Configuration lives in YAML because people edit it, but APIs, validators, and diff tools want JSON.
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YAML to JSON
Yaml
Free · API · MCPToolYour platform
Use YAML to JSON three ways
The free YAML to JSON on this page works in your browser. The same workflow is available via REST API for apps and via MCP for Cursor, Claude, and other agents — one API key, one plan, one quota. This tool is part of the developer-apis module under Developer Tools.
- Free in browserUse YAML to JSON here — no account required.
- REST APICall from your server with
X-Api-Key. - MCP for agentsConnect Cursor or Claude to ToolYour MCP with the same key.
- 1. Get an API keySign in and open Dashboard → API Keys (works for REST and MCP).
- 2. Call or connectUse the REST API from your server, or paste the MCP URL into your agent config.
- 3. Same qualityOutput matches the free web tool across all three surfaces.
What is YAML to JSON?
Configuration lives in YAML because people edit it, but APIs, validators, and diff tools want JSON. This YAML to JSON converter parses your document with the standard js-yaml parser — so anchors, aliases, block scalars, quoting styles, and the usual core schema types behave as they do in your CI runner — and returns indented JSON.
Because it is a real parser rather than a line-based approximation, the failure modes are useful. An inconsistent indent, a tab where spaces were required, or a duplicate key surfaces as a parse error naming the problem instead of producing a document that is subtly wrong. Custom application-specific tags are not resolved, and a single document is expected rather than a multi-document stream. Round-tripping back the other way is available in JSON to YAML, though comments cannot survive the trip since JSON has no way to carry them.
Browser use is free and needs no signup. The same job runs over REST at POST https://api.toolyour.com/api/v1/developer-apis/yaml-to-json and over MCP at https://api.toolyour.com/mcp — one API key, one shared monthly credit pool, 1 credit per successful call.
What are common questions about YAML to JSON?
Does it support anchors and aliases?
Yes. It uses a standard YAML parser, so anchors, aliases, merge keys, and block scalars resolve the way your CI tooling resolves them.
What happens with invalid YAML?
You get a parse error and no output, rather than a partially converted document that hides the indentation mistake.
Are comments preserved?
No, and they cannot be. JSON has no comment syntax, so anything after a hash is dropped during conversion.
What are the key features of YAML to JSON?
Standard YAML parsing
Anchors, aliases, and block scalars are handled by a real parser, not a regex.
Pretty-printed JSON output
Indented result that is immediately readable and diffable.
Errors that name the problem
Invalid documents fail with a parser message instead of silently losing fidelity.
How do you use YAML to JSON?
Paste the YAML document
A pipeline definition, a Helm values file, or an application config.
Convert
Valid documents return indented JSON; invalid ones return the parse error.
Use the JSON
Feed an API, a schema validator, or a JSON-only diff tool.
The YAML gotchas this surfaces
Converting to JSON makes YAML's quieter surprises visible, because JSON has no ambiguity to hide them in. **Unquoted values that are not strings** — a version written as 1.10 is a number and loses its trailing zero, and country code
no parses as boolean false in older schema modes. **Indentation drift** — a nested block indented inconsistently reparents itself under the wrong key, which looks fine in YAML and is unmistakable in JSON.
**Duplicate keys** — later values silently overwrite earlier ones in many YAML tools. Seeing the flattened JSON is often the fastest way to notice a config is not doing what the file appears to say.Config conversion round trip
The two directions serve different jobs. Convert YAML to JSON here when a machine needs the document: an API request body, a JSON Schema validator, or a tool that only reads JSON. Convert back with JSON to YAML when a human needs to edit it and you want comments and readability, accepting that comments are added fresh rather than restored.
After converting, JSON Validator confirms the result parses cleanly and JSON Formatter adjusts indentation to whatever your repository expects.
Which JSON / data codegen tools sit in this cluster?
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