YAML to JSON Converter

How to convert YAML to JSON

1. Paste YAML into the left box, drop a .yaml or .yml file on it, or press Upload.
2. Valid YAML is converted as you type. If there is a mistake, the status line names it and gives the line and column; Show in input jumps there.
3. Pick the JSON indentation (2 spaces, 4 spaces, tabs or minified), then Copy or Download .json.

YAML to JSON example

A Docker Compose style file with a comment, an anchor (&base) and merge keys (<<: *base):

# shared settings
x-base: &base
  restart: always
  environment:
    TZ: UTC

services:
  web:
    <<: *base
    image: nginx:1.27
    ports: ["8080:80"]
  worker:
    <<: *base
    image: shop/worker:3
    replicas: 2

converts to the JSON below. The comment is gone, and each service gets its own full copy of the shared settings:

{
  "x-base": {
    "restart": "always",
    "environment": {
      "TZ": "UTC"
    }
  },
  "services": {
    "web": {
      "restart": "always",
      "environment": {
        "TZ": "UTC"
      },
      "image": "nginx:1.27",
      "ports": [
        "8080:80"
      ]
    },
    "worker": {
      "restart": "always",
      "environment": {
        "TZ": "UTC"
      },
      "image": "shop/worker:3",
      "replicas": 2
    }
  }
}

The x-base block itself stays in the output because it's an ordinary key. To explore a long result, open it in the JSON viewer.

Fixing YAML errors

Most YAML errors are about indentation. Here, port has three spaces instead of two:

server:
  host: example.com
   port: 8080

The converter stops with: Invalid YAML: bad indentation of a mapping entry (line 3, column 8). Other common ones:

• Tabs: a tab used for indentation gives "tab characters must not be used in indentation" (line 2). YAML only allows spaces.
• Duplicate keys: writing name: twice in one mapping gives "duplicated mapping key" (line 2). JSON parsers would silently keep the last one; YAML treats it as an error.
• Unquoted colons: a value like title: Note: read me needs quotes: title: "Note: read me".

Multi-document YAML to JSON

Kubernetes manifests often hold several documents separated by ---. They become a JSON array, one item per document:

---
kind: Service
metadata: { name: web }
---
kind: Deployment
metadata: { name: web }

[{"kind":"Service","metadata":{"name":"web"}},{"kind":"Deployment","metadata":{"name":"web"}}]

How YAML types become JSON

The converter uses the YAML 1.2 core schema, the current standard, so only unambiguous values change type:

enabled: yes
debug: false
version: 1.10
released: 2026-09-25
port: 8080
owner: ~

{
  "enabled": "yes",
  "debug": false,
  "version": 1.1,
  "released": "2026-09-25",
  "port": 8080,
  "owner": null
}

• yes stays a string: in YAML 1.2 only true/false are booleans.
• 1.10 is a number, so it becomes 1.1. Quote version numbers in YAML ("1.10") to keep them exact.
• Dates stay strings, because JSON has no date type. ~ and null become null.
• .inf and .nan have no JSON form and become null, with a warning.

What is not kept

Comments, anchor names, quoting style and blank lines are YAML presentation, and JSON has no place for them. Key order and all values are kept. Converting back with the JSON to YAML converter gives clean, equivalent YAML, but without the comments. To tidy or check the JSON itself, format and validate the JSON.

On the command line, yq -o json file.yaml or python -c 'import sys, json, yaml; json.dump(yaml.safe_load(sys.stdin), sys.stdout, indent=2)' < file.yaml do the same job (PyYAML follows YAML 1.1, so yes becomes true there).

Frequently asked questions