Local tools
JSON utilities that do real work in your browser
Every page below runs a working tool on this device. Each one uses the same parser and engines as the full studio, and each links to the studio when you need profiling, diffing or transformations.
Advanced JSON EditorformatA browser-based JSON editor with Monaco, duplicate-key detection, lossless large numbers, JSONC/JSON5 support, tree and grid views, and a full analysis workbench. Nothing is uploaded.Online JSON ViewertreeView, explore and understand JSON with a lazy tree, table view, structure graph and field statistics. Works locally in your browser with no uploads.JSON FormatterformatFormat and pretty-print JSON with 2, 4 or 8 space indentation, key sorting and precise error positions. Runs entirely in your browser.JSON ValidatorvalidateValidate JSON syntax with exact line and column errors, duplicate-key detection and optional JSON Schema validation. All local.JSON Diff TooldiffCompare two JSON documents structurally, ignore key order or selected paths, match arrays by id, and export RFC 6902 or RFC 7396 patches.JSON Schema ValidatorschemaValidate JSON against Draft 7, 2019-09 or 2020-12 schemas with AJV. See errors at their exact instance paths. Runs locally.JSON to CSV ConvertercsvConvert arrays of JSON objects to CSV with flattened nested columns and clear loss warnings. Runs locally in your browser.JSON Tree ViewertreeExplore JSON as a lazy, virtualized tree with type badges, array counts, paths and pinned nodes. No upload, no account.Large JSON ViewerlargeOpen large JSON files with worker parsing, virtualized views and progressive exploration. Real limits and timings are shown, not marketing claims.JSONPath TesterjsonpathTest JSONPath expressions with filters, slices, unions and recursive descent. Also try JMESPath, JSONata and a SQL dialect. Local and sandboxed.JSON Repair ToolrepairRepair common JSON mistakes: comments, trailing commas, single quotes, unquoted keys and Python literals. See exactly what changed.
These tools do not upload documents. They do not require an account. Heavy operations run in Web Workers where the browser supports them; very large inputs remain bounded by available memory.