HTTP vs HTTPS: What Is the Difference?

Http vs Https

HTTP and HTTPS are both protocols for transferring data between a browser and a server. The critical difference is security: HTTPS encrypts all data in transit using TLS, while HTTP sends everything as plain text that anyone positioned between you and the server can read, modify, or intercept.

What Is HTTP

HTTP (HyperText Transfer Protocol) is the foundation of data communication on the web. It defines the rules for how browsers request resources and how servers respond. Every webpage you load, every form you submit, and every API call you make over HTTP follows this protocol.

The fundamental limitation of HTTP is that data is transmitted as plain text. Every packet travelling between your browser and the server is human-readable. Anyone on the same network, an ISP, a router operator, or an attacker running a man-in-the-middle attack, can intercept that traffic and read usernames, passwords, credit card numbers, or any other data being exchanged. HTTP provides no way to verify that the server you are talking to is genuinely who it claims to be.

What Is HTTPS

HTTPS (HyperText Transfer Protocol Secure) is HTTP with a layer of encryption provided by TLS (Transport Layer Security). All data exchanged between your browser and the server is encrypted before it leaves your device and can only be decrypted by the intended recipient. Even if an attacker intercepts the traffic, they see only unintelligible ciphertext.

HTTPS also provides authentication. The TLS certificate attached to a domain is issued and signed by a trusted Certificate Authority (CA). When your browser connects to an HTTPS site, it verifies that the certificate is valid, has not expired, and was issued for the correct domain. This prevents attackers from impersonating a website by presenting a forged certificate that the browser would reject.

HTTP vs HTTPS: Full Comparison

How HTTPS Works: The TLS Handshake

Before any encrypted data is exchanged, the browser and server go through a process called the TLS handshake to establish a secure connection. This happens automatically and takes only a few milliseconds on modern hardware and networks.

1. The browser initiates a connection to the server on port 443 and sends a ClientHello message listing the TLS versions and cipher suites it supports
2. The server responds with a ServerHello, selecting the TLS version and cipher suite, and sends its TLS certificate
3. The browser verifies the certificate against a list of trusted Certificate Authorities built into the operating system and browser. It checks that the certificate has not expired, has not been revoked, and was issued for the correct domain.
4. The browser and server perform a key exchange, agreeing on a shared session key using asymmetric cryptography. The private key on the server never leaves the server during this process.
5. Both sides confirm the handshake is complete and switch to symmetric encryption using the shared session key for all subsequent communication
6. All HTTP data transferred in this session is now encrypted and authenticated

Why HTTPS Matters for Users

From a user's perspective, HTTPS provides three fundamental security guarantees that HTTP cannot offer.

• Privacy: All data exchanged between your browser and the server is encrypted. Your ISP, mobile carrier, network administrator, and anyone monitoring the network cannot read the content of your requests or the server's responses.
• Integrity: TLS ensures that data cannot be silently modified in transit. Without HTTPS, a network attacker or ISP could inject advertisements, tracking scripts, or malicious code into pages you receive. HTTPS makes this impossible.
• Authentication: The TLS certificate confirms you are communicating with the genuine server for the domain you requested and not an attacker who has positioned themselves between you and the real server.
• Trust signals: The padlock icon in the browser address bar tells users the connection is encrypted. Its absence, shown as a "Not Secure" warning in modern browsers, causes users to lose confidence and abandon sensitive interactions.

Why HTTPS Matters for Website Owners

Beyond protecting your users, HTTPS has direct practical benefits for anyone running a website or web application.

• SEO ranking: Google has used HTTPS as a ranking signal since 2014. All other things being equal, an HTTPS site ranks higher than an HTTP equivalent. HTTP sites are increasingly penalised as the web shifts fully to encrypted connections.
• Browser warnings: Chrome, Firefox, and Safari all display "Not Secure" warnings for HTTP pages, particularly when they contain forms. These warnings deter users and reduce conversions on any page that asks for input.
• HTTP/2 support: HTTP/2, which offers significant performance improvements through multiplexing, header compression, and server push, requires HTTPS in all major browser implementations. Running HTTP means being limited to the slower HTTP/1.1 protocol.
• Modern web features: Several browser APIs including Service Workers, push notifications, geolocation in some contexts, and the Progressive Web App installation prompt are restricted to secure origins and will not function over plain HTTP.
• Legal and compliance requirements: Any website handling user accounts, personal data, or payment information is expected or legally required to use HTTPS under frameworks such as GDPR and PCI DSS. HTTP is simply not acceptable for these use cases.

Getting an SSL/TLS Certificate

A TLS certificate is required to enable HTTPS on any domain. There are several ways to obtain one depending on your hosting setup and requirements.

• Let's Encrypt: A free, automated, and widely trusted Certificate Authority that issues domain-validated certificates at no cost. Most modern hosting providers and web servers support automatic Let's Encrypt certificate issuance and renewal through tools like Certbot. This is the right choice for the vast majority of websites.
• Hosting provider included certificate: Many hosting platforms including Cloudflare, Netlify, Vercel, and most managed WordPress hosts provision and renew TLS certificates automatically when you connect a domain. No manual steps are required.
• Paid certificates: Commercial CAs offer Organisation Validated (OV) and Extended Validation (EV) certificates that include additional verification of the organisation behind the domain. These display the organisation name in some browser contexts and carry a warranty, but they provide the same level of encryption as a free domain-validated certificate.

Frequently Asked Questions

1. Does HTTPS slow down websites?
   In practice, HTTPS does not meaningfully slow down modern websites. The TLS handshake adds a small amount of latency on the very first connection to a server, typically measured in milliseconds. After that, session resumption and connection reuse eliminate most of this overhead. More importantly, HTTPS is required to use HTTP/2, which loads pages significantly faster than HTTP/1.1 through multiplexing and other optimisations. A well-configured HTTPS site will almost always outperform an equivalent HTTP site.
2. Is a free SSL certificate as good as a paid one?
   For encryption purposes, yes. Free certificates from Let's Encrypt provide exactly the same strength of encryption as paid certificates. The difference lies in the validation process and optional extras. Free certificates are domain-validated, meaning the CA only verifies control of the domain. Paid OV and EV certificates involve verifying the organisation's legal identity. For most websites, a free Let's Encrypt certificate is fully appropriate and indistinguishable to users in terms of security.
3. Can HTTPS connections be hacked?
   The TLS encryption protocol itself is extremely strong and practically unbreakable with current technology when implemented correctly. Attacks on HTTPS typically target weaknesses outside the protocol itself, such as expired or misissued certificates, outdated TLS versions or weak cipher suites, compromised Certificate Authorities, or user behaviour such as accepting invalid certificate warnings. Keeping certificates renewed, using modern TLS versions, and configuring HSTS significantly reduce the attack surface.
4. What is HSTS and should I use it?
   HTTP Strict Transport Security (HSTS) is a response header that instructs browsers to only ever connect to your domain over HTTPS, even if the user types an HTTP URL or clicks an HTTP link. Once a browser has seen the HSTS header, it refuses to make plain HTTP connections to your domain for the duration specified in the max-age directive. This eliminates SSL stripping attacks where an attacker downgrades your connection to HTTP before it reaches the HTTPS redirect. Any site that has fully committed to HTTPS should set the HSTS header with a long max-age value.
5. Does HTTPS protect against all attacks?
   HTTPS protects data in transit between the browser and the server. It does not protect against attacks that occur on the server itself, such as SQL injection or cross-site scripting, which involve the application layer rather than the transport layer. It does not protect against attacks on the user's device. It does not prevent the server from logging your requests or sharing your data. HTTPS is one essential layer of web security but must be combined with secure application development, proper authentication, and other defences for comprehensive protection.

Conclusion

HTTPS is the standard for all modern websites without exception. It protects user privacy by encrypting data in transit, ensures integrity by preventing modification of content, authenticates the server to prevent impersonation, improves search ranking, enables faster HTTP/2 connections, and unlocks modern browser APIs. Getting started requires nothing more than a free certificate from Let's Encrypt, which most hosting platforms now provision automatically. If your site still runs on HTTP, migrating to HTTPS is the single most impactful security improvement you can make. Learn more about SSL and TLS, HTTP headers, and HTTP caching to complete your understanding of secure web communication.