Format, validate and minify JSON
The MailDrop JSON formatter takes raw, cramped, or machine-generated JSON and turns it into a clean, readable document with consistent 2-space indentation. Paste any JSON, from a two-line config snippet to a large API response, and format it instantly in your browser. The same page also validates your input and can minify formatted JSON back down to a single compact line for production use.
Validation is where the tool earns its keep. Invalid JSON is one of the most common causes of failed API calls, broken configuration files, and mysterious application errors, and the offending character is often a single stray comma or an unquoted key buried deep in the document. When your input does not parse, the formatter reports a clear error message describing what went wrong, so you can fix the problem instead of guessing.
All parsing, formatting, and minifying happens client-side in your browser, so API responses containing tokens or personal data are never uploaded anywhere. The tool is free with no registration, and it sits alongside MailDrop temporary email in a toolkit built for developers who value privacy.
Drop raw JSON into the input area. It can come from an API response, a log line, a configuration file, or a webhook payload, and it does not matter whether it is minified, badly indented, or all on one line.
Click Format to pretty-print the document with 2-space indentation. Nested objects and arrays are laid out hierarchically, making structure, key names, and values easy to scan and compare.
If the input is not valid JSON, the tool shows an error message describing the problem instead of output. Correct the issue, such as a trailing comma or missing quote, and format again.
Click Minify to strip all unnecessary whitespace and collapse the document to its smallest valid form, which is ideal for embedding in requests, environment variables, or bandwidth-sensitive payloads.
No. Formatting, validation, and minification are performed entirely by JavaScript in your browser. Nothing you paste is transmitted, stored, or logged, which matters because real-world JSON often contains API keys, session tokens, email addresses, and other data you would not want leaving your machine.
Trailing commas after the last item in an object or array, single quotes instead of double quotes, unquoted keys, and raw newlines inside strings account for most failures. JavaScript object literals allow several of these, which is why code that looks fine often fails as JSON. The validator pinpoints such mistakes with an error message.
Two spaces is the most widely used convention for JSON in modern tooling, striking a balance between readability and horizontal space. Deeply nested API responses stay on screen instead of scrolling far to the right, and the output diffs cleanly in version control alongside most project style guides.
Minify when the JSON is consumed by machines rather than people: request bodies, stored payloads, query parameters, and config baked into builds. Removing whitespace shrinks the document without changing its meaning. Format when humans need to read, review, or debug the data. The two operations are lossless and reversible.
Testing webhooks, signup APIs, and notification systems usually produces JSON payloads on one side and emails on the other. Use this formatter to inspect the payloads and a MailDrop disposable email inbox to receive the messages, and you can verify an entire integration without exposing a personal address to test traffic.