Pretty-print, validate, and inspect JSON documents with optional key sorting and collapse/expand controls.
Pretty-print, validate, and inspect JSON documents with optional key sorting and collapse/expand controls. Pretty-print, validate, and inspect JSON documents with optional key sorting and collapse/expand controls.
JSON (JavaScript Object Notation) is the most common text format for exchanging structured data on the web: configuration files, API responses, log records, document stores, and many more. It is small, human-readable, and trivially machine-parseable, which is why almost every modern service speaks it.
A raw JSON document is rarely useful on its own. APIs and tools often emit a single long line with no whitespace, because that is the shortest representation. When you open such a document in an editor it is hard to scan, hard to spot mismatched brackets, and easy to lose your place while counting braces. A JSON viewer solves this by re-emitting the document with consistent indentation so the structure becomes obvious at a glance.
Pretty printing lets you choose an indent size (commonly two or four spaces) and immediately re-renders the document. Some viewers also let you sort keys alphabetically, which is invaluable when comparing two payloads from the same service: when keys line up vertically you can scan for value differences without matching by position. A stats line that reports the byte count and node count is helpful when you are about to paste a payload into a 1 MB-limited form: it tells you exactly how big it is without opening a terminal.
A viewer is also a validator. The act of parsing with JSON.parse
will throw a descriptive error pointing to the exact line and column
of the first invalid token, so you can immediately see why your
document refuses to load. Most production tools produce errors at
the same point, so the message you see here matches what your
backend, frontend framework, or build pipeline would say.
Use the collapse/expand controls to focus on the top level of a deeply nested document, drill down to the section you care about, and copy the branch you need. If you are debugging an API response, sort keys before comparing so that insertions and deletions at different positions do not confuse your eyes. When in doubt, paste the document into a new tab, tweak the formatting, and use the output as the canonical version for documentation or commit messages.