How to Format and Validate JSON Online
Learn how to prettify JSON, fix common syntax errors, validate structure, and minify valid JSON directly in your browser.
JSON is everywhere: API responses, configuration files, webhooks, and exported data. It is useful for software, but a compact JSON payload is hard for people to read and even harder to debug. Formatting turns that dense text into a clear structure; validation confirms that the structure is valid JSON.
Open ToolPorta's JSON Formatter to format and inspect JSON directly in your browser.
What a JSON formatter does#
A JSON formatter, sometimes called a JSON beautifier, adds indentation and line breaks to valid JSON. It does not change the meaning of the data. For example, this one-line object:
becomes easier to inspect when formatted:
Formatting is especially useful when you need to inspect nested objects, compare API responses, or review a configuration change before deploying it.
Format JSON in three steps#
- Paste JSON into the JSON Formatter, or upload a
.jsonfile. - Choose Format / Prettify to add readable indentation.
- Review the result, then copy or download the formatted JSON.
If the formatter cannot parse the input, the JSON contains a syntax problem. Use the error details to identify the line and column, then correct the input before trying again.
How to find and fix invalid JSON#
JSON is strict. The most common mistakes are small but enough to make an entire payload invalid.
| Problem | Invalid example | Fix |
|---|---|---|
| Missing comma | {"name":"Ada" "role":"admin"} | Add a comma between properties. |
| Single quotes | {'name':'Ada'} | Use double quotes for keys and strings. |
| Trailing comma | {"name":"Ada",} | Remove the last comma. |
| Unquoted key | {name:"Ada"} | Put double quotes around the key. |
| Missing bracket | {"items":[1,2,3} | Close every [ with a ]. |
Use ToolPorta's JSON Validator when your main goal is to locate a syntax error. It checks whether the input follows JSON rules and shows where parsing stopped.
JSON formatter vs JSON validator vs JSON minifier#
These tools solve different parts of the same workflow:
| If you need to... | Use this tool |
|---|---|
| Read or inspect nested data | JSON Formatter |
| Locate a syntax error | JSON Validator |
| Remove whitespace for a compact payload | JSON Minifier |
| Transform a document between formats | JSON to XML Converter or XML to JSON Converter |
Start by validating and formatting an unfamiliar payload. Minify only after the JSON is valid and you specifically need a smaller text representation for transport or storage.
Is it safe to format JSON online?#
ToolPorta processes JSON locally in your browser, so formatting and validation do not require sending the payload to an application server. That makes the tool convenient for ordinary development work, but it is still good practice to remove secrets before you paste data anywhere.
Never share API keys, session tokens, passwords, private customer data, or production credentials in screenshots, chat messages, or public issue trackers. Use a safe sample when you need help from another person.
Common JSON formatting questions#
Does formatting JSON change its values?#
No. A formatter changes whitespace and indentation, not keys, values, arrays, or objects. The formatted output represents the same JSON data.
Can JSON contain comments?#
Standard JSON does not allow comments. Some configuration formats look similar to JSON and support comments, but a standard JSON validator will reject them.
What indentation should I use?#
Two spaces is common for compact, readable JSON. Four spaces can be easier to scan in deeply nested documents. Use the convention already used by your project when possible.
Is JSON the same as a JavaScript object?#
No. JSON is a text data format with stricter syntax. JavaScript object literals can use features that JSON does not allow, such as single-quoted strings, unquoted property names, functions, or comments. For code examples, see the JavaScript JSON formatting guide.
Try ToolPorta's JSON tools#
When you need to inspect structured data quickly, start with the JSON Formatter. Pair it with the JSON Validator to resolve syntax errors, then use the JSON Minifier only when you need a compact valid payload.