JSON Formatter

A JSON formatter takes raw JSON — often received as a single-line API response or a minified config — and renders it with consistent indentation so you can read it at a glance. This tool also validates the input: if the JSON is malformed it shows the exact parse error rather than silently producing no output.

When to use pretty vs minify

Use pretty print when debugging API responses, reviewing webhook payloads, or reading configuration files. Two-space indent is the JavaScript convention; four-space matches Python's default json.dumps(indent=4). Use minify when pasting into a <script> tag or a database column where you want compact storage without whitespace overhead.

Common JSON issues

Trailing commas ([1, 2,]) are not valid JSON — they are valid in JS object literals and JSONC but not in JSON spec. Single-quoted strings fail too; JSON requires double quotes. undefined, NaN, and Infinity are not valid JSON values — they will silently serialize to null in JSON.stringify. This formatter catches all of these at parse time.

For large API responses, minifying before storing in logs reduces storage costs significantly. A 10KB pretty-printed response is often 6–7KB minified. At scale — millions of log entries — that difference is measurable.