What it is
Transport Layer Security encrypts data in transit and lets clients verify they are talking to the intended server.
Why it matters
Without TLS, attackers on the network can read or modify traffic. TLS protects logins, APIs, uploads, cookies, tokens, and user data as it crosses the internet.
How it works
During the handshake, the server presents a certificate, both sides agree on cryptographic parameters, and they derive session keys for encrypted communication.
When to use it
Use TLS for all public HTTP traffic, internal service traffic when networks are untrusted, webhooks, OAuth redirects, and custom domains.
Tradeoffs / failure modes
Certificate renewal, hostname validation, mixed content, old protocol versions, and private key handling are common operational issues.
Tiny example
A custom domain points to your SaaS, which automatically provisions a certificate and serves the tenant’s site over HTTPS.
Related guides and systems
See Custom Domains, OAuth2 & Social Login, End-to-End Encryption, Gmail, GitHub, Google Drive, and WhatsApp.
Seen in deeper dives
Capability
Custom Domains
Let users map their own domains to your SaaS with DNS verification and automatic TLS
Capability
End-to-End Encryption
Signal Protocol, key exchange, ratcheting, and encrypted storage for private communication
Capability
OAuth2 & Social Login
Authorization code flow, token refresh, and provider federation for third-party authentication
Case Study
GitHub
The world's largest code hosting platform powered by Git at scale
Case Study
Gmail
The world's largest email service with AI-powered organization and search
Case Study
Google Drive
Cloud file storage and real-time collaboration at planetary scale
Case Study
End-to-end encrypted messaging at planetary scale