Glossary

Canonical definitions for System Architecture.

API (Application Programming Interface)

A set of defined rules and protocols allowing different software applications to communicate.

CDN (Content Delivery Network)

A geographically distributed network of proxy servers providing high availability and performance.

DAU (Daily Active Users)

Unique users who perform at least one action on a platform within a 24-hour window.

DDoS (Distributed Denial of Service)

An attempt to disrupt a server by overwhelming the target with a flood of traffic from many sources.

OOM (Out Of Memory)

A failure state when a process requests more RAM than is physically available.

QPS (Queries Per Second)

The number of request queries processed by an application server or database per second.

Token Bucket

A rate-limiting algorithm that refills tokens at rate r up to capacity b, allowing short bursts while bounding the average rate.

TTL (Time To Live)

A duration after which a cached entry or record is considered stale and evicted.