JSON OS

JSON OS is a free, browser-based workbench for working with JSON and Markdown — built for developers who don't want to paste sensitive payloads into a random server-side tool.

Everything runs 100% client-side. No signup, no uploads, works offline as a PWA.

Four synced views on the same document:

• Text View — CodeMirror 6 editor with inline "1-click repair" for broken JSON
• Tree View — virtualized, searchable, handles large payloads without lag
• Table View — sortable spreadsheet grid with CSV export
• Chart View — instant bar/line/pie/doughnut SVG charts with SUM/AVG/MIN/MAX and SVG export

Forgiving JSON repair engine — fixes real-world broken JSON: escaped quotes, smart curly quotes, unquoted keys, trailing commas, missing colons, Python/JS literals (True, None, undefined), and stray log-line prefixes.

1-click type generation — turn any JSON payload into TypeScript interfaces, Zod schemas, Python Pydantic models, Rust Serde structs, Go structs, or Draft-07 JSON Schema.

PII & secrets anonymizer — detects emails, passwords, API keys, JWTs, credit cards, and IPs, then redacts, masks, or hashes them before you share a payload.

In-browser API sandbox — send GET/POST/PUT/DELETE requests, import cURL commands from DevTools/Postman, export requests back as cURL, and load responses straight into the workbench for charting or type-gen.

Schema validation & querying — Ajv-based JSON Schema validation (Draft-07 & 2020-12) with templates, MongoDB-style $match filtering, and a side-by-side diff view with configurable ignore rules.

Markdown Studio — live preview with Mermaid diagrams (flowcharts, sequence, Gantt, mindmaps, ER diagrams) and KaTeX math rendering, plus an outline drawer and word-count/reading-time footer.

Built with Svelte 5, Vite, and TypeScript. Heavy computation (parsing, validation, repair) runs in a Web Worker so the UI never locks up on large files. MIT licensed, free for personal, commercial, and enterprise use.

jsonos.online