Organization-validated (OV) — adds company identity checks; Pros: shows organization info in certificate metadata; cons: higher cost and issuance time.
• Extended Validation (EV) — historically stricter checks and distinct UI in some clients; Pros: stronger identity checks; cons: many browsers no longer surface special UI for EV.
• Wildcard and SAN (multi-domain) certificates — cover multiple subdomains or hostnames; Pros: simpler management for many hostnames; cons: wildcard keys increase blast radius if private key is exposed.
• Self-signed — not trusted by browsers and unsuitable for public sites.

How to get started with HTTPS

Core steps to implement HTTPS for a public website:

1) Obtain a certificate from a trusted CA (including free CAs such as Let's Encrypt) or from your hosting/CDN provider. 2) Install the certificate and related intermediate chain on your origin or edge servers. 3) Configure secure TLS settings (prefer modern versions and strong cipher suites) and enable OCSP stapling. 4) Implement server-side 301 redirects from HTTP to HTTPS and ensure canonical tags point to the preferred HTTPS URL. 5) Update internal links, sitemaps, hreflang entries and any hard-coded references. 6) Test for mixed content and fix insecure asset URLs. 7) Optionally enable HSTS after testing (carefully consider the preload option).

Common HTTPS mistakes

Watch for these frequent errors that affect both UX and search visibility:

• Missing or broken redirect chains — some pages remain accessible over HTTP while canonical and sitemap entries point to HTTPS.
• Mixed content — pages served over HTTPS include subresources loaded over HTTP, which browsers block or warn about.
• Expired or incomplete certificate chain — browsers or crawlers may refuse the connection.
• HSTS misconfiguration — enabling preload before validating every variant (www, non-www, IPv6) can cause lock-in.
• Blocking crawlers at TLS level — strict firewall/TLS policies that block Googlebot or other search crawlers can prevent indexing.
• Forgetting third-party services — update CDN, analytics, tag managers and API endpoints to use HTTPS.

HTTPS checking: technical checklist

**Certificate validity** — where to verify: browser padlock > certificate details, SSL Labs or openssl — passes when certificate is issued by a trusted CA, chain is complete, and dates are valid.

**Redirects to HTTPS** — where to verify: curl -I -L https://example.com (replace with your host) — passes when HTTP requests return 301/308 redirects that end at the canonical HTTPS URL.

**Mixed content** — where to verify: browser DevTools Console or automated scanner — passes when no active mixed content (scripts, iframes) is blocked and all critical assets are loaded over HTTPS.

**TLS protocol and cipher support** — where to verify: SSL Labs or openssl s_client -connect example.com:443 -servername example.com — passes when modern TLS versions (TLS 1.2/1.3) are enabled and insecure ciphers are disabled.

**HSTS header** — where to verify: curl -I https://example.com — passes when Strict-Transport-Security header is present with intended directives (test before preloading).

**Search engine access** — where to verify: server logs and Google Search Console (for sites you own) — passes when Googlebot and other major crawlers can fetch HTTPS responses without TLS errors.

Practical commands and tools

Useful checks you can run from your workstation or CI pipeline:

• View headers and redirects: curl -I -L https://example.com (use -I to fetch headers only; -L follows redirects).
• Inspect TLS certificate chain: openssl s_client -connect example.com:443 -servername example.com (check the certificate details shown).
• Quick browser check: open the page, click the padlock and view certificate information.
• Automated grading: run SSL Labs (Qualys SSL Labs) or your CI TLS scanner to get a report on protocol support, cipher suites and chain issues.
• For owned properties: use Google Search Console URL Inspection to confirm Google can fetch and index the HTTPS page; remember URL Inspection is authoritative only for sites you own.

Note on crawlers: Google crawls sites with Googlebot Smartphone by default; ensure your TLS stack, SNI and firewall rules allow access by major crawler user-agents so that crawling and indexing are not interrupted.

Read the Technical SEO Guide

Frequently asked questions