Free online JSON formatter and validator
Use BrowserStack’s free online JSON formatter to beautify JSON with indentation and line breaks, minify it by removing unnecessary whitespace, or fix syntax errors. Paste your JSON into the editor, review the output, and copy the result. Everything’s free.
The formatter supports everyday tasks such as inspecting API responses, debugging configuration files, and checking nested JSON data. The validator checks your JSON against the syntax rules in RFC 8259, the standard for JSON data interchange.
How to format and validate JSON online
To format JSON online, paste or upload your JSON into BrowserStack’s JSON Formatter and click Format. The tool structures the data for readability and flags syntax errors with line numbers so you can correct them before copying the output.
Follow these steps to format and validate JSON using BrowserStack’s online formatter.
- Paste or upload your JSON: Add your JSON to the input editor or upload a JSON file.
- Choose indentation: Select the indentation level for the formatted output.
- Click Format: Format the JSON to add indentation and line breaks, making nested objects and arrays easier to read.
- Fix any errors: Check the syntax errors and line numbers flagged by the validator. Correct the invalid JSON and format it again.
- Copy or download: Copy the formatted JSON or download the output for use in your application.
The formatter runs in your browser, so you can work with JSON without installing a Chrome extension.
Example of formatting an API response
Let’s say you’re debugging an e-commerce application and need to inspect the API response returned after checkout. The response includes the order status, customer details, purchased items, and payment information, all packed into a single line of JSON. You can use BrowserStack Free JSON formatter to fix this.
Step 1: Paste or upload your JSON
Paste the API response into BrowserStack’s JSON Formatter. For example:
{"orderId":"ORD-10482","status":"confirmed","customer":{"id":7821,"name":"Aarav Mehta"},"items":[{"productId":"P-204","name":"Wireless Mouse","quantity":2,"price":24.99},{"productId":"P-118","name":"USB-C Hub","quantity":1,"price":39.99}],"payment":{"method":"card","status":"paid","currency":"USD"},"total":89.97}Step 2: Choose indentation
Select your preferred indentation level for the formatted output.
Step 3: Click Format
The formatter adds line breaks and indentation (that you can set) to the JSON.
Step 4: Fix any errors
If the API response contains invalid JSON syntax, check the error message and line number reported by the formatter. Correct the issue and format the response again to get valid, readable JSON.
Step 5: Copy or download
Copy the formatted JSON and use it to inspect the API response while debugging. You can quickly locate fields such as status, payment, and quantity without scanning through a long line of data.
Paste, type, upload or fetch JSON from a URL
BrowserStack’s JSON Formatter lets you bring JSON into the editor using the supported input methods.
- Paste JSON: Copy a JSON object or API response and paste it into the editor.
- Type JSON: Enter or edit JSON directly in the input field.
- Upload a file: Upload a saved .json or .txt file containing JSON.
- Fetch JSON from a URL: Import JSON directly from a URL instead of pasting the response manually.
JSON indentation options: 2 spaces, 4 spaces or tabs
The BrowserStack JSON formatter lets you choose indent and how easily you can scan nested JSON.
Two spaces keep the output compact, while four spaces create more separation between nested levels. Tabs work well if your editor uses tab-based indentation.
| Option | Best for | Output size |
|---|---|---|
| 2 spaces | Compact, readable JSON | Smaller |
| 4 spaces | Easier scanning of deeply nested data | Larger |
| Tabs | Teams or editors configured for tabs | Depends on how tabs are displayed and stored |
Example: See how indentation changes JSON readability
Consider this nested JSON object. The data stays the same, but the spacing changes depending on the indentation setting you choose.
The below image shows the formatted output with 2-space indentation.
The following image shows the same JSON with 4-space indentation.
Minify and beautify JSON
Beautifying JSON adds indentation and line breaks to make the data easier to read. Minifying JSON removes unnecessary whitespace to reduce its size, which is useful when sending JSON between applications or using it in production.
For example, the same JSON looks different in each mode.
Beautified JSON
{
"note": {
"from": "Jessy",
"to": "Joe"
}
}Use Beautify when you need to inspect nested data or debug an API response.
Minified JSON
{"note":{"from":"Jessy","to":"Joe"}}Choose Minify when you want to remove formatting whitespace before transmitting or storing JSON.
Copy, download and share formatted JSON
Once you’ve formatted and validated your JSON, you can export the output for debugging or use it in another application.
- Copy to clipboard: Click Copy to copy the formatted JSON and paste it into your code editor, API client, or configuration file.
- Download JSON: Click Download to save the output as a .json file for later use.
JSON validation with line-level error messages
A missing comma or an unquoted key can make a JSON response fail to parse. BrowserStack’s JSON validator checks the structure against the rules in RFC 8259, the JSON data interchange standard and flags syntax errors and reports the line where parsing fails
For example, this JSON is missing a comma after “Jessy”:
{
"from": "Jessy"
"to": "Joe"
}The validator will return an error such as:
Expected ‘,’ or ‘}’ after property value (line 3, column 3)
Since the formatter reports only the first error, fix it and click Format again to reveal the next one.
Before and after: JSON formatter example
A JSON formatter turns a single-line JSON payload into an indented structure that is easier to scan. It changes the layout without changing the data, keys, or values.
For example, consider this user object with a name and a list of roles. The minified version keeps everything on one line, while the formatted version puts each key on its own line.
Tree view for reading nested JSON
Tree view presents JSON as a hierarchy of expandable and collapsible nodes. Instead of scrolling through a long formatted payload, you can collapse objects or arrays you don’t need and expand specific branches to inspect their values.
The tree view also displays key counts for objects, item counts for arrays, and colors different values to make fields easier to distinguish. For example, you can expand tests to inspect individual test results or collapse browsers when you don’t need to check the browser list.
Common JSON syntax errors and how to fix them
Most JSON syntax errors come from single quotes, unquoted keys, trailing commas, comments, or capitalized literals such as True. The BrowserStack JSON Formatter can flag invalid syntax so you can locate the problem, correct it, and format the JSON again.
| Error | Incorrect JSON | Correct JSON |
|---|---|---|
| Trailing comma | {“a”: 1,} | {“a”: 1} |
| Single quotes | {‘a’: 1} | {“a”: 1} |
| Unquoted key | {name: “Ana”} | {“name”: “Ana”} |
| Comment | {“a”: 1 /* value */} | {“a”: 1} |
| Capitalized literal | {“active”: True} | {“active”: true} |
RFC 8259 defines JSON syntax and rejects constructs such as single-quoted strings and trailing commas. See the JSON specification.
When an API response fails validation, paste it into the formatter and check the reported line number. Fix the syntax at that location, then format the JSON again to check whether another error remains.
Steps to fix a JSON parse error
When BrowserStack’s JSON Formatter flags invalid JSON, use the error message to narrow down the problem. It shows the line and column where parsing failed, along with a hint about what the parser expected.
- Jump to the reported line: Check the line and column in the error message, then click Jump to line to go straight to the problem area.
- Inspect the surrounding syntax: Look for a missing comma, an extra comma, mismatched brackets, or incorrect quotation marks. The actual mistake may be on the preceding line.
- Fix the error: Correct the JSON in the input editor. You can also try auto-fix when that option is available, then review the result.
- Validate it again: Click Format to check the updated JSON. If another error appears, follow the same process until the input passes validation.
Auto-repair broken JSON: trailing commas and single quotes
BrowserStack’s JSON Formatter includes a Try auto-fix option for invalid JSON. It can help correct common syntax issues, such as missing commas or incorrect quotes, depending on the error.
- Trailing commas: Remove commas after the last property or array item.
- Single quotes: Replace single quotes with valid double quotes.
- Unquoted keys: Add double quotes around property names.
- Comments: Remove comments, which JSON does not support.
Review the repaired output before using it. Auto-fix may not resolve every error, especially when the JSON structure is incomplete or ambiguous.
Is it safe to format JSON online? Browser-only privacy
BrowserStack’s JSON Formatter processes and validates JSON directly in your browser. Your JSON is not uploaded to a server or stored externally during formatting and validation. You can beautify, minify, and inspect JSON without sending the payload to a remote service.
Even with browser-local processing, avoid exposing sensitive data unnecessarily. Redact API keys, access tokens, passwords, and customer information before sharing JSON in screenshots, support tickets, or public examples.
What is a JSON formatter?
A JSON formatter, also called a JSON beautifier or pretty printer, adds indentation and line breaks to compressed JSON so it is easier to read, inspect, and debug. It organizes nested objects and arrays into a clear structure without changing the underlying data.
JSON formatters commonly offer three functions:
- Beautify: Add indentation and line breaks to make JSON readable.
- Minify: Remove unnecessary whitespace to reduce the size of the JSON text.
- Validate and fix: Check JSON syntax, identify errors, and help correct common formatting issues.
JSON formatter vs. JSON validator
A formatter changes how JSON is presented. A validator checks whether the input follows JSON syntax rules, such as using double quotes around property names and string values.
For example, this compressed JSON is valid but difficult to scan:
{"user":{"name":"Aarav","role":"tester"},"active":true}A formatter turns it into a structured version:
{
"user": {
"name": "Aarav",
"role": "tester"
},
"active": true
}The data stays the same. The indentation simply makes the relationship between fields easier to follow.
BrowserStack’s free online JSON Formatter lets you beautify JSON, minify it, and fix syntax errors in one place. You can paste a JSON payload, inspect the formatted output, and correct invalid syntax before using the data in your application or debugging workflow.
Inspect and mock API responses after formatting with Requestly
After formatting an API response with BrowserStack’s JSON Formatter, use BrowserStack Requestly to inspect, mock, and modify HTTP requests and responses. You can change response data or simulate API scenarios to test how your application handles different values, errors, and edge cases without relying on the live API.
