SSL and HTTPS are essential concepts for modern websites. Learn what an SSL certificate does, how HTTPS protects data, the difference between HTTP and HTTPS, common SSL errors, and what website owners should know about secure connections.
SSL is a security technology used to help establish encrypted connections, while HTTPS is HTTP transmitted over a secure connection using TLS. When a website uses HTTPS correctly, information exchanged between the browser and website can be protected against certain forms of eavesdropping and tampering during transmission.
What Is SSL?
SSL stands for Secure Sockets Layer. It was an earlier protocol designed to provide secure communication over computer networks.
Modern websites generally use TLS, or Transport Layer Security, rather than the older SSL protocols. However, the term “SSL certificate” remains widely used when referring to the digital certificates used to establish secure HTTPS connections.
SSL vs TLS: The Important Distinction
People often say “SSL certificate,” but modern secure web connections use TLS. The certificate is used as part of the process that helps authenticate the website and establish a secure connection.
What Is HTTPS?
HTTPS stands for Hypertext Transfer Protocol Secure. It is the secure form of HTTP used to exchange web information over an encrypted connection.
When you visit a website beginning with https://, the browser attempts to establish a secure TLS connection with the website.
A correctly configured HTTPS connection helps protect information moving between the visitor’s browser and the website from being read or modified by unauthorized parties on the network.
HTTP vs HTTPS: What Is the Difference?
| Feature | HTTP | HTTPS |
|---|---|---|
| Protocol | HTTP | HTTP over TLS |
| Encryption | Does not provide TLS encryption | Uses TLS to protect the connection |
| Authentication | No certificate-based server authentication | Uses certificates as part of TLS authentication |
| Browser security | Less protection for transmitted information | Provides a secure connection when correctly configured |
| Modern websites | Generally not recommended for sensitive traffic | Standard approach for modern websites |
How Does HTTPS Work?
HTTPS uses TLS to establish a secure connection between a client and server. The process involves cryptographic techniques that allow the connection to be authenticated and encrypted.
Step 1: The Browser Requests HTTPS
When a visitor enters an HTTPS address, the browser attempts to connect securely to the requested website.
Step 2: The Server Provides a Certificate
The website’s server provides a digital certificate containing information about the site’s identity and public key.
Step 3: The Browser Validates the Certificate
The browser checks whether the certificate can be trusted and whether it matches the website being accessed.
Step 4: TLS Establishes the Secure Connection
The browser and server use the TLS protocol to establish cryptographic protection for the connection.
Step 5: Website Data Is Exchanged
Once the secure connection has been established, HTTP requests and responses can travel through the TLS-protected connection.
What Is an SSL Certificate?
An SSL certificate is a digital certificate used in TLS-based secure connections. It helps a browser verify information about the website and contains a public key associated with the certificate.
Certificates are issued by certificate authorities that browsers and operating systems can trust.
A certificate does not magically make every part of a website secure. Website owners must configure HTTPS correctly and maintain the underlying website, server and applications securely.
Why Does a Website Need HTTPS?
Protects Data in Transit
HTTPS helps protect information exchanged between browsers and servers from certain network-based interception and manipulation.
Authenticates the Website
TLS certificates help browsers verify that they are connecting to the intended domain.
Builds User Trust
Modern browsers visibly distinguish secure and insecure connections, making HTTPS an important part of a professional website experience.
Supports Modern Web Features
HTTPS is required or strongly encouraged by various modern browser features and web technologies.
Is HTTPS Important for SEO?
HTTPS is part of Google’s broader expectations for a secure web, and Google has previously described HTTPS as a ranking signal. However, HTTPS alone does not guarantee high search rankings.
A successful SEO strategy still requires useful content, strong technical SEO, good page experience, crawlability, relevant internal links and other quality signals.
What Happens If a Website Does Not Use HTTPS?
A website operating only over HTTP does not provide TLS protection for the connection. Depending on the browser and circumstances, visitors may also see security warnings or other indicators.
For websites that handle logins, contact information, payments or other sensitive data, relying on unencrypted HTTP is particularly inappropriate.
Common SSL and HTTPS Errors
Certificate Expired
A certificate has a validity period. If it expires and is not renewed, browsers may display a certificate warning.
Certificate Does Not Match the Domain
The certificate needs to cover the hostname being accessed. A mismatch can cause browser security warnings.
Mixed Content
Mixed content can occur when an HTTPS page attempts to load certain resources over insecure HTTP connections.
This can happen with images, scripts, stylesheets, fonts or third-party resources.
Incorrect Server Configuration
Problems with TLS configuration, certificate chains, redirects or server settings can prevent HTTPS from working correctly.
What Is Mixed Content?
Mixed content occurs when a page loaded over HTTPS requests resources using HTTP. This creates an inconsistent security environment because some resources are not protected by the secure connection.
Website owners should update insecure resource URLs to HTTPS whenever the resources support secure delivery.
How to Move a Website From HTTP to HTTPS
- Obtain and install an appropriate TLS certificate.
- Confirm that HTTPS works correctly on the website.
- Update internal HTTP URLs to HTTPS where necessary.
- Fix mixed-content resources.
- Set appropriate HTTP-to-HTTPS redirects.
- Update canonical URLs.
- Check XML sitemaps and internal links.
- Update relevant third-party integrations.
- Verify the website in Google Search Console where appropriate.
- Crawl the website and check for remaining HTTP references.
HTTPS and WordPress
WordPress websites should be configured consistently so that the WordPress address and site address use the correct HTTPS version.
After enabling HTTPS, website owners should also review internal links, images, scripts, stylesheets, canonical URLs, redirects, plugins and third-party integrations.
If your website is built with WordPress, the next useful guide is: How to Secure a WordPress Website .
Does HTTPS Make a Website Completely Secure?
No. HTTPS protects data in transit between the browser and server, but it does not protect a website from every security problem.
A website can still be vulnerable because of outdated plugins, weak passwords, compromised administrator accounts, insecure server configuration, vulnerable applications or malicious code.
HTTPS should therefore be considered one important layer of website security rather than a complete security solution.
HTTPS Best Practices for Website Owners
- Keep certificates valid and properly configured.
- Redirect appropriate HTTP URLs to HTTPS.
- Fix mixed-content warnings.
- Keep WordPress, themes and plugins updated.
- Use strong administrator passwords.
- Enable multi-factor authentication where available.
- Regularly back up important website data.
- Monitor important security and certificate issues.
- Review third-party scripts and services.
- Keep canonical URLs consistent with the preferred HTTPS version.
SSL vs HTTPS: Are They the Same?
No. SSL and HTTPS are related but are not exactly the same thing.
SSL refers to an older security protocol and is also commonly used informally when discussing website certificates. Modern secure connections use TLS.
HTTPS is HTTP operating through a secure TLS connection.
Does Every Website Need HTTPS?
For modern public websites, HTTPS should generally be considered the standard. It provides important protection for visitors and supports a trustworthy web experience.
Even websites that do not collect passwords or payment information can benefit from secure connections because visitors may interact with forms, authentication systems, embedded services and other website features.
HTTPS, Domains, DNS and Hosting: How They Connect
HTTPS does not operate in isolation. A website’s domain, DNS, hosting infrastructure and TLS configuration work together to deliver a secure website experience.
| Component | Role |
|---|---|
| Domain | The human-readable address visitors use. |
| DNS | Helps resolve the domain and associated services. |
| Hosting | Provides the infrastructure that serves website resources. |
| TLS Certificate | Supports authentication and secure connection establishment. |
| HTTPS | Provides HTTP communication through the TLS-secured connection. |
If you are new to website infrastructure, first read What Is DNS? A Simple Guide to How the Internet Finds Websites .
You can also learn the basics of hosting here: What Is Web Hosting? How Websites Work Online .
Frequently Asked Questions
What is SSL?
SSL stands for Secure Sockets Layer. It is an older protocol for secure communication. Modern websites use TLS, although the term SSL certificate is still commonly used.
What is HTTPS?
HTTPS is HTTP transmitted through a secure TLS connection. It helps protect information exchanged between a browser and website.
What is an SSL certificate?
An SSL certificate is a digital certificate used as part of TLS connections. It helps authenticate a website and supports the establishment of a secure connection.
Is HTTPS better than HTTP?
Yes. HTTPS provides TLS protection for the connection, while ordinary HTTP does not provide TLS encryption.
Does HTTPS improve SEO?
HTTPS is one of Google’s known ranking signals, but it is only one small part of SEO. Secure connections do not guarantee higher rankings.
Can HTTPS prevent hacking?
No. HTTPS protects data in transit but does not prevent all website security vulnerabilities, such as outdated software or compromised administrator accounts.
What is mixed content?
Mixed content occurs when an HTTPS page loads certain resources using HTTP. It can create security problems and browser warnings.
Does a WordPress website need HTTPS?
Yes. HTTPS should be used for modern WordPress websites. Website owners should also maintain WordPress, themes, plugins and hosting security.
Trusted External Resources
Final Takeaway
SSL and HTTPS are fundamental parts of modern website security. Although people still commonly say “SSL,” modern secure web connections use TLS.
HTTPS helps authenticate websites and protect information while it travels between a browser and server. It should be treated as a basic technical requirement for a modern website rather than an optional extra.
For website owners, the practical goal is simple: use HTTPS correctly, keep certificates valid, fix mixed content, maintain your website software and protect administrator accounts.
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