Free JSON to YAML Converter (and YAML to JSON, Bidirectional)
Paste JSON and get clean indented YAML, or paste YAML (Kubernetes, GitHub Actions, Docker Compose) and get parsed JSON. Swap direction with one click. Inline error messages. 100% client-side — configs never leave the browser.
name: Toolk
version: 1.0.0
tools: 65
free: true
features:
- ad-free
- fast
- private
config:
port: 3000
ssl: true
limits:
requestsPerMinute: 60
uploadMb: nullThis converter implements the most common subset of YAML 1.2 block style — mappings, sequences, scalars, comments, and nesting. Advanced features (anchors, aliases, multi-line block scalars, flow style mixed with block style) may not round-trip perfectly. For complex YAML, double-check your output before deploying.
Bidirectional
JSON → YAML with proper block-style indentation and string quoting. YAML → JSON with a focused YAML-subset parser tuned for real-world config files.
Inline Error Reporting
Malformed input shows a line-numbered error message — no silent failures. Spot the missing colon or unbalanced brace immediately.
One-Click Copy + Sample Loaders
Copy converted output to clipboard. Load sample JSON or YAML to see exactly what the converter produces from typical config patterns.
100% Client-Side
No uploads, no API calls, no tracking. Configs may contain secrets — they stay in your browser. Works offline once loaded.
Translate Between the Two Languages of Configuration
JSON dominates API payloads; YAML dominates infrastructure-as-code. The practical reality of 2026 backend work means you switch between them several times a day — copying a Kubernetes secret value into a CI script that only accepts JSON, or turning a JSON API spec into a more reviewable YAML for a pull request. Our Free JSON to YAML Converter handles both directions with a custom serializer (JSON → YAML) that emits clean block-style output and a focused YAML 1.2 subset parser (YAML → JSON) tuned for the real-world configs you actually deal with: Kubernetes manifests, GitHub Actions workflows, Docker Compose files, Ansible playbooks. Everything runs in your browser, so secrets and internal config never leave the page.
Pair this with our JSON Formatter (beautify and validate JSON), YAML Validator (validate YAML syntax with line-precise errors), JSON to TypeScript (generate interfaces from the JSON side), and the CSV to JSON Converter (the third common tabular ↔ structured format pair).
JSON vs YAML — Eight Differences That Matter
| Aspect | JSON | YAML |
|---|---|---|
| Quoting | All strings quoted with double quotes | Strings usually unquoted; quote only when ambiguous |
| Comments | No comments allowed (use JSONC or JSON5 extensions) | Hash-prefixed (# comment) |
| Multi-line strings | Single-line only with \n escapes | Block scalars (| literal, > folded), single-line as default |
| Structure delimiters | Braces { } and brackets [ ] (explicit) | Indentation (whitespace-significant) |
| Trailing commas | Forbidden (strict JSON); allowed in JSON5 | Not applicable — no commas in block style |
| Booleans / null | true, false, null (lowercase only) | true/True/TRUE, false/False/FALSE, null/~/empty |
| Best for | APIs, machine-to-machine, configuration with strict schema | Human-edited configs (Kubernetes, GitHub Actions, Docker Compose) |
| File extensions | .json, .jsonc, .json5 | .yml, .yaml |
Where Each Format Is the Standard
| Context | Format | Notes |
|---|---|---|
| Kubernetes manifests | YAML required | apiVersion, kind, metadata, spec — all standard k8s files. |
| GitHub Actions workflows | YAML required | .github/workflows/*.yml — name, on, jobs, steps. |
| Docker Compose | YAML required | compose.yaml or docker-compose.yml — services, volumes, networks. |
| CI configs (CircleCI, Travis) | YAML required | Build pipelines historically standardized on YAML for human edit. |
| Ansible playbooks | YAML required | *.yml — tasks, hosts, vars, handlers. |
| REST API responses | JSON required | All major HTTP frameworks emit JSON by default. |
| package.json / tsconfig.json | JSON required | Node.js ecosystem manifests. |
| OpenAPI specs | Either | OpenAPI accepts both — YAML for human edit, JSON for tooling. |
Gotchas When Round-Tripping JSON ↔ YAML
1. Comments Are Lost
JSON has no comment syntax. YAML → JSON → YAML loses every # comment. If your YAML has important context in comments, do not round-trip it.
2. The Norway Problem
YAML 1.1 treated NO, YES, ON, OFF as booleans — so country code NO became false. YAML 1.2 fixed this; our parser follows 1.2. Still, quote ambiguous strings: country: "NO".
3. Numeric Precision
JavaScript numbers max out at 2^53. Very large integers (timestamps in nanoseconds, big DB IDs) round to nearest float. Quote them as strings to preserve precision.
4. Indentation Sensitivity
YAML uses 2-space indentation in practice. Tabs are ambiguous. If you mix tabs and spaces, the parser may fail with cryptic errors — convert tabs to spaces before parsing.