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| and >), quoted/plain scalars
and comments. Anchors/aliases (&, *), multi-document files and complex
keys are out of scope and will raise a clear error.
YAML is the human-friendly configuration language behind Docker Compose files, CI pipelines, Kubernetes manifests, and countless app configs. JSON is the machine-friendly format that APIs, JavaScript, and most tooling actually consume. Our free YAML to JSON Converter translates between the two instantly: paste YAML, get valid JSON — with nothing ever leaving your browser.
The converter uses a purpose-built YAML parser that runs entirely client-side, with no libraries to download and no server round-trip. It handles the constructs that make up the vast majority of real-world YAML: key-value mappings, sequences (lists), nested indentation, block scalars using both the literal | style (newlines preserved) and the folded > style (newlines folded), quoted and plain scalars, comments starting with #, and automatic typing — the strings "true", "false", and "null" become real booleans and nulls, and numeric-looking values become real numbers, exactly as YAML specifies.
An honest note about scope, shown in the tool itself: this parser supports the common YAML subset. Anchors and aliases (&anchor / *alias), multi-document files separated by ---, and complex mapping keys are out of scope — those belong to full-spec parsers. For everyday configs, compose files, and pipeline definitions, the subset covers everything you will actually write, and the converter tells you plainly if your input steps outside it.
YAML is also the language of automation. GitHub Actions workflows, GitLab CI pipelines, Ansible playbooks, and Kubernetes manifests are all YAML files that decide how software gets built, tested, and deployed. Converting one to JSON lets you query it with tools like jq, validate it against a JSON schema, or feed it into a dashboard — things that are awkward to do with raw YAML text. A quick convert-validate cycle catches the indentation slip that would otherwise fail your pipeline at 2 a.m.
Errors are friendly, not cryptic. If your YAML has an indentation mistake or a structural problem, the tool reports an approximate line number so you can find and fix it in seconds — never a blank page, never a silent failure. The output side offers pretty-printed (indented) or minified JSON, one-click Copy, and a Download .json button. A "Try an example" button preloads a nested YAML document so you can see mappings, lists, and block scalars convert correctly before touching your real file.
Configs are the backbone of every deployed project — and every project needs a home. FistHost web hosting starting at just $0.99 per month includes a free domain, so the app behind that YAML config can go live today on fast, reliable servers.
No. The parser runs entirely in JavaScript in your browser. Your configuration text never leaves your device — safe even for configs containing internal hostnames or secrets (though you should still avoid pasting real secrets anywhere).
Honestly, no — and the tool says so up front. Anchors/aliases (& / *), multi-document streams, and complex keys are outside the supported common subset. The vast majority of everyday configs do not use them.
They are auto-typed per YAML rules: unquoted true/false become booleans, null (~, null, empty) becomes null, and numeric-looking values become numbers. Quote a value to force it to stay a string.
Literal (|) preserves line breaks exactly as written — ideal for scripts and preformatted text. Folded (>) joins lines into a single flowing string — ideal for long prose. Both are supported.
Almost always indentation: YAML forbids tabs and requires consistent spacing. The error message includes an approximate line number — check that line first.
This tool converts YAML → JSON only. For the reverse direction, format the JSON first and convert with a dedicated JSON-to-YAML utility.
Yes — full-line and trailing comments starting with # are parsed and ignored, exactly as YAML specifies. They do not appear in the JSON output.
Yes — those are exactly the kind of everyday YAML this tool targets. Manifests and workflows use mappings, lists, nested indentation, and block scalars, all fully supported. Just note the honest scope: if your file uses anchors and aliases for repeated blocks, those are outside the supported subset.
Yes. JSON is technically a subset of YAML, so pasting JSON into the YAML box converts cleanly — handy when you want to reformat or minify a JSON document using this tool’s output toggles. Flow-style collections like {a: 1} and [1, 2] are handled the same way.
There is no artificial cap. Large manifests and compose files convert comfortably; only multi-megabyte documents are limited by your device's memory.
More free FistHost tools for structured data: JSON Formatter to validate the output, Diff Checker to compare configs, Word Counter, URL Encoder Decoder, and Base64 Encoder Decoder.
Turning configs into a live deployment? FistHost web hosting starting at just $0.99 per month comes with a free domain and one-click installs — convert your YAML here, launch the project today.
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