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How to Convert YAML to JSON: Python, Node, yq, and Online (Without Uploading Secrets)

Convert YAML to JSON with Python's yaml.safe_load, Node's js-yaml, or yq -o=json — plus what gets lost in the trip (comments, anchors, yes/no coercion) and how to convert in your browser without uploading secrets.

October 15, 2026 · 6 min read · Shayan

Short answer: parse the YAML and dump it as JSON. In Python that is yaml.safe_load followed by json.dumps; in Node it is js-yaml's load plus JSON.stringify; on the command line it is yq -o=json. For a one-off conversion, paste the YAML into an in-browser converter — nothing leaves your device, which matters when the file holds API keys or database passwords. The conversion itself is mechanical; the surprises are in what YAML allows and JSON does not: comments, anchors, multi-document files, and plain values like yes that silently become booleans.

Pick your method

  • Python — you already have it and PyYAML installed: yaml.safe_load + json.dumps. Best for scripts and CI pipelines.
  • Node — js-yaml is the standard: yaml.load + JSON.stringify. Best when the project is already JavaScript.
  • yq — the jq of YAML: yq -o=json file.yaml. Best for shell pipelines and Kubernetes manifests.
  • Online converter — paste and convert in the browser. Best for one-offs, especially when the file contains secrets.
  • PowerShell — has no built-in YAML cmdlet, so do not plan around one: install yq via winget or use Python.

Python

import yaml, json

with open("config.yaml") as f:
    data = yaml.safe_load(f)  # never yaml.load without a Loader — safe_load blocks arbitrary code execution

print(json.dumps(data, indent=2))

Use safe_load, not load. Plain yaml.load can construct arbitrary Python objects from a malicious file — safe_load only builds plain dicts, lists, strings, and numbers. If a teammate's config.yaml came from the internet, this one-word difference is a real security boundary.

Node.js

import yaml from "js-yaml";
import { readFileSync } from "node:fs";

const data = yaml.load(readFileSync("config.yaml", "utf8"));
console.log(JSON.stringify(data, null, 2));

yq on the command line

# one file to stdout
yq -o=json config.yaml

# one file to disk
yq -o=json config.yaml > config.json

# every manifest in a directory (the Kubernetes habit)
for f in manifests/*.yaml; do
  yq -o=json "$f" > "${f%.yaml}.json"
done

What gets lost in conversion

JSON is a smaller language than YAML, so some things cannot survive the trip. Nothing errors — they just quietly disappear or change shape:

  • Comments — JSON has no comments, so every # note is dropped silently.
  • Anchors and aliases (&base / *base) — they are resolved and duplicated into plain repeated values in the JSON output.
  • Multi-document files (--- separators) — JSON has a single root. Most tools emit one JSON object per document or take the first; check before you trust the output.
  • Date and bool coercion — YAML 1.1 treats yes, no, on, and off as booleans, and unquoted 2026-10-15 as a date. If a value must stay a string, quote it in the YAML before converting.

The two errors everyone hits

# PyYAML
found character '\t' that cannot start any token

# js-yaml
bad indentation of a mapping entry

YAML forbids tabs for indentation — both of these errors mean a tab slipped in. Replace tabs with spaces (2 is the convention) and the parse succeeds. The other classic is the yes-becomes-true coercion above: a config value of on: yes arrives in your JSON as true, and your string comparison silently fails. Quote it: on: "yes".

Quick answers

  • Can I convert without installing anything? Yes — paste the YAML into an in-browser converter. The parsing happens in your tab, so nothing is uploaded; that is the whole point when the file contains secrets.
  • Is it safe to paste a kubeconfig into an online converter? Only if it runs entirely in your browser with no upload. Never paste secrets into a server-side converter — assume anything you send is logged.
  • What about JSON to YAML? The reverse is safe and lossless for data: yq -o=yaml file.json, or yaml.dump(JSON.parse(text)) in Node with js-yaml.
  • Why did my on: yes become true? YAML 1.1 boolean coercion: yes, no, on, and off are booleans in PyYAML and js-yaml's default schema. Quote the value to keep it a string.
  • Do I need yq or will jq work? jq reads JSON, not YAML. Pipe them together — yq -o=json file.yaml | jq '.spec.replicas' — when you want jq's querying on YAML input.

Try it

Paste the YAML into the JSON / YAML / CSV Converter — it converts entirely in your browser, so configs with secrets never leave your device. If the JSON it produces looks wrong, How to Format JSON in JavaScript shows how to validate and pretty-print it.

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