YAML Validator & Converter
Validate YAML with real line-and-column error messages, and convert in both directions between YAML and JSON — the fastest way to see what a config actually says. Parsed locally in your browser with a real YAML 1.2 parser; nothing is uploaded.
New to this? Read the YAML Validator & Converter guide →
Validating YAML
Paste any YAML — a Kubernetes manifest, CI pipeline, docker-compose file — and it parses with a real YAML 1.2 parser (the same js-yaml library most Node tooling uses). Errors come back with the line and column, which is what you actually need when a manifest fails to apply: YAML errors are nearly always an indentation or quoting slip several lines above where the symptom appears.
Converting between YAML and JSON
YAML is a superset of JSON's data model, so conversion is lossless for the structures that matter: maps, lists, strings, numbers, booleans, null. Going YAML → JSON is the quickest way to see what a config actually says once anchors, multi-line strings and type coercion resolve — the famous country: NO → false surprise is instantly visible in the JSON. Going JSON → YAML produces clean, 2-space-indented output for pasting into configs. Everything runs locally; your configs (which often contain internal hostnames and secrets) are never uploaded. See the guide for the YAML gotchas worth knowing.
Frequently asked questions
Is every JSON document valid YAML?
Yes — YAML 1.2 is a superset of JSON, so valid JSON parses as YAML unchanged. The reverse is not true: YAML adds comments, anchors, multi-line blocks and unquoted strings that JSON has no way to express, though the underlying data always converts cleanly.
What is the Norway problem?
In YAML 1.1, unquoted NO parses as the boolean false — so a country list turns Norway into false. Relatives include version: 1.20 becoming the number 1.2 and mode: 0755 becoming 493. The cure is quoting any scalar you mean as a string; converting to JSON here shows you instantly what the parser decided.
Why does my YAML fail with an error many lines below the mistake?
Indentation errors only become structurally impossible later — the parser reports where it gave up, not where you slipped. Check sibling alignment and hunt for tab characters (always illegal in YAML indentation) above the reported line.
Are my configs uploaded?
No. Parsing and conversion run entirely in your browser using the js-yaml library — important, since real configs are full of internal hostnames and the occasional secret.