Documentation
How the tools parse configuration, what they refuse to invent, and what stays in the browser.
Where the work happens
Each tool parses text with JavaScript that ships to the browser. There is no upload endpoint and no server-side converter. The editor is loaded only when you open a tool. Explanatory text on each page is HTML, so you can read the limits before the editor starts.
YAML
YAML is read as YAML 1.2 with the core schema. true and false are booleans. yes, no, on, and off are strings. Duplicate keys are errors. A stream of more than one document is rejected by the converters because JSON and TOML hold one value. The Kubernetes YAML check reads each document and reports the document number. It does not check apiVersion, required fields, or unknown kinds. Merge keys written as << are not expanded. Comments cannot survive a conversion to JSON, and the YAML to JSON page says so when it sees them.
The validator does not format or repair the text. A successful result describes the top-level shape and leaves the editor alone.
JSON
JSON is parsed with the platform JSON parser. Trailing commas, comments, and single quotes are syntax errors. Pretty-printing uses two or four spaces and adds a trailing newline. Minify removes insignificant whitespace and does not add a newline. If an object repeats a key, the parser keeps the last value. Integers outside the safe range may already be imprecise; the formatter and the JSON to YAML tool report that instead of pretending the digits are exact. JSON Schema checks draft-07, or 2020-12 when $schema says so, and does not fetch a remote $ref. JSONPath returns a match list. A path that selects nothing is an empty list. Script filters are rejected.
TOML
TOML is parsed with smol-toml, which targets TOML 1.1. Tables become objects, arrays of tables become arrays, and booleans and strings stay themselves. Dates and times become JSON strings: offset datetimes keep their offset, local dates stay calendar dates, and local times stay clock times. inf and nan are rejected. Integers outside ±(2^53 − 1) are rejected. Comments are dropped. A # inside a quoted string is kept. Writing TOML rejects null and arrays whose items are not the same kind. The root value must be a table.
ENV
A .env file is a list of KEY=value lines. An optional export prefix is ignored. Every value stays a string, including digits and true or false. $NAME and ${NAME} are rejected and are not expanded. Duplicate keys are errors. The ENV validator reports those same failures and does not write JSON.
CSV
CSV is read as comma-separated fields. A comma or line break inside quotes stays in the field. An unclosed quote is an error and no JSON is written. With a header row, duplicate headers are errors. JSON to CSV accepts an array of objects with the same keys, or an array of arrays. Nested objects and arrays are rejected. Numbers and booleans are written as text, and null becomes an empty field.
Guides
Keyboard
With focus inside a tool, Ctrl+Enter or ⌘+Enter runs it immediately. Copy and download are buttons, so they are available from the keyboard without taking over the system copy shortcut.