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JSON Formatter & Validator
JSON Formatter & Validator
What is this tool?
A combined utility for two common developer tasks: formatting and validating JSON, and encoding or decoding Base64 strings. Paste in raw or minified JSON to get a readable, indented version with validation errors flagged, or switch to the Base64 mode to convert text to and from Base64 encoding.
When to use it
- Formatting a minified API response so it's readable
- Checking whether a JSON config file is syntactically valid before deploying it
- Debugging a "malformed JSON" error by locating the exact issue
- Decoding a Base64 string from an API token or embedded data URI
- Encoding text or small data into Base64 for use in a config or script
How to use it
- 1Open the JSON Formatter & Validator.
- 2Paste your JSON into the input box to format and validate it, or switch to Base64 mode for encoding/decoding.
- 3For JSON: review the formatted output and any validation errors shown.
- 4For Base64: paste text to encode, or a Base64 string to decode.
- 5Copy the result for use in your project.
Frequently asked questions
Will this tool tell me exactly what's wrong with invalid JSON?
It flags that the JSON is invalid based on standard parsing rules, which typically helps you locate the problem, such as a missing comma or bracket.
Is my API response data uploaded anywhere?
No. Formatting and validation happen entirely in your browser using JavaScript.
Can I use this to encode a file, not just text?
The Base64 mode is designed for text input. For files, check whether another KIOTOOLS tool fits your specific format.
Does it support JSON with comments or trailing commas?
No, it follows strict JSON syntax, so comments and trailing commas will be flagged as invalid.
Is there a cost to use this tool?
No, it's completely free with no sign-up required.