# draw.io, Excalidraw and Mermaid

> Three alternative diagram engines, when to use each, and what you give up.

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

> [!ACCORDIONS]
>
> === 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 |

## Changing your default

**Settings → General** sets which engine new diagrams start in.

> [!NOTE]
> Switching engines on an existing tab does not convert the drawing. Pick the
> engine when you create the tab.