What It Does

Paste a config in one format, get it back in another. It handles the four formats that cover almost all real-world configuration:

JSON - the lingua franca
YAML - Kubernetes, CI pipelines, most modern app config
TOML - Rust/Cargo, Python (pyproject), many Go tools
.env - local development and twelve-factor apps

Pick a target format tab and the conversion happens live as you type. Leave the source on “Auto-detect” and it figures out what you pasted.

It Runs Entirely In Your Browser

The parsers and serializers are hand-written with zero dependencies - there is no server, no upload, and no network call at any point. That matters because config files routinely contain secrets: database URLs, API keys, tokens. Anything you paste stays in the tab. You can disconnect from the internet and it still works.

How It Works

Every format is parsed into a single plain-JavaScript intermediate value, then serialized out to the target. That shared representation is what makes any-to-any conversion clean: JSON→TOML and YAML→.env go through exactly the same middle step. The .env target is flat by nature, so nested keys are flattened to PARENT_CHILD form and arrays or objects are emitted as JSON strings.

Pairs well with the JSON Formatter for cleaning up the JSON side and CSV to JSON when your data starts as a spreadsheet.

Limitations

It targets the common-config subset of each format - the shapes real config files actually use. It does not implement:

YAML anchors/aliases, multi-document streams (---), or block scalars (| / >)
TOML some dotted-key and deeply-nested array-of-tables edge cases
Comments are stripped on conversion (they have no home in the target structure)

When the input uses something outside the subset, you get a clear parse error rather than a silently wrong result. For anything exotic, treat the output as a strong first draft and eyeball it.