Formatting, Validating, and Minifying JSON
What this tool does
JSON is the default format for API responses, config files, and data exchange, but raw JSON often arrives as one dense line. This tool takes any JSON you paste and re-prints it with consistent indentation and line breaks so nested objects and arrays become readable. At the same time it validates the input and reports how many keys it contains, how deep the nesting goes, and how large the input is.
When to use it
Reach for it when an API returns a minified payload you need to inspect, when a config file won't parse and you have to find the offending character, or when you want to shrink a readable file back down for production. Switch between Formatted and Minified in Settings and copy whichever fits the moment — the indented version for debugging and documentation, the single-line version for transmission or embedding. Two things turn up inside such a payload again and again: an access token, which the JWT decoder splits into readable claims, and epoch fields such as exp or createdAt, which the Unix timestamp converter turns into an actual date.
Example: minified to indented
Paste {"user":{"name":"Ada","roles":["admin","editor"],"active":true}} and the output expands into a nested block where user holds name, a roles array with two entries on their own lines, and active: true kept as a boolean rather than a quoted string. The check line then reports 4 keys and a depth of 3. Choose Minified in Settings to return it to the compact single-line form whenever you need it back.
Notes and edge cases
Validation runs as you type, so a missing comma, an unclosed bracket, or a stray trailing comma is flagged with the line and column where parsing failed. Standard JSON rules apply: keys and strings need double quotes, and comments are not allowed, so formats like JSONC won't pass. When a config file genuinely needs comments, YAML is the usual answer, and the YAML ↔ Properties converter handles that family. Large payloads format fine, though very deep or very long structures produce a long, scrollable result. Numbers, booleans, and null keep their types intact instead of being coerced into strings.