Guide

JSON Formatter vs JSON Repair

A formatter makes valid JSON easier to read. A repair tool tries to turn almost-JSON into valid JSON before formatting it.

Formatter

A JSON formatter expects valid JSON input. It parses the document and prints it with consistent indentation, line breaks, and spacing. Formatters are best for readable logs, API responses, fixtures, config files, and reviewing nested objects that already parse correctly.

Validator

A validator answers one question: is this strict JSON? It should fail fast on comments, single quotes, unquoted keys, trailing commas, Python literals, and other non-JSON syntax. Validation is the right first step when you need confidence that another parser will accept the document.

Repair tool

A repair tool is for almost-JSON: data that has a clear intended structure but contains syntax from JavaScript, Python, markdown, or human comments. Repair can convert the text into strict JSON, then format the result so it is easier to inspect.

Minifier

A minifier removes unnecessary whitespace from valid JSON. It does not fix broken syntax. Use minification when payload size matters or when copying a compact value into an environment variable, query parameter, or command-line example.

Which tool should you choose

Use Validate when you need a yes or no answer. Use Format when the input is already valid but hard to read. Use Repair when JSON.parse fails and the source is copied from a JavaScript object, LLM answer, config comment, or hand-edited snippet. Use Diff when you have two valid or repaired documents and need to understand what changed.

Risk of automatic repair

Repair tools can fix syntax, but they should not decide business meaning. If a repair changes quotes, comments, or commas, the intent is usually clear. If it has to guess a missing bracket, field name, or value, review the output carefully before using it in production.

Practical workflow

For messy input, repair first, format second, validate third, and compare against a known-good example if the payload controls application behavior. This sequence gives you readable output without skipping the final strict parser check.