JSON フォーマッタ

JSON をローカルで整形・圧縮・検証。エラーは行と列で正確に表示。データは端末から出ません。

When you need to pretty-print a minified blob, squash whitespace before pasting into a config, or pinpoint exactly where your JSON is broken — open the popup, paste, and read the result. Everything happens inside your browser; nothing is sent anywhere. Key features: - Three modes: **Format** (pretty-print with configurable indent), **Minify** (strip all whitespace), **Validate** (check syntax without rewriting) - Indent picker: 2 spaces, 4 spaces, or Tab - Validate mode shows a compact shape summary (e.g. "object · 4 keys") for valid JSON - On error: a precise **line + column** pointer with the underlying parser message - "Sample" button loads a representative JSON document for quick exploration - One-click copy on the formatted/minified output - Your last-used mode and indent setting are remembered locally No data leaves your device. JSON is parsed and serialized in the browser; nothing is uploaded.