Data Format Converter

JSON → CSV: Input must be an array of objects. Headers are the keys of the first object; nested values are serialized as JSON strings. Fields containing commas or quotes are automatically quoted.
CSV → JSON: The first row is treated as column headers. Produces an array of objects with string values.
JSON → YAML: Any valid JSON is converted to its YAML equivalent.

All processing happens in your browser, no data leaves your device.

JSON (JavaScript Object Notation) was formalised by Douglas Crockford in the early 2000s as a lightweight alternative to XML. Despite the name it is language-agnostic and has become the dominant data interchange format for web APIs. It supports six types: strings, numbers, booleans, null, arrays, and objects. Its main strengths are human readability and near-universal library support; its main limitation is no support for comments.

CSV (Comma-Separated Values) is one of the oldest data formats still in active use, with roots in the early 1970s mainframe era. Each row is a record, each field is separated by a comma (or sometimes a tab or semicolon). It has no official standard, RFC 4180 (2005) documents common practice rather than mandating it, which is why edge cases like embedded commas, quotes, and newlines are handled inconsistently across tools. Its enduring appeal is extreme simplicity: any spreadsheet application can open it.

YAML (YAML Ain't Markup Language) was designed in 2001 as a human-friendly serialisation format, leaning on indentation rather than brackets or tags. It is a superset of JSON (any valid JSON is valid YAML), but its own syntax is terser and easier to write by hand. It is the format of choice for configuration files (Docker Compose, GitHub Actions, Kubernetes, Ansible) because it is readable without tooling. The tradeoff is that indentation-sensitivity makes it easy to introduce subtle bugs, and its extensive feature set (anchors, aliases, multiple document types) can surprise users who expect simplicity.