name: OLTool version: '2.0' tags: - json - yaml - toml config: theme: dark indent: 2
About Data Format Converter
Development often means converting back and forth between JSON, YAML, TOML, XML and CSV: migrating config files, exporting API data, modeling tabular data. Previously you had to hop between many one-way tools. This tool brings them together — pick a source and target format, paste once, and convert in any direction, with one-click swap. All parsing and serialization happen locally in your browser; nothing is uploaded. Tip: Bookmark this tool for quick access whenever you need format conversion. All processing happens locally in your browser — no data upload, so feel free to paste sensitive content.
Use Cases
- Migrate config files — Turn YAML config into TOML or JSON to move seamlessly between toolchains.
- Export API data — Convert a JSON API response to CSV and import it straight into Excel or analytics tools.
- Cross-format comparison — View the same data as JSON or YAML to quickly understand structural differences.
- Tabular to structured — Convert a CSV table into a JSON array of objects for frontend rendering or API mocks.
- Integrate legacy XML — Turn XML into JSON for modern frontends, or generate XML payloads in reverse.
- Transform env files — Convert a flat .env key-value list into JSON or YAML for structured config injection in containers.
- Generate sample data — Write a quick CSV table in a spreadsheet, then convert to JSON objects for API mock endpoints.
FAQ
Which conversions are supported?
Any-direction conversion among JSON, YAML, TOML, XML and CSV, using a unified JS object as the intermediate representation.
Any requirements for CSV?
Exporting CSV requires an array of objects (one object per row); the tool uses the union of fields as headers. When importing CSV, the first row is treated as the header.
Do TOML/XML support complex structures?
Common tables, arrays, nesting and attributes are supported. For extremely complex TOML (e.g. nested inline tables) or namespaced XML, use the dedicated tool.
What does the swap button do?
It swaps the source/target formats and moves the current output into the input box, making round-trip conversion and verification easy.
Is my data uploaded?
No. All parsing and serialization run locally in your browser, so it is safe for configs or API data with sensitive fields.
Any browser compatibility requirements?
This tool works in all modern browsers (Chrome, Firefox, Edge, Safari). No plugins or extensions required.
Can I use it offline?
After initial load, most features work offline. The core logic runs entirely in your browser with no network dependency.