What YAML, TOML & JSON Converter helps you do

Configuration files arrive in three common shapes, and the tool you need usually accepts only one of them. Paste YAML, JSON, or TOML, choose the output format, and the document is parsed and rewritten locally with a clear error position when something is wrong. It is a converter and a syntax check in one step, which makes it useful before a deploy.

Parsing and serialization happen in your browser. Config files often contain credentials and internal hostnames, and none of that content leaves your device.

How it works

The input is parsed by a YAML, JSON or TOML parser into a data structure, then serialized in the chosen output format. The libraries run in the browser and report the position of a syntax error. YAML reads one document, and TOML output must start with an object, so shapes that the target format cannot express fail rather than silently changing.

How to use YAML, TOML & JSON Converter

Paste a config file, drop a .json, .yaml, or .toml file, or select Load example.
Leave the input format on Auto-detect, or pick JSON, YAML, or TOML explicitly.
Choose the output format, select Convert, then copy or download the result.
Fix the reported line if the parser rejects the input.

When to use it

Turn a Kubernetes or CI YAML file into JSON for an API or a script.
Convert a TOML config from a Rust or Python project into JSON.
Validate a config file and see exactly which line broke it.
Move a small config between tools that prefer different formats.
Inspect a YAML structure as JSON before writing a parser.
Check a TOML file before committing it to a repository.

When not to use it

Do not use it when comments must be preserved; the conversion drops them.
Do not convert a multi-document YAML file in one pass; split it first.
Do not use it for a very large file above the 5 MB cap.

Example

A Kubernetes deployment YAML is converted to JSON for a debugging script. The nested labels and container arrays appear as explicit objects and arrays, and the JSON is pasted into a request body. The original YAML stays in the repository because the JSON has lost its comments.

What you can do with YAML, TOML & JSON Converter

Convert any direction between JSON, YAML and TOML.
Auto-detect the input format or choose it explicitly.
Validate the input before converting.
Report the line and column of a parse error.
Copy the result or download it with the right extension.
Keep the config on your device.

Example: convert a CI YAML file to JSON

Paste the YAML and leave the input on Auto-detect. If the file starts with comments or a document marker, the converter still reads the first document.

Choose JSON and convert. Check the nested structure in the output; a mapping that was implicit in YAML becomes an explicit object in JSON.

Keep the original YAML if comments matter. The conversion goes through a data structure, so comments are not carried across.

What to know before you start

Comments are lost because the document is converted through a data structure.
Only a single YAML document is read; split multi-document files first.
TOML output requires an object at the top level and cannot represent null values.
Very large files are capped at 5 MB so the tab stays responsive.
Anchors and aliases are resolved into values rather than preserved.

Common mistakes

Expecting YAML comments to survive the JSON conversion.
Converting a multi-document YAML file and only getting the first document.
Writing TOML with a top-level array or a null value, which TOML cannot represent.
Assuming auto-detection is always right for a short or ambiguous file.
Losing indentation-sensitive YAML by editing it as plain text first.
Assuming YAML anchors and aliases are preserved rather than expanded.

Troubleshooting

If parsing fails, use the reported line and column; a tab in YAML or an unquoted colon is a common cause.

If only the first document appears, the file uses --- separators. Split it and convert each document.

If TOML output fails, the data contains a null, a top-level array, or an array of mixed types. Restructure it first.

If the output looks different from the input, check for implicit YAML types such as dates and booleans that become explicit values.

If the file is rejected for size, split the config or use a command-line tool.

YAML, TOML & JSON Converter