Free Online JSON Tools
Format, validate, convert, and transform JSON data in your browser. All tools are free, private, and require no sign-up.
JSON Formatter & Validator
Format, validate, beautify, and minify JSON online. Collapsible tree view, error detection with line numbers. Free, fast, runs entirely in your browser — no data sent anywhere.
JSON to CSV Converter
Convert JSON arrays to CSV format. Download as .csv file or copy to clipboard. Handles nested objects and special characters. Free, browser-based.
JSON to YAML / YAML to JSON
Convert between JSON and YAML formats instantly. Supports nested objects, arrays, and all data types. Free, browser-based.
CSV to JSON Converter
Convert CSV data to JSON format online. Auto-detects delimiters, supports headers and quoted fields. Free, browser-based.
What is JSON?
JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It is the most widely used format for APIs, configuration files, and data storage on the web. JSON supports strings, numbers, booleans, null, arrays, and objects.
Common JSON tasks for developers
Formatting and validating API responses is the most frequent use case. When debugging a REST API, the response is often minified JSON that is difficult to read. The JSON Formatter adds proper indentation and validates the structure, showing errors with line numbers.
Converting between formats is another daily task. Exporting data from an API to a spreadsheet requires JSON to CSV conversion. Importing spreadsheet data into a web application needs the reverse: CSV to JSON. DevOps engineers frequently convert between JSON and YAML for configuration files using the JSON to YAML converter.
Why use browser-based JSON tools?
When you paste an API response into an online JSON formatter, that data hits someone else's server. If the response contains customer data, authentication tokens, or internal API structures, you are exposing it. All DevToolbox JSON tools process data entirely in your browser. Nothing is transmitted. This makes them safe for production data, internal APIs, and sensitive payloads.