mTLS
Mutual TLS: both client and server present certificates to authenticate each other. Standard in service mesh architectures where every service verifies its peers.
What is mTLS?
Mutual TLS: both client and server present certificates to authenticate each other. Standard in service mesh architectures where every service verifies its peers.
mTLS is a intermediate-level concept that sits in the Security Architecture area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "mTLS" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
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See also
Related glossary terms you might want to look up next.
SSL/TLS
Cryptographic protocols that encrypt data in transit between client and server. TLS is the modern successor to SSL. The 'S' in HTTPS.
Service Mesh
A dedicated infrastructure layer for handling service-to-service communication in microservices. Manages load balancing, encryption, and observability automatically.
Zero Trust
A security model that never trusts any request by default, even from inside the network. Every request must be authenticated, authorized, and encrypted regardless of origin.