HTTPS and SSL certificates on a landing page: trust, conversion, and SEO

Open Chrome, type a page address starting with http:// (no "s"), and look at the address bar: "Not secure," spelled out, right next to the URL. No visitor needs to understand what an SSL/TLS certificate is to understand that message — the browser translates it for them. On a paid-traffic landing page, where the whole point is to get a form filled in or a credit card pulled out within seconds, that warning shows up at the worst possible moment: before the visitor has had any chance to judge the offer.

What's actually happening behind the padlock

HTTPS (HyperText Transfer Protocol Secure) encrypts the data exchanged between a visitor's browser and your server: whatever they type into a form, their card number if they buy, even the exact URL they're viewing. Without that encryption, this information travels in plain text and can in theory be intercepted along the way — an unsecured public Wi-Fi network, for instance. The SSL/TLS certificate is what makes that encryption possible and lets the browser show the small padlock instead of the warning.

A study by Joshua Sunshine, Serge Egelman, Hazim Almuhimedi, Neha Atri and Lorrie Faith Cranor (Carnegie Mellon University), published at USENIX Security in 2009, measured how internet users react to browsers' SSL security warnings. The result cuts both ways: a large share of participants ignored or clicked through the warnings that existed at the time, largely because they didn't understand them — but when the researchers designed clearer warnings, cautious behavior increased noticeably. In other words, the warning works better the more explicit it is — and today's browsers, far blunter than in 2009 (a spelled-out "Not secure" rather than a discreet icon), are exactly the kind of signal this research identifies as effective at making a visitor hesitate.

The effect on conversion: not a bonus, a floor

It's worth correcting an idea left over from the early days of e-commerce, when the padlock was marketed as a selling point in its own right ("100% secure site!"). That's no longer true: HTTPS has become the default state of the web (nearly every page Google indexes now has it), so its presence no longer surprises anyone and adds nothing measurable to conversion. Its absence, on the other hand, is still highly visible and costs a lot, precisely because it has become rare and therefore suspicious. It's a classic asymmetry in online trust: a prerequisite that's met is invisible; a prerequisite that's missing jumps out.

The large Stanford study led by B. J. Fogg and colleagues (2003, over 2,500 participants) on the factors behind perceived website credibility points the same way: technical signals of security and seriousness are among the elements internet users notice and cite spontaneously when judging whether a site is trustworthy — alongside overall design and the clarity of the information. A security warning flatly contradicts that credibility judgment, no matter how much care went into the rest of the page.

What this means concretely on a landing page

• Email capture form: a visitor already hesitates to hand over their address; a security warning adds one more reason to abandon, before they've even read the value proposition.
• Credit card field: this is the point of maximum friction. Without HTTPS, some browsers simply block entering a payment method on the page altogether.
• Paid traffic: a visitor arriving via a Google Ads or Meta Ads campaign already carries a baseline doubt ("can I trust this link?"); a browser warning confirms it in the worst possible way.
• Trust badges and reassurance: showing a "secure payment" badge next to the browser's "Not secure" warning creates a visible contradiction the visitor notices immediately — see our article on the trust badges that actually reassure.

The effect on SEO: a real signal, but a small one

On the search-ranking side, Google confirmed as early as August 2014, in an official Search Central blog post, that HTTPS is factored in as a ranking signal. The framing has always been cautious: a "lightweight" signal, affecting a small share of queries and weighing far less than content quality or relevance. In 2026, that description still holds — HTTPS isn't a ranking lever on its own; it acts more as a tiebreaker between otherwise comparable pages. Its real SEO weight has less to do with direct ranking and more with side effects: Google Search Console and rich results behave poorly on mixed content (an HTTPS page that loads an image or script over HTTP), and a visitor who bounces immediately because of a warning drags down the engagement signals Google does observe.

Getting it without thinking about it: the Next.js and Vercel case

Ten years ago, turning on HTTPS meant buying a certificate, configuring it on the server, and manually renewing it before it expired — a classic source of forgotten renewals and outages. That's no longer the case on modern platforms: when a Next.js landing page is deployed on Vercel, as described in our step-by-step deployment guide, the SSL certificate is issued and renewed automatically, both for the default subdomain and for a custom domain connected afterward. There's literally nothing to configure: HTTPS is active from the very first deployment, and any attempt to reach the page over plain HTTP gets redirected automatically. It's one of the quiet arguments in favor of Next.js/Vercel hosting over a traditional shared host, where the certificate can still be a paid add-on or an easy-to-forget checkbox.

On traditional hosting or a self-hosted CMS, keep an eye on three things: make sure the certificate covers the domain and its variants (with and without "www"), set up an automatic redirect from HTTP to HTTPS at the server level, and watch the expiry date if renewal isn't automated (free certificates like Let's Encrypt renew every 90 days). An expired certificate produces the exact same warning as having no HTTPS at all — and it's easier to miss, since the page was working fine the day before.

The mixed-content trap

A common mistake, even on pages properly switched to HTTPS: loading an external resource (image, font, third-party script, iframe) from a URL that still starts with http://. The browser then blocks the resource or shows a "mixed content" warning, which can silently break an image or a tracker without the page's author ever noticing. The rule is simple: every embedded resource must be called over HTTPS, including fonts — a point covered in our article on self-hosting Google Fonts — and any tracking script added through Google Tag Manager.

The takeaway

HTTPS can no longer be managed as a marketing argument: it's a condition of entry, on the same level as reasonable load times or a form that actually works. Its absence drives visitors away before they've read a single line of your offer, and it plants a doubt that neither a great headline nor strong social proof can fully undo. Its presence, on the other hand, goes unnoticed — and that's exactly the point: it frees the visitor to judge the page on what actually matters, the offer itself. The 10 LanderKit templates (€89 each, €229 for the full pack) are built to deploy on Vercel in minutes, HTTPS active from the first deployment, with nothing to configure.