Substrata Markup Board
Upload mockups or designs, draw, add shapes, highlight issues, and export results instantly.
Frequently Asked Questions
Is Substrata free to use?
Yes, Substrata is completely free with no login or usage limits.
Are my uploaded images sent to a server?
No. Uploaded images and all drawing/markup happen locally on an HTML canvas in your browser — nothing is uploaded anywhere.
What markup tools are available?
You can freehand draw, add rectangles, circles, and text markup in a choice of colors, then undo individual actions or clear the canvas entirely.
Can I export my markup?
Yes, click Download Canvas to export your annotated image as a PNG file.