JSON Flattener/Unflattener

THE PRACTICAL GUIDE · NORMANDIN SYSTEMS

Get more from JSON Flattener/Unflattener

JSON Flattener/Unflattener helps you flatten or rebuild nested objects in JSON. Flattening represents nested paths as keys; unflattening uses those paths to rebuild the hierarchy. This is useful when the information is already available but its structure, presentation, or consistency makes it difficult to inspect. Work with a representative sample first so that you can recognize the expected result before applying the same operation to a larger document. A literal dot in an original key can conflict with a dot used as a path separator. Arrays and empty objects also need deliberate handling. Keep the original input available while reviewing the output. The important check is whether the result still has the intended values and relationships, rather than whether it merely looks neater. Review the separator and array behavior before flattening a whole dataset.

Guide updated October 13, 2026

How to use this tool

1. Place the JSON input in the relevant editor. If the tool compares or combines documents, keep each document in its own input.
2. Select the available settings for the operation you need. Review the separator and array behavior before flattening a whole dataset.
3. Review any syntax errors before interpreting the result. A valid document with the wrong structure needs a different fix from malformed input.
4. Inspect the changed portion and at least one unchanged portion. Keep a copy of the original JSON until the result has been checked in its destination.

SEE IT IN PRACTICE

A worked example

{"a":{"b":1}}

{"a.b":1}

The nested a then b path is written as a single dotted key. Reversing the operation recreates the object hierarchy.

Path collisions and empty containers

The paths a.b and a followed by nested b can become indistinguishable under a dot-based flattening convention. Empty objects and arrays also need an explicit representation if a round trip must preserve them. Try these cases before flattening configuration for an import. If the target system already defines a path convention, use that as the controlling rule.

Decide how arrays appear in paths

A nested object path such as customer.name is straightforward under a dot convention, but a list adds an index or another representation. Confirm the tool’s array behavior before mapping its output to environment variables or spreadsheet columns. Reordering the array may then change path meanings even when the records retain the same IDs. A stable record identifier can be more useful than an array index for later reconciliation.

When this tool is useful

• Prepare flat configuration maps while keeping the underlying structure visible.
• Investigate nested field paths with a compact, reproducible sample.
• Rebuild nested test data before copying data into another application.

Tips for a better result

• A literal dot in an original key can conflict with a dot used as a path separator. Arrays and empty objects also need deliberate handling.
• Review the separator and array behavior before flattening a whole dataset.
• Use a small JSON example to isolate an unexpected result. Add nested objects, arrays, quoted text, and empty values only as needed to reproduce the behavior.

Frequently asked questions