Gliffy vs draw.io
Comparing Gliffy with draw.io for diagramming in Confluence and beyond: shape libraries, storage of diagram data, Data Center and Cloud support, Apache 2.0 self-hosting outside Atlassian, and which teams gain from switching.

Gliffy, from Perforce, is a diagramming app mostly used inside Confluence and Jira. Pages here cover replacing it with draw.io, inside Confluence or on self-hosted wikis.
Comparing Gliffy with draw.io for diagramming in Confluence and beyond: shape libraries, storage of diagram data, Data Center and Cloud support, Apache 2.0 self-hosting outside Atlassian, and which teams gain from switching.
Moving Gliffy diagrams to draw.io: the mass conversion in draw.io's Confluence app, importing individual Gliffy files, checking converted diagrams, and moving diagrams to a self-hosted wiki such as XWiki if Confluence is also leaving.
Cost of ownership by component: Gliffy for Confluence per-user pricing and Zero Egress, against the draw.io Confluence app or free self-hosted draw.io with a wiki, plus conversion work and support.
For regulated teams that need diagram data to stay put: Gliffy Zero Egress inside Atlassian Cloud compared with self-hosted draw.io on your own servers or desktops, where data goes in each case, and what auditors will ask.

Tell us what you're working on, whether it's a deployment, an audit, a security test or a cyber range. You'll speak with an engineer who can help you scope it.