Canva
Header images, social graphics, Notes images and simple brand kits
Excalidraw
Our verdict: The fastest way to turn a paragraph of explanation into a simple diagram: draw boxes and arrows, export a PNG, and add it to your post like any image. The free web app saves drawings in your browser's storage, which can be cleared, so save a file of anything you'll want to edit later.
Best for
Quick hand-drawn-style diagrams and process sketches to drop into posts
Pricing
Free and open source (MIT license); optional Excalidraw+ at $6/user/mo with a 14-day free trial.
Source: official site (plus.excalidraw.com/pricing) + github.com/excalidraw/excalidraw README
Website
Last checked
2026-10-27
Note: Exports PNG, SVG and an open .excalidraw file. For Substack, add the exported PNG to your post as an image.
Disclosure: We have no affiliate relationship with this vendor. StackKit is independent and not affiliated with Substack Inc. Spot an error? Email hello@stackkit.ink.