SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are cryptographic protocols that encrypt data traveling between a client and a server. When you see the padlock icon in your browser's address bar, TLS is protecting the connection. TLS ensures that data cannot be read or tampered with by anyone intercepting the traffic, even on public WiFi networks.
When a browser connects to an HTTPS server, they perform a "TLS handshake." The server presents its digital certificate (issued by a Certificate Authority), which the browser verifies against its trusted CA list. They then negotiate an encryption algorithm and exchange keys using asymmetric cryptography. Once the handshake completes (typically in one round trip), all subsequent data is encrypted with fast symmetric encryption. The entire process adds only milliseconds to the connection.
Modern TLS 1.3 simplified the handshake to a single round trip and removed support for older, weaker cipher suites. Certificate management has been largely automated by services like Let's Encrypt and Cloudflare, which provide free certificates with automatic renewal.
TLS is not optional in 2026. Browsers flag HTTP sites as "Not Secure." Google uses HTTPS as a ranking signal. API endpoints handling any sensitive data must use TLS. Even seemingly non-sensitive sites benefit from TLS, since it prevents ISPs and network operators from injecting ads or modifying content in transit. For developers, understanding certificate chains, mixed content errors, and HSTS headers is essential for deploying secure web services.
TerminalFeed uses Cloudflare's Universal SSL for automatic TLS on all connections. The Dev/Ops Status panel monitors services that rely on valid TLS certificates. The API Security article covers TLS as a foundational layer of API protection.