Related Tools
How to Use
- 1Select the 'YAML to JSON' or 'JSON to YAML' tab for your conversion direction.
- 2Paste your YAML or JSON content in the input area.
- 3Click Convert to parse and format the output.
- 4Review any error messages if the input has syntax issues.
- 5Copy the result or download as a .json or .yaml file.
About YAML ↔ JSON Converter
The YAML ↔ JSON Converter handles bidirectional conversion between YAML and JSON with standards-compliant parsing using the js-yaml library — the most widely used YAML parser in the JavaScript ecosystem with over 30 million weekly npm downloads, relied upon by tools like ESLint, Prettier, and Kubernetes client libraries. It implements the YAML 1.2 specification, which formally defines YAML as a superset of JSON. Paste YAML to get formatted JSON, or paste JSON to get clean YAML — both directions in a single tool.
YAML (YAML Ain't Markup Language, a recursive acronym) and JSON (JavaScript Object Notation, standardized as ECMA-404 and RFC 8259) represent the same data structures — objects, arrays, strings, numbers, booleans, and null — but with fundamentally different syntax philosophies. YAML uses indentation-based formatting inspired by Python that is easier for humans to read and write, while JSON uses braces and brackets that are unambiguous for machines to parse. Converting between them is one of the most common tasks in modern software development, particularly in cloud-native environments where infrastructure configuration (YAML) must interact with APIs and tooling (JSON).
Parse errors are displayed with clear messages including line numbers and column positions, making it easy to locate and fix syntax issues in files that may contain hundreds of lines. Common YAML errors include inconsistent indentation (mixing tabs and spaces, which YAML strictly forbids), missing colons after keys, incorrect multi-line string formatting with block scalars, and unquoted special values like 'yes' or 'no' being interpreted as booleans. Common JSON errors include trailing commas after the last element (valid in JavaScript but not in JSON per the specification), missing double quotes on keys, and single quotes instead of the required double quotes. The detailed error messages help you identify and resolve these issues quickly without guessing.
DevOps engineers are the heaviest users of this tool. Kubernetes manifests, Helm chart values, Docker Compose files, GitHub Actions workflows, GitLab CI/CD pipelines, Ansible playbooks, and Terraform configurations are all written in YAML. Converting to JSON is necessary when using these configurations with REST APIs (which universally accept JSON), validation tools like JSON Schema validators, programmatic processing in scripts using jq or Python, or when debugging complex nested structures by removing YAML's indentation ambiguity and viewing the explicit brace-bracket hierarchy that JSON provides.
Backend developers use the converter when working with configuration files, API payloads, and data serialization across different systems. Many APIs accept and return JSON, while configuration files for the same services are written in YAML — for example, a Spring Boot application.yml that configures an API returning JSON responses. Being able to convert between formats without writing a script saves time and eliminates transcription errors that are especially dangerous in infrastructure configuration. The tool also serves as an effective YAML validator — if your YAML converts to JSON without errors, it is syntactically valid according to the YAML 1.2 specification.
All conversion runs entirely in your browser using the js-yaml library. No data is transmitted to any server, making it safe for converting configuration files that contain API keys, database credentials, service endpoints, secret tokens, and other sensitive infrastructure details that should never be pasted into cloud-based tools. Whether you are working with production Kubernetes secrets or staging environment variables, your data stays on your device throughout the entire conversion process.
Frequently Asked Questions
What YAML features are supported?
Full YAML 1.2 support via the js-yaml library, including nested objects, arrays, multi-line strings (literal block scalar | and folded block scalar >), anchors (&) and aliases (*), merge keys (<<), all scalar types (strings, integers, floats, booleans, null, dates), and flow-style inline syntax. This covers everything you would encounter in Kubernetes manifests, Docker Compose files, CI/CD pipelines, and application configuration.
Can I download the converted output?
Yes. Both JSON and YAML outputs can be downloaded as files (.json or .yaml/.yml) using the Download button. This is useful for converting configuration files and saving them directly without copy-paste, preserving the exact formatting produced by the converter.
Is JSON valid YAML?
Yes. YAML is a superset of JSON — every valid JSON document is also valid YAML by specification. You can paste JSON into the YAML input and it will parse successfully. This means YAML parsers can read JSON files natively, which is why some tools accept both formats interchangeably.
Does it show error line numbers?
Yes. When parsing fails, the error message includes the line number, column position, and a description of the syntax error. This makes it easy to locate the problem in your editor. Common issues include inconsistent indentation, missing colons, trailing commas in JSON, and incorrect multi-line string formatting in YAML.
Can I convert Kubernetes YAML to JSON?
Yes — this is one of the most common use cases. Paste any Kubernetes manifest, Helm values file, or Docker Compose configuration and convert it to JSON. This is useful for submitting configurations to the Kubernetes API (which accepts JSON), processing manifests programmatically, or debugging indentation issues by viewing the data in JSON's unambiguous brace/bracket syntax.
Why does my YAML parse differently than expected?
YAML has several common gotchas. Unquoted values like 'yes', 'no', 'on', 'off' are interpreted as booleans. Unquoted values like '1.0' may be interpreted as numbers. Tab characters cause parse errors because YAML only allows spaces for indentation. Colons in values without quotes can be misread as key-value separators. If your output looks wrong, check for these issues and use quotes around ambiguous values.
Can I use this tool as a YAML validator?
Yes. If your YAML converts to JSON without errors, it is syntactically valid YAML. The error messages with line numbers make this an effective debugging tool for catching indentation errors, missing colons, and other syntax issues in configuration files before deploying them.
What is the difference between .yaml and .yml file extensions?
There is no difference — both extensions are used for YAML files. The .yaml extension is the officially recommended extension per the YAML specification, but .yml is widely used due to historical convention (especially in Docker Compose, Travis CI, and other tools that adopted the shorter extension). Both are equally valid and interchangeable.