Best diagram app for…
Start from what you're making and where it has to go. An app that's perfect for a quick sketch in a meeting can be the wrong one for a diagram that lives next to your code, so each guide names the facts that decide it, gives the reason for every pick and checks every app that could fit against the same facts.
Best free diagram app for work
Which free diagram app am I allowed to use at work?
draw.io, Excalidraw, yEd, Lucidchart
Best diagram-as-code tools
Which tool lets me keep diagrams next to my code?
Mermaid Chart, PlantUML, D2, Eraser
Best AI diagram generators
Which app turns a paragraph into a diagram?
SVG Diagram, Napkin AI, Excalidraw, Eraser
Best whiteboard apps for diagrams
Which whiteboard is best for sketching diagrams together?
Excalidraw, tldraw, FigJam, Miro
Best Visio alternatives
What can replace Visio and still open my .vsdx files?
draw.io, Lucidchart, SmartDraw, EdrawMax
Best diagram apps that work offline
Which diagram app works without the internet?
draw.io, Excalidraw, PlantUML, tldraw
There's no best diagram app overall. The right one depends on how you like to draw, who else edits the diagram, and where it has to end up.