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A full-featured JSON editor with syntax highlighting, real-time validation, auto-formatting, table view, tree view, and error markers — all running locally in your browser.
A JSON editor is more than a text box. A good JSON editor provides syntax highlighting to make the structure visually clear, real-time validation to catch errors the moment you type them, automatic formatting to keep indentation consistent, and structured result views so you can navigate complex JSON without getting lost in brackets. JSON Viewer Pro gives you both tree view and table view so you can inspect the same data in the format that best fits the task.
JSON Viewer Pro's online JSON editor is built on Monaco Editor — the same editor engine that powers Visual Studio Code. It gives you the full VS Code editing experience in your browser: intelligent bracket matching, code folding, find and replace, multi-cursor editing, and instant error markers that underline the exact character where a JSON syntax error occurs. You can format or minify JSON with a single click, and copy or download the result immediately.
Unlike other online JSON editors, JSON Viewer Pro stores everything locally. Your JSON is never uploaded to a server, and the editor works fully offline after the first page load. The editor supports files of any size — large JSON is handled without freezing the browser tab by offloading heavy operations to Web Workers in the background.
A good JSON editor provides syntax highlighting, real-time validation, auto-formatting, and an intuitive UI for navigating nested structures.
Yes. JSON Viewer Pro uses Monaco Editor and Web Workers, so even very large JSON files can be edited without freezing the browser.
Yes. Validation runs in real time with a short debounce and shows error markers on the exact line with a plain-English explanation.
JSON Viewer Pro — all processing runs locally in your browser. Your data is never sent to any server. Free to use, no account required.Privacy Policy·Contact