Concepts: an infinite canvas where every stroke stays editable
Concepts draws in vector on a canvas without edges: any stroke can be moved and recoloured later. We look at who needs that and who it hinders.
Concepts differs from the rest of this list in how it works, not in what it offers. A stroke here is not pixels on a layer but an object: select it, move it, change its weight and colour an hour after drawing it.
What it gives you
Edits without redoing. Got the angle of a line wrong — you move the line rather than erase and redraw. For diagrams, floor plans and interface sketches this changes working speed several times over.
A canvas without edges. It is not defined in pixels: you can pan across and keep drawing, then keep drawing again. The thought never hits the edge of the sheet.
Scale without quality loss. Vector enlarges indefinitely — a rough sketch can be zoomed into and detailed without thinking about resolution.
What it costs
Being wrong for painting. A brushstroke is not expressible in vector: texture and blending are poor, and anyone arriving for watercolour will be disappointed on the first layer.
A paid tool pack. The free version works, but some brushes, layers beyond a few, and certain export formats sit behind a subscription or a one-time purchase.
Who it is not for
Anyone painting pictures. This is a designer's and sketcher's instrument, not a painter's, and it should not stand in for ibis Paint.