draw.io (diagrams.net) is a completely free, open-source diagramming tool: flowcharts, UML, network diagrams and wireframes, with real-time multi-user collaboration, and diagram data stored in your own chosen location (browser, Google Drive, Dropbox) rather than on draw.io's servers.
Entirely free and open source (Apache 2.0): unlimited diagrams, all features, no registration required. Only paid option is custom-priced Confluence/Jira integration for embedded diagramming in Atlassian products.
Anyone needing a genuinely free, full-featured diagramming tool without an account or subscription, especially those with data-residency concerns since files never touch draw.io's own servers.
Diagram data is never stored on draw.io's servers by default: it stays in the browser or wherever you choose to save it (Google Drive, local disk), a real advantage for privacy-conscious or compliance-sensitive work.
Free online software for making flowcharts and diagrams.
