JSON formatter
Format, validate, query, diff, and convert JSON — up to 50MB.
Paste JSON into the input panel, then click an action below.
About this tool
This is the JSON formatter that stays out of your way. Paste in anything from a small config to a 50 MB log dump — the parser runs in a Web Worker so the page doesn't freeze. Format with 2-space / 4-space / tab indentation, minify back to one line, or switch to a collapsible tree view that lets you explore nested structures without scrolling. The diff mode compares two JSON blobs structurally, so reordered object keys don't produce false positives — only real differences show up. Convert an array of flat objects straight to CSV in one click.
Frequently asked questions
What's "semantic diff" and why should I care?
A text diff between two JSON documents flags every reordered object key as a difference, which is usually noise. The semantic diff here compares by structure and keys, so {"a":1,"b":2} and {"b":2,"a":1} show as equal — only real changes appear.
My JSON has comments or trailing commas. Will it parse?
Strict JSON doesn't allow either, but many real-world files (tsconfig.json, VS Code settings) use them. Toggle "Strip comments" and "Allow trailing commas" under Options and it will parse, then emit strict JSON as output.
Where's JSON Schema validation?
Coming in a follow-up build — we're vendoring Ajv for proper Draft 7+ support. JSONPath queries and YAML/TOML conversion are queued in the same phase. The chips on the page mark them as coming.