JSON Validator

Valid object example

Input: {"name":"app","enabled":true}

Output: A success state plus a prettified JSON block with clean indentation.

Broken JSON example

Input: {"name":"app",}

Output: An invalid JSON error because trailing commas are not allowed in strict JSON.

API response cleanup

Input: A minified one-line JSON API response

Output: A formatted structure that is easier to inspect during debugging.

The validator says the JSON is invalid but it looks fine

Cause: JSON can fail because of small syntax details such as smart quotes, trailing commas, or hidden characters.

Fix: Check punctuation carefully and paste as plain text if the content came from a rich-text source.

The output is valid but not what I expected

Cause: The JSON may parse correctly while still containing the wrong keys, nesting, or values for your application logic.

Fix: Use validation to confirm syntax first, then inspect the formatted structure for semantic correctness separately.

I need comments in my config file

Cause: Strict JSON does not allow comments even though some config ecosystems tolerate comment-like extensions.

Fix: If your target system requires strict JSON, remove comments or switch to a format designed for commented configs such as YAML where appropriate.

What kinds of JSON errors does this tool catch?

The validator catches syntax issues such as missing commas, unmatched braces or brackets, invalid quotes, malformed values, and other parsing errors that prevent the input from being read as valid JSON. If the data cannot be parsed, the tool reports it immediately.

Can it format valid JSON too?

Yes. When the input is valid, the tool outputs a prettified, indented version that is easier to read and inspect. This is useful when you receive minified JSON from an API or when you want to clean up a large object before editing it further.

Why is JSON validation useful in API development?

APIs depend heavily on valid JSON for requests and responses. A single syntax error can break a request body or make debugging much harder. Validating JSON before sending or saving it helps catch errors earlier and keeps integration work moving faster.

Does JSON allow comments or trailing commas?

Standard JSON does not allow comments or trailing commas. Some tools and config systems accept extended JSON-like formats, but if you are working with strict JSON, comments and trailing commas will cause validation to fail.

Can I use this for configuration files too?

Yes. Many applications and deployment systems use JSON-based config files. This validator is useful for checking those files before they are committed, deployed, or passed into another system that expects strict JSON syntax.