Free online JSON flattener. One-click to flatten nested JSON into dot-separated key-value pairs, or restore flattened JSON back to nested structure. Supports custom separators (dot, underscore, slash, etc.) for data processing and API debugging.
TL;DR: Flatten nested JSON into key-value pairs or restore flattened JSON back to nested structure, with custom separator support for data processing and debugging.
This tool runs entirely in your browser. Open DevTools → Network panel and search your input — it appears in no request.
FAQ
JSON flattening is the process of converting a nested JSON structure into single-level key-value pairs. Nested keys are joined by a separator (usually a dot), e.g., {"a":{"b":1}} becomes {"a.b": 1}.
Flattened JSON is useful in many scenarios: data export to CSV/Excel, configuration management, log analysis, API parameter processing, database storage, key path searching, etc. It simplifies access to deeply nested data.
Common separators like dot (.), underscore (_), slash (/), and hyphen (-) are supported. Arrays use bracket notation by default, e.g., items[0].name.
Yes. The tool supports bidirectional conversion — it can flatten nested JSON and also restore flattened JSON back to the original nested structure, including full restoration of arrays and objects.
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