YAML / TOML Converter
Round-trip between YAML, JSON and TOML. Paste any format, convert to either of the others instantly.
Round-trip between YAML, JSON and TOML. Paste any format, convert to either of the others instantly.
This free YAML / TOML Converter from KX Toolkit is part of our all-in-one online toolkit. It runs entirely in your browser, so your data never leaves your device for client-side operations. 100% free, forever - no paywall, no credit card, no trial.
How to use the YAML / TOML Converter
- Paste your input - JSON, regex pattern, JWT, URL etc.
- Pick any flags or options the tool supports.
- Click the action button (Format, Test, Decode).
- Copy the result or download it as a file.
What you can do with the YAML / TOML Converter
- Format and validate API responses while debugging.
- Test regex patterns against real input before deploying.
- Decode JWTs to inspect claims and expiry.
- Generate UUIDs for migrations, tests and seeders.
Why use KX Toolkit's YAML / TOML Converter
- Browser-based: Works on Windows, macOS, Linux, iOS and Android - no install, no extension.
- Privacy-first: Client-side tools never upload your data; server-side tools delete files right after processing.
- Mobile-friendly: Full feature parity on phones and tablets - not a stripped-down view.
- Fast: Optimised for instant feedback. No artificial waiting screens, no email-gated downloads.
- One hub for everything: 300+ tools across SEO, text, image, PDF, code, color, calculators and more - skip switching between sites.
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When would I convert between YAML, JSON, and TOML?
YAML is common in DevOps configs (Kubernetes, GitHub Actions), JSON is the lingua franca for APIs and front-end tools, and TOML powers Rust's Cargo, Python's pyproject, and many static-site generators. Round-tripping is useful when migrating projects, checking that a config is valid in two formats, or generating one from a more comfortable source.
Does conversion preserve comments?
Mostly no. JSON has no comment syntax, so comments are dropped when going through it. TOML preserves comments only if the parser keeps them as metadata. YAML allows comments natively but converters frequently treat them as whitespace. If comments matter, convert at the structural level only and re-add explanations afterward, or stick to YAML round-trips.
What are the gotchas of YAML's implicit typing?
YAML interprets unquoted strings as booleans, numbers, dates, or null when they match certain patterns. The notorious example is the country code NO being parsed as boolean false in YAML 1.1. Convert to JSON or TOML and the value becomes the bool false. Quote any value that should remain a string, especially version numbers, country codes, and IDs.
How does TOML differ from JSON for nested structures?
TOML uses table headers in square brackets and dotted keys instead of nested objects with braces. It is great for flat-ish configs with a few levels of nesting but awkward for deeply nested or array-heavy data. The converter renders deep JSON as inline tables which can become unreadable; for those cases JSON or YAML usually fits better.
Why does the converted output sometimes reorder keys?
Some parsers store data in unordered maps and the serializer emits keys alphabetically or in insertion order depending on implementation. JSON does not care about order semantically, but TOML and YAML do for human readability. If diffability matters, sort keys consistently before and after conversion or use a converter that preserves order.
Can the tool validate the input as well as convert it?
Yes - to convert at all the parser must validate first. Errors include indentation problems in YAML, trailing commas in JSON (forbidden in standard JSON), and duplicate keys in TOML. The error message points to the line and column. Fix the source until it parses cleanly, then conversion succeeds in any direction the data fits.
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