JSON to YAML Converter

How to use

1. Paste JSON into the input pane. Conversion starts in the JSON → YAML direction (shown in the badge), and the output pane fills in as you type — no button press needed.
2. Choose 2 or 4 spaces from the Indentation dropdown. Two is the default and the width nearly every YAML ecosystem expects.
3. Hit Swap to flip to YAML → JSON. Whatever sits in the output pane carries back into the input, so you can convert, edit, and send it the other way without retyping.
4. In the YAML → JSON direction, tick Minify JSON output to collapse the result onto one line; the indentation setting is ignored while minify is on.
5. Copy the output, or Download it as converted.yaml or converted.json. Sample loads an example to poke at, and Clear empties both panes.

How it works

The converter never does a text find-and-replace between the two formats. It parses your input into a real in-memory value, then re-serialises that value into the target format. Going JSON → YAML, JSON.parse turns the text into a JavaScript object and the js-yaml library’s dump writes it out as YAML at your chosen indent (with lineWidth: -1, so a long URL or token stays on a single line instead of folding). Going the other way, js-yaml’s load reads the YAML into a value and JSON.stringify prints it — indented to match your setting, or as one compact line when Minify is ticked.

A short example. This JSON:

{"queue":"emails","workers":4,"durable":true,"routes":["signup","reset"],"limits":{"rate":100,"burst":150}}

converts, at 2-space indent, to:

queue: emails
workers: 4
durable: true
routes:
  - signup
  - reset
limits:
  rate: 100
  burst: 150

Each array element becomes a - line indented beneath its key, and the nested limits object becomes its own indented block. Because the pipeline runs through an actual value rather than your keystrokes, it is the structure that survives the trip, not the exact spacing you typed.

Use cases & limitations

Open this when an API hands you JSON but the file you are editing — a Kubernetes manifest, a GitHub Actions workflow, a Docker Compose service — wants YAML, or when you need the reverse. It doubles as a quick validity check: if either side refuses to parse, the input has a syntax error worth catching before you commit it. When you only need to tidy or verify JSON, the JSON formatter is the better fit, and the JSON to CSV converter handles the case where the destination is a spreadsheet rather than a config file.

The main limitation is schema coverage. js-yaml reads the default YAML schema, so custom tags — CloudFormation’s !Ref and !GetAtt, or !!python/... types — are not recognised, and the parse stops with an unknown-tag error. Anchors and aliases (&anchor / *anchor) are resolved as the document loads, which means the JSON output repeats the shared value inline instead of preserving the reference. For plain configuration data neither matters; for a hand-authored template that leans on those features, it will.

Privacy note

Both directions run inside your tab: js-yaml plus the browser’s own JSON.parse and JSON.stringify, with no server in the loop. The library is fetched once from this site’s own files the first time you convert, and it carries none of your document with it; from then on, typing, swapping, copying, and downloading reach no network at all. Configuration files routinely hold secrets — API keys, database URLs, access tokens — so it matters that nothing you paste here is transmitted, logged, or kept.