Data Converter
Convert between JSON, CSV, YAML and TOML data formats. Paste or upload. Free, browser-based.
Input
Output
JSON Input
CSV Output
About Data Converter
Modern software development involves constantly moving data between different systems, each with its own preferred format. REST APIs return JSON, configuration files often use YAML or TOML, spreadsheets work with CSV, and analytics pipelines might need flat table structures. Converting between these formats manually is tedious and error-prone — one missed comma or incorrect indentation can invalidate an entire file.
Our Data Converter handles bidirectional transformation between JSON, CSV, YAML, and TOML formats with validation at every step. The converter detects syntax errors in your input before transforming it, highlighting exactly where the problem is so you can fix it before proceeding. Nested JSON objects convert to flattened CSV using dot notation (e.g., a `user.name` key becomes a "user.name" column header), making complex API responses accessible in spreadsheet tools.
You can paste data directly into the input field or upload a file. The output can be copied to your clipboard or downloaded as a new file. Everything runs locally in your browser — your configuration files, API keys, and structured data stay completely on your device.
How to Use Data Converter
- 1Paste your source data into the input field, or click "Upload File" to load a JSON, CSV, YAML, or TOML file.
- 2The tool auto-detects the input format, or you can select it manually from the dropdown.
- 3Select the target output format from the "Convert To" dropdown.
- 4Click "Convert" — any syntax errors in the input will be highlighted before conversion.
- 5Copy the output to clipboard or click "Download" to save the converted file.
Use Cases
- →Convert a JSON API response to CSV for analysis in Excel or Google Sheets
- →Transform a YAML configuration file to JSON for use in a JavaScript application
- →Convert TOML config files to YAML for compatibility with deployment pipelines
- →Flatten a nested JSON structure to a CSV for database import or reporting
- →Convert CSV data exports from a CRM or analytics tool to JSON for API consumption
- →Reformat configuration files when migrating between tools that use different formats
Tips
- ✓The converter validates your input before transforming — syntax errors are shown with line references
- ✓Arrays of objects convert to CSV rows with the object keys becoming column headers
- ✓Nested JSON objects are flattened with dot notation (e.g., user.address.city) in CSV mode
- ✓YAML is the most human-readable format — great for configuration files read and edited manually
- ✓TOML is commonly used in Rust (Cargo.toml), Hugo, and Rust-based frameworks
- ✓For very large files (several MB), processing may take a few seconds entirely in your browser
Frequently Asked Questions
JSON (JavaScript Object Notation), CSV (Comma-Separated Values), YAML (YAML Ain't Markup Language) and TOML (Tom's Obvious, Minimal Language). All conversions are bidirectional — any format can be the input or output.
The JSON input must be an array of objects. Each object becomes a CSV row, with the object keys becoming column headers. If objects have different keys, missing values are left empty. Nested objects are not supported for CSV output.
Yes. Click the "Upload file" button above the input panel to load a .json, .csv, .yaml, .yml or .toml file directly from your computer. The file is read in your browser — it is never sent to a server.
TOML is a configuration file format designed to be easy for humans to read and write. It's commonly used for configuration files in Go, Rust and other languages (e.g., Cargo.toml).
Both YAML and JSON can represent the same data structures. YAML uses indentation instead of brackets and is more human-readable. JSON is stricter, requires quotes around strings and is more widely supported in programming environments.
The Swap button reverses the input and output format selection and moves the current output text into the input panel. This lets you quickly do a round-trip conversion or continue working with the converted output.