Definition
Secure Access Service Edge, a term coined by Gartner in 2019, describes a cloud-delivered architecture that converges WAN networking (SD-WAN) with security services (firewall, secure web gateway, CASB, ZTNA) into a single platform delivered from points of presence near the user. SASE replaces the traditional pattern of users connecting through a corporate VPN to a centralized data center with a model where users connect to the nearest SASE edge, which applies policy and routes them onward.
How VPN Fits In
SASE includes VPN-like functionality but reframes it. Rather than a user connecting to a corporate gateway and gaining broad network access, the user connects to a cloud edge that applies Zero Trust authorization to each individual application request. The result is faster (the edge is geographically close), more granular (per-app rather than per-network), and easier to scale (no central gateway choke point).
Vendors and Adoption
Major SASE platforms include Cloudflare One, Zscaler, Palo Alto Prisma Access, Cato Networks, and Netskope. Adoption has accelerated since 2020, driven by the work-from-home shift and the inadequacy of traditional VPN concentrators at sustained-high-load remote work. SASE is increasingly the framework that replaces enterprise VPNs in large organizations, while consumer VPNs remain a separate product category.