YAML Validator · Browser Tool

YAML Validator Online

Validate common YAML locally, find indentation and duplicate-key errors, format valid documents, and convert YAML to JSON without uploading the pasted content.

Validate YAMLHow it works

Local by default: parsing and conversion run in this browser tab. This is an independent tool, not an official Kubernetes, OpenAPI, or YAML project.

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Readable YAML checks

See where common document errors occur.

Local YAML workspace

Validate, format, and convert a YAML document.

Supported: common YAML 1.2 mappings, sequences, scalars, comments, anchors, aliases, and JSON-like flow collections. Advanced tags, block scalars, and full Kubernetes/OpenAPI semantics are outside this lightweight parser.

YAML input

Formatted YAML

Paste YAML or load the example to begin.

No YAML has been parsed yet.

JSON conversion

What gets checked

Syntax, indentation, duplicate keys, scalar values, anchors, aliases, and common JSON-like arrays/objects. Errors show line, column, and path when available.

JSON, YAML, and API testing

Prepare structured data for QA work.

Use the validator for readable YAML checks, then move into schema, API, and test-data workflows.

JSON Formatter

Format, minify, and inspect JSON locally.

JSON Schema Validator

Validate a JSON instance against a schema.

OpenAPI Validator

Inspect OpenAPI structure and references.

API Testing Tools

Move from document checks into API workflows.

Test Data Generator

Create fictional JSON, CSV, and SQL fixtures.

Test Plan Template

Document scope, environments, risks, and release criteria.

How to validate YAML

  1. Paste a YAML mapping or sequence, or load an example.
  2. Click Validate YAML to see syntax, indentation, duplicate-key, and reference errors.
  3. Use Format YAML for normalized common YAML output.
  4. Copy or download YAML, or use the JSON conversion in another QA tool.

YAML validator FAQ

Is this an online YAML validator?

It is available online, but the supplied YAML is parsed in the current browser tab. The page does not upload the document to a validation service.

Does it validate Kubernetes manifests?

It can check common YAML syntax in a manifest, but it does not perform Kubernetes schema, resource, or API-version validation. Use a Kubernetes-aware tool for semantic checks.

Why do I see an indentation error?

YAML nesting is represented by spaces. Keep sibling keys aligned, avoid tabs for indentation, and use a consistent two-space style.

Can it convert YAML to JSON?

Yes. After a successful parse, the local result appears as formatted JSON and can be copied or downloaded.