Multi-Format Data Converter (JSON ↔ YAML ↔ CSV)
Convert configuration files and structured payloads between JSON, YAML, and CSV 100% client-side with zero data transmission.
Packages & Libraries: Powered by zero-telemetry client-side format parsers (JSON, YAML, CSV) executing locally in ECMAScript.
⚖️ Legal Notice: This data conversion utility is provided "as is", without warranty of any kind, express or implied. All data format transformations occur 100% locally inside your browser; zero payload strings are uploaded to remote servers.
What this tool does
It converts structured data between JSON, YAML, and CSV in your browser: pick a source and target format, paste your data, and parsers written for this page — plain JavaScript, no libraries — do the round trip. The CSV reader handles quoted fields and escaped quotes, treats the first row as a header, and types values that look like numbers or booleans. The YAML reader covers the indentation-based core of the language: nested maps, lists, quoted strings, and comments. The emitters produce clean YAML (with conservative quoting of ambiguous scalars) and CSV with proper escaping. A sample for each format is one click away.
How to use it
- Choose source and target formats — the conversion re-runs automatically when you change either.
- Paste your data, or load a sample to see the shape it expects.
- Press Transform Data Format and copy the result from the right pane. Errors appear inline instead of as a silent empty output.
Where your data goes
Nowhere. There are no libraries and no network calls — the parsers are plain functions embedded in the page, so your configuration, including any secrets inside it, never leaves the tab. Nothing is stored; reload clears both panes. That is the reason this converter exists: pasting a config file with credentials in it into a random server-side converter is a habit worth breaking.
Who it's for
Developers doing one-off config surgery — a compose file into JSON for an API call, a CSV export into YAML, a JSON payload into CSV for a spreadsheet. Also anyone testing "is this YAML valid in the way I think it is" before a pipeline eats it. For repeated production conversions, use a real library in your own toolchain; this is the no-install, no-upload scratchpad.
Honest limits
- No TOML. The selectors convert JSON, YAML, and CSV — that is the full list; no TOML parser is wired into this page. For TOML, use a dedicated parser in your own toolchain.
- The YAML reader is a subset. Anchors and aliases, block scalars (
|and>), flow collections, and tags are not supported. Common config files parse fine; exotic YAML will not round-trip faithfully. - CSV wants a header row and flat, uniform records. Nested objects serialize as JSON strings inside cells; ragged rows keep whatever columns they have.
- CSV values are auto-typed: a cell reading
truebecomes a boolean and3.14becomes a number — leading-zero strings and phone numbers may surprise you.
Questions people ask
What happens to duplicate keys or ragged rows?
JSON objects keep the last occurrence of a duplicate key (standard parser behavior). CSV output takes the union of all keys present in the input records; a record missing a column exports an empty cell there. The converter surfaces what you gave it — it does not reconcile it.
Why did my number come out as a string?
Scalars only become numbers when the source format says so — a YAML 8080 is a number, "8080" is a string. The converter never guesses beyond what the source text encodes, which is the behavior you want in a tool you might paste credentials into.
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