YAML to JSON Converter — Free Online YML to JSON & YAML Validator

YAML to JSON Converter — Free Online YML to JSON & YAML Validator. Free online YAML to JSON converter.

Convert YAML or YML to clean JSON instantly with anchors, merge keys and multi-document support, custom indentation, sorted keys and line-precise YAML validation — 100% in your browser.

Our free YAML to JSON converter turns any YAML or YML file into clean, valid JSON as you type.

Paste a Kubernetes manifest, a Helm values file, a Docker Compose file, a GitHub Actions workflow, an OpenAPI spec or an Ansible playbook and convert YAML to JSON instantly — no upload, no signup.

Anchors (&anchor), aliases (*alias) and merge keys (<<) are fully resolved, booleans, numbers and nulls keep their real JSON types, and multiple documents separated by --- become a single JSON array, so even complex YML to JSON conversions work without data loss.

The built-in YAML validator acts as a lightweight YAML parser and syntax checker: if your indentation or flow syntax is wrong, you get a clear message with the exact line and column instead of a silent empty result.

Choose 2, 3 or 4-space, tab or minified JSON output and optionally sort object keys alphabetically to get stable, diff-friendly JSON for code reviews and config snapshots. Need the reverse direction? Use our JSON to YAML Converter.

To browse or prettify a YAML file as a tree, open the YAML Viewer.

Everything runs locally in your browser, so API tokens, database passwords and infrastructure secrets in your configs never leave your device, and this YAML to JSON online tool keeps working offline once loaded.

Load the sample to see anchors and merge keys in action, copy the JSON with one click, download it as converted.json, or share a link that restores your YAML and options. More converters: YAML to TOML, TOML to JSON, JSON Viewer and JSON to TypeScript.

Frequently asked questions

How do I convert YAML to JSON?

Paste your YAML into YAML input or click Load sample. The JSON output updates as you type; click Copy JSON, or Download .json to save it as converted.json.

Does the converter support YAML anchors, aliases and merge keys?

Yes. Anchors and aliases are expanded and merge keys are applied, so the JSON contains the fully resolved values. Load sample shows an example with a shared defaults block.

What happens with several YAML documents in one file?

If the input contains several documents separated by ---, each one is converted and the result is a JSON array with one item per document. A note shows how many documents were converted.

How do I change the JSON indentation or sort keys?

Pick an Indentation of 2, 3 (the default) or 4 spaces, Tab, or Minified for one-line JSON. Turn on Sort keys alphabetically to order object keys at every level.

Why does it say Invalid YAML syntax?

The YAML could not be parsed. The message gives the reason with the line and column, often wrong indentation, a tab used for indentation or a missing space after a colon. Fix that line and the JSON appears again.

Is my YAML uploaded to a server?

No. YAML parsing and JSON conversion run entirely in your browser, so config files with secrets stay on your device.

How to use this online tool

YAML to JSON Converter — Free Online YML to JSON & YAML Validator is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

YAML to JSON Converter — Free Online YML to JSON & YAML Validator keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use YAML to JSON Converter — Free Online YML to JSON & YAML Validator for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.