Check a .canvas board file before you open it
Paste a .canvas file. Your browser reads the JSON, checks every card and connection against the JSON Canvas 1.0 spec, and draws the canvas - free, and nothing is uploaded. A paid run fixes the file or builds a canvas from an outline, and the page checks that file too.
The examples replay saved model runs - the whole page, free.
Your recent runs
What this does, and what it does not
A .canvas file is plain JSON, and most broken canvases are broken JSON: a comma after the last
card, a real line break typed inside a card's text, a quote that was never closed. The page reads
the JSON strictly and points at the line. It then checks every card and connection against the
JSON Canvas 1.0 spec: unique ids,
the four card types and their required fields, whole-number positions and sizes, colours written
as strings, subpaths that start with #, edges whose ends name real cards and whose
sides and arrowheads are spelled as the spec spells them. From the agent skill it adds the
checklist rules the spec leaves out: ids unique across cards and edges, and the literal
\n that shows up as two characters instead of a new line.
The preview is drawn by this page, not by Obsidian, and the page never reads your vault: it sees only the file you paste. Derived from the agent skill @kepano/json-canvas (kepano/obsidian-skills, MIT; see the notice). Board File Fixer is an independent tool, not affiliated with or endorsed by Obsidian (Dynalist Inc.).