A JSON formatter can indent objects and arrays consistently and point to syntax mistakes such as a trailing comma or missing quote. It should preserve values exactly: 1, 1.0, strings, booleans, and Unicode escapes may have important distinctions for downstream use even if some parsers normalize representation.
Try malformed input and a valid nested sample, then parse the formatted result with an independent parser. Formatting cannot tell you whether a property belongs in an API payload or meets a schema. Watch for duplicate object names, where RFC 8259 warns that receiver behavior is unpredictable. Save a copy of the original before using automatic repair features.
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