Format, minify, and validate JSON right in your browser — with the exact line and column when something is wrong.
JSON formatter, minifier, and validator
Paste JSON, then format it, minify it, or validate it — with error line and column when it will not parse. Runs 100% in your browser.
Your JSON never leaves your browser. Formatting, minifying, and validation all run locally on this page — nothing is uploaded or stored.
About this tool
JSON is the language your software uses to talk to itself: API responses, configuration files, webhook payloads, log lines, and data exports are all JSON, and all of them become hard to read the moment they arrive as one long line. JSON Tools is a focused workbench for that moment. Paste in a payload and format it with two-space, four-space, or tab indentation so the structure is visible at a glance. Minify it when you need the smallest possible version for a request body or a config value. Validate it when a parser somewhere is refusing your file and you need to know why. The validator does more than say invalid: when the parser reports a position, the tool converts it into a line and column so you can jump straight to the missing comma, the trailing comma, or the unquoted key that broke the parse. Everything runs locally in your browser using the same JSON parser your browser ships with, so your data is never uploaded, logged, or stored — you can safely check production payloads, tokens-adjacent configuration, and customer exports here. It is deliberately simple: one input, three actions, a clear verdict, and output you can copy straight back into your editor, your API client, or your ticket.
How it works
- Paste or type your JSON into the input box — a snippet, a full API response, or an entire config file.
- Choose Format to pretty-print it with 2 spaces, 4 spaces, or tabs, Minify to strip all unnecessary whitespace, or Validate to only check it.
- If the JSON is invalid, read the status line: it reports the parser message with a line and column whenever the parser provides a position.
- Copy the output from the result panel and drop it back into your editor, request body, or config file.
Frequently asked questions
Is my JSON uploaded to a server?
No. Formatting, minifying, and validation all run in your browser with its built-in JSON parser. Nothing you paste is sent over the network or stored, which makes the tool safe for internal payloads and configuration.
Why does the validator give a line and column for some errors but not others?
The position comes from the browser's own JSON parser. Most syntax errors include a character position, which the tool converts into a 1-based line and column. A few error types, such as an unexpected end of input, may not carry a precise position in every browser version.
What indentation options are available?
You can format with 2 spaces, 4 spaces, or a tab character. Minify removes indentation and all other optional whitespace, producing the compact single-line form.
Can it fix broken JSON automatically?
No — it will not guess at your intent or silently change your data. It tells you exactly where parsing failed so you can fix the real problem, which is safer than an automatic repair that might alter values.
Does formatting change my data?
No. Formatting only changes whitespace. The parsed value is identical before and after; key order is preserved as parsed, and numbers and strings are re-serialized in standard JSON form.