A formatter cannot safely make invalid JSON meaningful by guessing. First run the text through the JSON validator and locate the reported position. Common syntax problems include trailing commas, single quotes, unquoted keys, unescaped newlines, and mismatched brackets. Make one deliberate correction, then validate again.
Once it parses, format it for readability and compare it with the intended schema. Watch for duplicate object keys and values that exceed the receiving system's numeric precision; a visually tidy document can still carry surprising data. Use a trusted local environment for production payloads, or redact tokens and personal fields before pasting them into any external tool.
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