How to Format and Validate JSON Without Breaking It
Format, minify, and validate JSON in the browser, then copy or download data.json without uploading the payload.
Invalid JSON fails at the worst moment: a config that will not load, an API body that returns 400, or a copy-paste that looked fine until a trailing comma. Formatting and validating locally catches those problems before the payload leaves your editor.
The Haivix JSON Formatter parses in the browser with the same JSON.parse engine your page uses. You can pretty-print with two-space indent, minify to one line, confirm validity, or inspect a collapsible tree, then copy the output or download data.json. Nothing is uploaded.
Format, minify, validate, or view
Format parses the input and writes pretty JSON with a two-space indent. Minify writes a single line. Both require valid JSON; on success the status line says the payload is valid and formatted or minified.
Validate parses only. On success it copies your raw input into the Output box and reports “Valid JSON.” That is useful when you want to confirm syntax without changing whitespace. Viewer builds a collapsible tree: arrays show length, objects show key count, and nodes shallower than depth two start open.
Copy and Download follow the text Output, not the tree. If Output is empty, Download uses Input instead and saves as data.json.
What counts as JSON here
This is strict JSON. Comments, trailing commas, single quotes, undefined, and JSON5/JSONC extras will fail. The error message comes from the browser parser and usually includes a character position—not a dedicated line highlighter.
Validation is syntax only. It does not check JSON Schema, OpenAPI contracts, or key names. Duplicate keys follow last-wins. Integers outside Number.MAX_SAFE_INTEGER can lose precision after parse, which is a JavaScript limit rather than a Haivix quirk.
When to use a sibling tool instead
Need a spreadsheet from an array of objects? Use JSON to CSV. Inspecting a token rather than a document? Open JWT Studio. Encoding the string for a header or data URI belongs in the Base64 Encoder.
The formatter does not sort keys, run JSONPath, or convert XML or YAML. Keep those jobs in dedicated tools so the JSON you ship is still the JSON you intended.
Checklist before you paste into production
Open the JSON Formatter, paste the payload, run Format or Validate, then copy or download. Work stays in the current tab until you leave or clear it.
- The payload parses as strict JSON (no comments or trailing commas).
- You formatted or minified on purpose, not by accident.
- Copy/download came from Output after the action you wanted.
- Large files were tested; a huge document can exhaust the tab.
- IDs that look like integers were checked if they might exceed safe integer range.
- Schema or API contract checks happened elsewhere if the job required them.