diagrams.net
diagrams.net
Full diagram editor that works without an account or a saved file
No sign-upOn deviceClassic
Loading page
mermaid.live
Write a diagram as text and watch it render beside you.
The official playground for Mermaid, the diagram-as-code syntax that GitHub, GitLab and Notion render natively. Type ten lines of text and get a flowchart, sequence diagram, ER diagram, Gantt chart or state machine, then export SVG or PNG — or just paste the source into a Markdown file and let the platform draw it. Because it is text, a diagram diffs and reviews like code. Complex layouts are the weak point: you can nudge the syntax, not the boxes.
AltFTool does this too
If you would rather not leave the site, Flow Chart Maker covers the same job here — free, no account, and it runs in your browser.
Open Flow Chart MakerQuestions
Works the moment the page loads. No account, no email, no trial. Layout is decided by the renderer — if it routes an edge badly there is no way to drag it.
No. Mermaid Live Editor does the work inside your browser, so the file never leaves your device — you can load the page, disconnect from the network, and it still works. That makes it a reasonable choice for material containing personal data.
Layout is decided by the renderer — if it routes an edge badly there is no way to drag it.
Alternatives
Same category or same task, ordered by how closely they overlap.
diagrams.net
Full diagram editor that works without an account or a saved file
plantuml.com
Renders UML from a text description, with the source encoded in the URL
sequencediagram.org
Purpose-built editor for sequence diagrams, typed rather than dragged
asciiflow.com
Draws boxes and arrows as plain ASCII you can paste into a comment
excalidraw.com
Hand-drawn-looking whiteboard that opens instantly with no sign-up
lucidchart.com
Polished diagramming with real-time collaboration and smart layout