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Convert JSON
Convert JSON to and from YAML, TOML, CSV, XML, NDJSON, query strings, .env, MessagePack, CBOR, and BSON — numbers keep their exact value, and every mapping rule and loss is shown before and after the conversion.
Every conversion runs through one shared model: JSON → YAML. The rules below always apply — nothing converts until you have seen them.
Strict JSON (RFC 8259)
Nothing in yet
Paste, drop, or type to begin. Everything stays on this device.
How JSON → YAML maps
Reading JSON
- Strict JSON (RFC 8259) by default; the JSONC option also accepts comments and trailing commas and reports both as dropped.
- Numbers keep their exact spelling — 1e400, 30-digit integers, 1.50, -0 travel to the target format verbatim.
- Duplicate object keys: the LAST value wins and every duplicate is reported (first position keeps its place).
Writing YAML
- 2-space block style, 100-column line width; strings that look like numbers or booleans are quoted so they cannot re-parse as something else.
- Numbers emit their exact lexeme; object key order follows the source.
- Dates (arriving from TOML) become plain ISO strings — YAML core has no date type.
- Binary payloads (arriving from MessagePack/CBOR/BSON) become lowercase hex strings; MessagePack extensions keep their payload hex; CBOR tags keep their inner value — each with a loss note.
JSON capabilities
- comments: no
- duplicateKeys: yes
- bigIntegers: yes
- dates: no
- binary: no
- orderedMappings: yes