draw.io
FreeFlowcharts and architecture diagrams — no account, no diagram limits
An open-source diagramming tool for flowcharts, architecture diagrams, UML, network topology, mind maps and wireframes. The desktop build works entirely offline with files stored on your own disk. Shape libraries cover AWS, Azure, Kubernetes, Cisco and other major technology icon sets, and exports include PNG, SVG, PDF and re-editable XML.
Why we picked it
Drawing a flowchart has a well-established commercial playbook: three diagrams on the free tier, advanced shape libraries behind a subscription, high-resolution export as a paid feature, files stored in their cloud, and per-seat monthly billing for collaboration.
draw.io removes all of it. Apache-2.0, and unlimited diagrams, every shape library open, exports without watermarks or resolution caps, and no account required.
Install the desktop build rather than relying on the web version. It runs fully offline, and
your files are ordinary .drawio files on your own disk or in a Git repository, never touching a
server. That matters more than people realize for internal architecture diagrams — plenty of
network topologies have been drawn onto someone else's cloud without a second thought.
The shape libraries are an underrated advantage: AWS, Azure, GCP, Kubernetes, Cisco, network equipment and rack diagrams all ship as official-style ready-made shapes, so cloud architecture diagrams need no asset hunting. UML, ER diagrams, swimlanes and BPMN have templates too.
Practical details worth knowing:
- Rich export formats. PNG, JPG, SVG and PDF, with SVG and PDF vector-based so they stay sharp when scaled — genuinely useful for documents and slides.
- Editable exports. When exporting PNG you can include a copy of the diagram, so whoever receives that PNG can drag it back into draw.io and keep editing without a separate source file.
- Good tooling integration. VS Code has an official extension for editing
.drawiofiles directly, and Confluence, Notion and others integrate as well. - A plain-text format.
.drawiois XML underneath, so it version-controls in Git with readable diffs.
To be clear about:
- It leans toward engineering diagrams rather than visual design. Excellent for technical documentation, process descriptions and system architecture; for polished infographics or posters, Inkscape or Penpot fit better.
- Real-time collaboration requires third-party storage such as Google Drive or OneDrive rather than working out of the box. Individuals and small teams rarely need it.
- Desktop downloads live in the drawio-desktop repository's releases — do not grab the source repository by mistake.