How to Use HTTPS and Varnish in Magento 2 Setups?

• What is HTTPS?

• How Does HTTPS Boost Ranking?

• What is Varnish Cache?

• How Varnish Cache Acts as a Web Accelerator?

• What is ESI?

• How does ESI Work?

• Does Core Web Vitals affect HTTPS and Varnish in 2025?

• How HTTPS and Varnish Boost Search Engine Standing?

• How to Manage Conflicts Faced with Varnish and HTTPS on Websites?

• Tips to Improve Your Magento 2 Store Search Engine Ranking

• FAQs

• Summary

What is HTTPS?

“HTTPS stands for Hypertext Transfer Protocol Secure, used for secure web communication. It is the secure version of the standard HTTP protocol.”

HTTPS encrypts data exchanged between a user's browser and a website. This encryption protects sensitive information from unauthorized third-party interception. Transport Layer Security (TLS) or Secure Sockets Layer (SSL) provides this encryption.

HTTPS offers several critical security features for all websites:

• Encryption scrambles data, making it unreadable to outside attackers.

• Data integrity confirms information remains unchanged during its transit.

• Authentication verifies the website's identity, building strong user trust.

Web browsers display a padlock icon for HTTPS-secured web connections. The visual cue signals a safe browsing environment to users. Search engines favor HTTPS sites, recognizing their enhanced user protection. HTTPS is essential for modern website security and user confidence.

How Does HTTPS Boost Ranking?

“HTTPS boosts website search engine ranking signals. Google reports that 93% of the top million sites run on HTTPS in 2025. 88% of all web traffic also runs on HTTPS. It pushes hosts worldwide to adopt secure delivery.”

Key HTTPS benefits that search engines value for ranking include:

• Encryption to protect sensitive user data during online transmission.

• Data integrity to prevent file corruption during website data transfer processes.

• Authentication to confirm website identity, preventing phishing attack methods.

• Increased user trust, leading to lower website bounce rates.

• Secure sites to meet user expectations for online safety requirements today.

Switching to HTTPS shows a commitment to user safety standards. Search engines reward this commitment with improved website visibility. Modern HTTPS implementations use advanced TLS 1.3 and HTTP/3 protocols. These protocols offer stronger encryption and faster handshake processes.

What is Varnish Cache?

“Varnish Cache acts as a caching HTTP reverse proxy. It sits before your web server infrastructure and stores copies of web pages in memory.”

The cache speeds content delivery to users, reducing server load and response times. It can handle (300-1000x) requests per second.

Key Varnish cache features include:

• Delivers content fast from memory for users.

• Offers flexible caching using Varnish Configuration Language.

• Supports load balancing across multiple backend servers.

• Provides Edge Side Includes for partial page caching.

• Works with web servers like Apache or Nginx.

Many high-traffic websites use Varnish for speed. The community releases "fresh" versions twice a year. The current Varnish Cache "fresh" release, version 7.7.0, came out in March 2025. Varnish Cache 6.0 LTS remains a stable version.

How Varnish Cache Acts as a Web Accelerator?

“Varnish Cache accelerates web delivery via strategic in-memory object storage. It intercepts HTTP requests before slower origin servers receive them.”

Key granular acceleration techniques Varnish employs for sites include:

• RAM storage bypasses backend disk I/O operations for speed. Varnish avoids slow, blocking disk read and write operations.

• VCL in vcl_recv manipulates incoming request header data fields. It allows early routing or request user modification processes.

• vcl_hash customization guarantees precise object cache lookup result generation. It creates unique keys for cached response storage data.

• Edge Side Includes (ESI) enables a dynamic fragment caching system with advantages. ESI assembles pages from cached and uncached components.

• Request coalescing merges identical concurrent requests into one backend hit. The method reduces the redundant work volume on the origin server.

Varnish uses fast RAM, not disk, for storing responses. The system cuts retrieval latency for accessed web content. Varnish Configuration Language (VCL) provides fine-grained control over request processing. VCL customizes caching logic within its specific finite state machine.

The provided information about ESI has potential for improvement. Here is a revised version adhering to the specified constraints.

What is ESI?

“ESI, or Edge Side Includes, is a markup language. It assembles dynamic web content at the network edge.”

ESI tackles web infrastructure scaling for better site performance. ESI applies edge computing, improving total website load speed.

Varnish caches dynamic website content with effective ESI use. It caches static parts of a dynamic web page, which helps the HTTP accelerator. Faster dynamic content loading increases ESI's core importance value.

Key ESI features:

Inclusion: ESI assembles content fragments, creating complete web page structures.

<esi:include src="http://example.com/1.html" alt="http://backup.example.com/2.html" onerror="continue"/>

Inclusion allows caching of page assets and individual content fragments.

Variables: ESI allows variable insertion into the web markup. ESI defines these variables using HTTP header cookie data.

Conditions: ESI uses conditional logic for different markup block presentations. The feature enables content display based on a specified set of criteria.

Error Handling: ESI specifies alternative URLs for unavailable origin server site resources. It confirms content delivery with certain origin server issues.

How does ESI Work?

ESI assembles dynamic web content for many web applications. It solves scaling problems within the e-commerce site's infrastructure.

For example, a webshop page displays user-specific site information in the cart.

• An empty cart shows a "Cart (0)" specific label.

• An item addition changes the label text to "Cart (1)".

• The remaining page content stays consistent for the site user.

Varnish loads the static page from the cache using ESI. ESI replaces small dynamic portions of the Magento system backend. The cache then pulls a small section of the website from the Magento platform.

The technique avoids loading the whole site from the origin. It maintains website features without compromising total site speed capabilities.

Does Core Web Vitals affect HTTPS and Varnish in 2025?

Google swapped First Input Delay with Interaction to Next Paint (INP) in March 2024.

INP measures the slowest tap, click, or key press during a visit. TLS 1.3 and Varnish cut Time to First Byte. They shrink render-blocking resources and lower INP scores. Better INP meets the Page Experience system. It still influences ranking.

Quick facts:

• The INP target score sits below 200 ms for good UX.

• TLS 1.3 removes a handshake round. So the server response starts sooner.

• Varnish serves cached HTML from RAM. It avoids database calls and PHP execution.

• Sites moved to Varnish plus TLS 1.3 in 2025. These sites saw a median INP drop of 35%.

How HTTPS and Varnish Boost Search Engine Standing?

1. Core HTTPS Security Signal for Rankings

• Google confirms HTTPS as a direct web ranking signal. Secure sites offer users trust and data protection at all times.

• HTTPS encrypts data between users and your website. The process prevents man-in-the-middle data interception attacks.

• Search engines focus on websites to maintain user online safety measures. HTTPS is a necessity for web credibility confirmation.

• Migrating from HTTP to HTTPS improves website rank. Browsers flag non-HTTPS sites "Not Secure" to all users.

2. Varnish Caching for Speed and Core Web Vitals

• Varnish Cache stores website copies and reduces server load. It serves cached content to users at high speed.

• Faster page load times improve Core Web Vitals key metrics, like LCP. It is important for search positions.

• Varnish improves Largest Contentful Paint (LCP) via quick delivery. Good LCP scores provide positive SEO site impact results.

• Efficient caching minimizes server response times for website user visits. The system creates an improved browsing experience for web users.

3. User Experience: A Prime Ranking Influencer

• Secure and fast websites provide a good user experience for site visitors. Google’s algorithms now reward sites with a good user experience.

• Low bounce rates signal relevant content to all search engines. Faster loading with Varnish keeps users engaged on web pages.

• HTTPS builds user trust, encouraging more site interactions. Users prefer engaging with secure web platforms for their safety.

• Core Web Vitals measure aspects of user experience and web design. Optimizing these with Varnish boosts site visibility.

4. Mobile-First Indexing: Prioritizing Secure, Fast Mobile Sites

• Google now uses mobile versions for all site indexing processes. Mobile site performance remains critical for search engine ranking success.

• HTTPS security is crucial for the integrity of the current mobile website version. Secure mobile experiences build site trust among many mobile users.

• Varnish assures fast mobile page loading for several user requests. Speed has a positive impact on mobile Core Web Vitals scores.

• Responsive design with Varnish caching improves mobile SEO performance. Mobile-native sites gain good rankings on search engine result pages.

5. E-commerce/Magento Advantage: HTTPS and Varnish Synergies

• User trust for Magento stores relies on HTTPS security. Safe checkouts build customer confidence for online store payment transactions.

• Varnish cache enhances the load times of Magento product pages. Faster catalog browsing enhances user shopping flow.

• Magento supports Varnish integration, resulting in store performance. Configure the default.vcl with precision for dynamic content element caching.

• Improved site speed and security boost Magento SEO. It leads to good product visibility, improved website conversion rates.

How to Manage Conflicts Faced with Varnish and HTTPS on Websites?

1. HTTPS and Varnish Conflict

• HTTPS encrypts web traffic for enhanced site security. Varnish cannot inspect this encrypted data by default.

• Varnish offers effective caching for unencrypted HTTP. Encrypted HTTPS traffic bypasses the Varnish caching layer.

• Direct Varnish HTTPS handling is a complex process. The system requires special configurations for decryption.

• Caching encrypted data is not Varnish’s design purpose. Decryption must occur before Varnish processes requests.

2. Usage of TLS/SSL Termination Proxies

• Proxies like Nginx or HAProxy handle the decryption process. They close SSL/TLS connections before Varnish gets requests.

• The proxy sends plain HTTP traffic to the Varnish server. Varnish then achieves successful caching for this traffic.

• The approach maintains HTTPS connections for website clients. Internal communication to Varnish becomes plain HTTP.

• Nginx uses its ssl_certificate and ssl_certificate_key directives. HAProxy uses bind *:443 ssl crt specific commands.

3. Varnish Configuration for HTTPS Traffic

• VCL needs some adjustments. It must handle X-Forwarded-Proto headers for accuracy.

• Set the X-Forwarded-Proto HTTP header in the proxy server. It informs Varnish of the original request's scheme type.

• Use req.http.X-Forwarded-Proto == "https" in your VCL. It helps Varnish make sound HTTPS-aware decisions.

• Make sure that Varnish respects the Vary: X-Forwarded-Proto HTTP header. It prevents mixed-content issues.

4. Mixed Content and Redirect Handling

• Mixed content occurs with HTTP resources on HTTPS pages. Browsers may block many insecure webpage resources.

• Varnish can rewrite specific URLs in server responses. Use regsub() in vcl_deliver for this important function.

• Rewrite all http:// links to https:// within HTML. It confirms that all content gets served through the HTTPS protocol.

• Redirect all incoming HTTP traffic to secure HTTPS. Use a permanent 301 redirect at the proxy level.

5. HTTPS Caching Testing and Verification

• Use the varnishstat utility to scan cache hits. The tool shows key Varnish server performance metrics.

• Inspect Varnish server logs with varnishlog for issues. Look for Hit or Miss Varnish cache status codes.

• Use browser developer tools for website validation. Verify X-Varnish headers in all network responses.

• Check Cache-Control and Vary HTTP response headers. These headers direct Varnish caching patterns for content.

Tips to Improve Your Magento 2 Store Search Engine Ranking

1. User-Native Product URLs

• Magento 2 uses a long product URL because it adds store codes. This makes it look unprofessional and hard to interpret.

• URLs with shorter names and fewer folders rank better. In theory, simpler URLs achieve better results. Even a user with no technical knowledge can understand these.

2. Canonical Tags to Mark Duplicate Pages

• Duplicate content is a strict no for search engine ranking. You might reuse content across pages. Yet search engines can penalize the practice.

• Add canonical tags to mark the preferred version.

3. Image Loading Optimization

• Optimize images to load fast. If your website does not load in three seconds, something happens. 53% of customers leave your website. It harms your ranking.

• Name each image file with accuracy. It helps search engines scan it. Add alt text for every image. So crawlers understand the graphic. Compress images in a lossless format to cut the size.

4. Link Internal Pages for SEO Hierarchy

• Internal page linking can boost SEO rankings. If a visitor reads one page, link it to another on your website. It expands knowledge.

• Search engine ranking remains critical for Magento, as it provides exciting capabilities. An SEO boost pushes store owners to keep updating their websites.

FAQs

1. How does HTTP/3 adoption change Varnish caching?

HTTP/3 moves traffic to QUIC over UDP. Varnish continues to listen for HTTP/1.1 and HTTP/2. It occurs behind a TLS terminator. HTTP/3 at NGINX or HAProxy termination helps forward the request to Varnish. It maintains cache hit logic and allows browsers to enjoy faster handshakes.

2. Can Varnish help improve Interaction to Next Paint (INP)?

Yes. Varnish reduces server processing, which lowers Time to First Byte. A lower TTFB leads to a shorter render start, decreasing worst-case INP. Combining Varnish with a lightweight theme/reduced JS achieves Google's sub-200 ms target.

3. What is the safest method to renew thousands of TLS 1.3 certificates?

Automate renewal with ACME and a central vault. Use short-lived certificates. Push them through an API to all edge nodes. Reload NGINX in a graceful manner. A vault removes manual key handling. It blocks expired certificates.

4. How do edge CDNs integrate with Varnish for global SEO gains?

Place the CDN in front. Let it cache static assets and keep Varnish for HTML fragments. Set Cache-Control: s-maxage for CDN and max-age for browser. Edge nodes cut latency for users far from the origin. It boosts Core Web Vitals and rankings.

5. Will post-quantum TLS break Varnish workflows?

No. Post-quantum key exchange happens in the TLS layer. It doesn't happen inside Varnish. Close encryption at the front proxy. Use one that supports PQC hybrids. Then forward plain HTTP to Varnish. Cache logic stays unchanged.

6. How do I test ESI fragments without risking cache poisoning?

Use a staging host that mirrors production VCL. Load pages with debug headers (X-Varnish, X-Cache). It confirms fragment aging. Run security scans for unescaped user input. Check any ESI inclusion. Push changes only after passing these checks.

Summary

HTTPS and Varnish help enhance search engine ranking and performance. Secure TLS and caching speed up sites and boost trust. Below are the main highlights from the article:

1. Enable TLS 1.3 to cut handshake time overhead. Serve pages over HTTPS to gain ranking weight.

2. Deploy Varnish 7.5 to cache HTML in memory. Reduce backend load and shrink Interaction to Next Paint.

3. Combine Varnish and TLS for faster first-byte time. Improved Core Web Vitals scores lift search visibility.

4. Use Edge Side Includes to cache dynamic page fragments. Serve personalized sections without rebuilding full pages each visit.

5. Keep URLs short and descriptive to support crawl efficiency. Link internal pages to distribute authority and guide visitors.

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