The catch-all for cloud-delivered services: SaaS, PaaS, IaaS, FaaS, DBaaS, the consumption model that defines the cloud era.
XaaS (Anything as a Service) is the umbrella term for the cloud-delivery model that replaces buying and operating software with consuming it as a service. The major variants are IaaS (Infrastructure: AWS EC2, GCP Compute), PaaS (Platform: Heroku, Cloud Run), SaaS (Software: Salesforce, Zoom, Datadog, Nova), DBaaS (Database: RDS, Cloud SQL, MongoDB Atlas), and FaaS (Function: Lambda, Cloud Functions). Each layer trades off control for convenience.
Picking the right XaaS layer is a long-term cost decision, not just a short-term convenience one. IaaS gives maximum flexibility but maximum operational burden; SaaS gives instant value but vendor lock-in; FaaS gives unbeatable economics for spiky workloads but limits architectural patterns. SRE teams operating in a multi-XaaS world need observability that crosses all the layers, since incidents now span 'our Lambda called your DB-as-a-Service which fired a webhook to a third-party SaaS.'
See the part of the platform that handles xaas (anything as a service) in production.