What is JSON Formatter & Validator?
The JSON Formatter & Validator is a free online tool that takes raw or minified JSON data and transforms it into a cleanly indented, human-readable format while simultaneously checking for syntax errors. JSON (JavaScript Object Notation) is the most widely used data-interchange format on the web, powering REST APIs, configuration files, NoSQL databases, and more. Because JSON is strict about syntax — a single misplaced comma or missing bracket will break an entire payload — having a reliable formatter and validator at hand saves developers significant debugging time. This tool parses your input against the official JSON specification (RFC 8259), highlights errors with precise line and column numbers, and outputs perfectly indented JSON that is easy to read, share, and commit to version control.
Why Use JSON Formatter & Validator?
Working with raw API responses, log files, or database exports often means dealing with dense, single-line JSON that is nearly impossible to scan by eye. Manually adding indentation is tedious and error-prone. Our JSON Formatter instantly beautifies the data and validates it in one step, so you can spot missing keys, incorrect nesting, or type mismatches at a glance. It is especially valuable during API development when you need to inspect response bodies, during code reviews where configuration files must be readable, and when collaborating with teammates who use different editor settings. Unlike browser-extension formatters, this tool works with any JSON payload size and does not require installation.
How to Use
Paste your raw JSON into the input editor or upload a .json file. The tool automatically detects and reports syntax errors as you type, underlining the exact position of each issue. Click the Format button to pretty-print the JSON with your preferred indentation (2 spaces, 4 spaces, or tabs). You can also collapse and expand individual nodes in the tree view to focus on the section you care about. Once satisfied, copy the formatted output to your clipboard or download it as a new file. For quick sharing, use the generated permalink that encodes the JSON in the URL.
Example Usage
Suppose you receive the following minified API response: {"users":[{"id":1,"name":"Alice","roles":["admin","editor"]},{"id":2,"name":"Bob","roles":["viewer"]}]}. Pasting it into the formatter produces a neatly indented structure where each key-value pair sits on its own line, arrays are clearly delineated, and you can instantly verify that both user objects have the expected fields. If someone accidentally leaves a trailing comma — {"id":1,"name":"Alice",} — the validator highlights the comma and explains that trailing commas are not permitted in standard JSON.
Benefits
Instant syntax validation saves hours of debugging malformed payloads. Configurable indentation ensures consistency across teams. The tree view lets you navigate deeply nested structures without losing context. Copy-to-clipboard and download options streamline your workflow. The tool runs entirely in your browser, so sensitive data is never sent to a server.