ToolzyLab
Pretty-print, validate, inspect and minify JSON instantly in your browser. Paste raw JSON, upload a file, detect errors with line and column info, explore the structure in tree view, and download the cleaned result with zero uploads.
Clean messy JSON, catch syntax issues, see instant validation status, locate the broken line, and inspect nested objects with a compact professional interface built for developers.
Paste JSON, upload a .json file, or drop text here to format and validate instantly.
📄 .json files · ⚡ instant parse · 🧠 structure stats · 🔍 tree view · 🔒 no uploadWrite or paste raw JSON on the left, then inspect the beautified result on the right.
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Expand objects and arrays to inspect nested keys and values quickly.
It parses your JSON in the browser, shows formatting errors, highlights the broken line, counts structural stats, and generates clean pretty JSON or minified JSON without sending anything to a server.
Use Pretty Print for debugging and readability, then use Minify JSON when you want the smallest payload. Turn on key sorting when comparing API responses or config files.
JSON formatting changes whitespace around a parsed value; validation checks grammar, not an API's business rules. Load or paste a document, choose indentation, key sorting, Unicode output, live validation, and tree search, then inspect duplicate keys, number precision, escaped characters, and schema requirements before using the result.
Objects, arrays, strings, numbers, true, false, and null are valid values. Object names and strings require double quotes; comments, trailing commas, NaN, Infinity, undefined, and functions are not part of standard JSON. A syntax error position is a starting point; the actual missing quote or comma can be earlier.
Object member order is not a dependable business contract, though some signing or diff workflows use canonical serialization. Escaped Unicode and literal characters can represent the same string, while numbers beyond a runtime's safe integer range may lose precision during parsing. Store large identifiers as strings when the producer and consumer require exact digits.
Grammar validation does not prove required fields exist, enum values are allowed, URLs are safe, or nested shapes match the contract. Use JSON Schema or application validation, protect secrets before pasting payloads, and minify only when compact transport is actually useful.
Validate syntax, then validate the data contract and sensitive content separately.
Technical references: RFC 8259 JSON specification MDN JSON.parse reference
Common causes include single-quoted strings, unquoted keys, trailing commas, comments, malformed escapes, missing delimiters, and non-JSON values such as undefined or NaN.
It should change only insignificant whitespace, but parsing and reserialization can expose duplicate-key or number-precision problems. Compare critical values.
Standard JSON does not include comments. Some tools accept JSON-like extensions, but those files may fail in strict APIs and parsers.
Sort for stable human diffs only when member order is not part of a signing, canonicalization, or application-specific process. Arrays must not be sorted casually.
JavaScript numbers cannot exactly represent every large integer. Preserve identifiers or high-precision decimal values as strings or use a parser designed for arbitrary precision.
No. The API can require particular fields, types, formats, ranges, and authentication. Validate against the documented schema and endpoint rules.