onDevTools JSON Formatter

What onDevTools JSON Formatter is

onDevTools JSON Formatter is a free web tool for formatting, validating, querying, comparing, and transforming JSON in a browser. It can pretty-print or minify JSON, use 2-, 4-, or 8-space indentation, and sort keys alphabetically. Parsing supports strict RFC 8259 / ECMA-404 JSON and JSONC comments and trailing commas, but not JSON5. Schema checks use JSON Schema Draft 2020-12 and report violations with JSON Pointer paths.

The tool’s JSONPath engine supports wildcards, recursive descent, slices, and filters. It can compare two documents side by side and produce a JSON Merge Patch. Transformation options include flattening or unflattening data and removing null or empty values. A collapsible tree view provides full-text search and copying of a node value or its JSON Pointer path. The maker says parsing, validation, schema checks, diffs, and transformations run locally in the browser rather than uploading JSON. The tree view and JSONPath can slow noticeably above about 1 MB or 50,000 nodes; streaming and JSON Lines are outside its scope. Large numbers may lose precision above 2^53 − 1, so the maker recommends storing 64-bit IDs as strings. The free plan costs nothing, and no account is required.