draw.io, Excalidraw and Mermaid

Vellum is the default engine. Three others are available from the engine menu on any diagram tab, and a blueprint can mix them.

draw.io

The full draw.io editor, self-hosted. Choose it when you have existing .drawio files, or when you need a stencil that only draw.io has.

Excalidraw

Hand-drawn style, fast for rough thinking. Choose it for sketches that are meant to look provisional.

Mermaid

Diagrams as text. Choose it for sequence diagrams, state charts and gantt charts, and for anything you would rather edit and diff as text.

What you give up

Strata bind to shapes on any engine, so layered detail works everywhere. The difference is elsewhere:

	Vellum	draw.io	Excalidraw	Mermaid
Strata on shapes	Yes	Yes	Yes	Yes
Live collaboration	Yes	No	No	No
Continuum can write to it	Yes	No	No	No
Icon packs	Yes	Own stencils	Limited	No
Podium presentation	Yes	No	No	No

Settings → General sets which engine new diagrams start in.

Switching engines on an existing tab does not convert the drawing. Pick the engine when you create the tab.