How it works
Every tool is a static web page. When you paste text or open a file, the work happens in JavaScript inside your browser tab. There is no server-side processing and no account, and the pages make no network requests with your data. Page views are counted with Cloudflare Web Analytics, which uses no cookies, does no cross-site tracking and never sees what you type, paste or drop into the tools.
The repair tool reads your input twice. A forgiving scanner first records each problem it sees, such as a trailing comma, a Python None or a cut-off string, together with its position. The text is then rebuilt as strict JSON and checked with a strict parser before you see it, so the output is always valid JSON or you get a clear message saying why it could not be mended.
Built with
- jsonrepair for the structural part of the repair.
- CodeMirror for the editors.
- yaml for YAML parsing and output, and Papa Parse for CSV parsing.
- Archivo and Martian Mono typefaces, served from this site.
The strict parser, error explanations, diffing, flattening and conversion logic were written for this site.
Sister sites
JSONMender sits alongside a few other single-purpose, privacy-friendly tool sites; they are listed in the footer.
Questions about how your data is handled are answered on the privacy page.