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How to Remove Sensitive Data from JSON and API Responses

JSON is easy to read, but sensitive information can remain deep inside nested objects and arrays. Review key names and metadata as well as values.

Flow of masking and checking keys and values while maintaining JSON hierarchy
Flow of masking and checking keys and values while maintaining JSON hierarchy

Search for confirmation target by key name

Typical items to be checked are apiKey, accessToken, secret, password, cookie, email, phone, and address. However, since there are unique abbreviations and Japanese keys, you cannot rely on automatic determination based on the key name alone.

Even seemingly safe values like requestId or timestamp can become identifiers that can be matched against internal logs. Replace it if it is not needed for sharing purposes.

Steps to safely process JSON

  1. Separate HTTP headers and cookies and copy only the response body for sharing.
  2. Verify credentials, personal information, and internal identifiers as both keys and values.
  3. Replace strings with safe sample values and numbers with placeholders that preserve their digit count. Keep null and Boolean values when they are needed to test behavior.
  4. Check that it can be parsed as JSON after formatting and that no actual data remains in the second half of the array.

Why Data Types Should Be Preserved

original typeSafe replacement example
Strings"CUSTOMER-001" → "string001"
integer987654 → 123456
Decimal number1250.75 → 1234.56
Boolean or nullKeep the value when it is needed to test behavior

Pay attention not only to the JSON itself, but also to the URL, developer tools header, and file name that appear in the screenshot.

Try It in Your Browser

Your input is processed entirely in your browser. Keep the original data, review the output, and only then save or share it.

Open JSON masking tool