Config Converter

How to use it

1. Paste your config — YAML, JSON or Java .properties. The format is detected and the other two appear below as you type; there is no button to press.
2. If the guess is wrong, pick the source format yourself. Choose 2 or 4 spaces of indentation, and turn “Expand dotted keys” off to keep Spring-style keys flat.
3. Copy or download each result on its own — the file names are config.yaml, config.json and config.properties.

Example

server:
  port: 8080
  name: order-service
debug: true

{
  "server": {
    "port": 8080,
    "name": "order-service"
  },
  "debug": true
}

Properties
----------
server.port = 8080
server.name = order-service
debug = true

Default rules only: the source is detected as YAML, so 8080 stays a number and true stays a boolean. Properties has no types, so the same values come out as the strings 8080 and true — when the source is .properties they are strings all the way through.

Rules, limits and known issues

• Only three formats: YAML, JSON and Java .properties. No TOML, no INI [section] headers, no XML or CSV.
• YAML is supported as a config subset: block mappings, sequences, flow {…} / […], quoted scalars and | / > block scalars. Anchors (&), aliases (*), !tags, << merge keys and ? complex keys are reported as errors instead of being guessed.
• Only the first YAML document is converted; a later --- is ignored and reported.
• Comments are not carried over: the three formats place them differently, so a comment kept in the wrong place is worse than no comment.
• Properties has no types. Every value is a string, so port = 8080 becomes "8080" in JSON — not 8080. Numbers, booleans and nulls only survive when the source is YAML or JSON.
• Non-ASCII text is written as-is (UTF-8), not escaped as \uXXXX. Java’s Properties.store() writes ISO-8859-1, so save the file as UTF-8 if you paste it into a Java project.
• Integers beyond the safe range (such as 12345678901234567890) are kept as strings with the exact digits you typed, instead of being rounded to a number.
• Key order follows your input; there is no sorting option.
• A top-level array or bare value cannot be written as properties — that one panel reports it, the other still converts.
• No file upload, no URL parameters, no history. Everything runs in your browser: nothing is uploaded or stored.
• A string containing a line break is written as "a\nb" in YAML, not as a | block scalar.
• Limits: 1,000,000 characters and 64 levels of nesting — over either, you get an error instead of a truncated result. Above 200,000 characters the result updates about 0.6 s after you stop typing; output uses LF and has no trailing newline.

Related tools

What people usually need next, once the config is in the right format.