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JSON formatter
Format, validate, and inspect JSON without leaving the browser. This JSON Formatter helps developers clean API responses, spot syntax errors, and switch between readable and compact JSON output.
Last reviewed
June 23, 2026
When an API returns a dense one-line response, paste it into the formatter to expand nested objects and arrays, then validate the structure before using it in code or documentation.
The tool parses the input as JSON, reports parse errors when the input is invalid, and serializes valid data with the selected spacing or minified output mode.
JSON is sent to DevTool House servers to format or validate it and is not stored once the result is returned. Even so, avoid pasting production secrets, tokens, or private customer data into any online tool.
The formatter checks JSON syntax and structure. It does not validate custom business rules, API schemas, authentication signatures, or semantic correctness.