JSON validator and editor

Paste or upload JSON to validate it with the precise line and column of any syntax error, then switch between a formatted code view and a collapsible tree — the two views a full JSON editor gives you, without the upload. Object keys repeated within the same literal are flagged, since JSON.parse silently keeps only the last one. Sort keys, choose an indent width, search by key or value, and export the result as a file, all locally in your browser.